From 21eaa08017635a404d6ac777a2099c496e3aeb6a Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Mon, 22 Apr 2024 15:25:21 -0400
Subject: [PATCH] fix some tests

---
 packages/svelte/messages/compile-errors/css.md     |  4 ++--
 packages/svelte/messages/compile-errors/parse.md   |  2 +-
 packages/svelte/messages/compile-errors/runes.md   |  4 ++--
 packages/svelte/src/compiler/errors.js             |  8 ++++----
 .../svelte/src/compiler/phases/1-parse/index.js    |  2 +-
 .../src/compiler/phases/1-parse/state/element.js   |  4 ++--
 .../src/compiler/phases/2-analyze/validation.js    |  7 +++++--
 .../samples/attribute-empty/_config.js             |  2 +-
 .../attribute-sequence-expression-2/_config.js     |  2 +-
 .../attribute-sequence-expression/_config.js       |  2 +-
 .../samples/attribute-unique-binding/_config.js    |  2 +-
 .../samples/attribute-unique-shorthand/_config.js  |  2 +-
 .../samples/attribute-unique/_config.js            |  2 +-
 .../samples/catch-before-closing/_config.js        |  2 +-
 .../samples/catch-without-await/_config.js         |  2 +-
 .../samples/class-state-field-static/_config.js    |  5 +++--
 .../samples/comment-unclosed/_config.js            |  4 ++--
 .../component-slot-duplicate-error-2/_config.js    |  2 +-
 .../component-slot-duplicate-error-3/_config.js    |  2 +-
 .../component-slot-duplicate-error-4/_config.js    |  2 +-
 .../component-slot-duplicate-error-5/_config.js    |  2 +-
 .../component-slot-duplicate-error-6/_config.js    |  2 +-
 .../component-slot-duplicate-error/_config.js      |  2 +-
 .../component-slot-nested-error-2/_config.js       |  2 +-
 .../component-slot-nested-error-3/_config.js       |  2 +-
 .../samples/component-slot-nested-error/_config.js |  2 +-
 .../samples/css-global-block-combinator/_config.js |  2 +-
 .../css-global-block-declaration/_config.js        |  2 +-
 .../samples/css-global-block-modifier/_config.js   |  2 +-
 .../samples/css-global-block-multiple/_config.js   |  2 +-
 .../tests/compiler-errors/samples/css/_config.js   |  2 +-
 .../samples/dollar-binding-declaration/_config.js  |  2 +-
 .../samples/dollar-binding-global-js/_config.js    |  4 ++--
 .../samples/dollar-binding-global/_config.js       |  4 ++--
 .../samples/dollar-binding-import/_config.js       |  2 +-
 .../dynamic-element-binding-invalid/_config.js     |  4 ++--
 .../samples/else-before-closing-2/_config.js       |  2 +-
 .../samples/else-before-closing-3/_config.js       |  2 +-
 .../samples/else-before-closing/_config.js         |  2 +-
 .../samples/else-if-before-closing-2/_config.js    |  2 +-
 .../samples/else-if-before-closing/_config.js      |  2 +-
 .../samples/else-if-without-if/_config.js          |  2 +-
 .../samples/empty-attribute-shorthand/_config.js   |  2 +-
 .../samples/empty-classname-binding/_config.js     |  2 +-
 .../samples/empty-directive-name/_config.js        |  2 +-
 .../samples/export-derived-state/_config.js        |  2 +-
 .../samples/export-state-module/_config.js         |  2 +-
 .../samples/export-state/_config.js                |  2 +-
 .../samples/illegal-expression/_config.js          |  2 +-
 .../samples/invalid-snippet-binding/_config.js     |  2 +-
 .../samples/invalid-snippet-mutation/_config.js    |  2 +-
 .../samples/legacy-no-const-assignment/_config.js  |  4 ++--
 .../samples/legacy-no-const-update/_config.js      |  4 ++--
 .../samples/multiple-styles/_config.js             |  4 ++--
 .../samples/options-children/_config.js            |  2 +-
 .../samples/raw-mustaches-whitespace/_config.js    |  2 +-
 .../samples/render-tag-invalid-call/_config.js     |  2 +-
 .../samples/runes-before-after-update/_config.js   |  2 +-
 .../samples/runes-duplicate-props/_config.js       |  4 ++--
 .../samples/runes-export-let/_config.js            |  2 +-
 .../samples/runes-export-named-state/_config.js    |  2 +-
 .../samples/runes-invalid-each-binding/_config.js  |  4 ++--
 .../samples/runes-invalid-each-mutation/_config.js |  4 ++--
 .../samples/runes-no-const-assignment/_config.js   |  4 ++--
 .../samples/runes-no-const-update/_config.js       |  4 ++--
 .../samples/runes-no-derived-assignment/_config.js |  4 ++--
 .../samples/runes-no-derived-binding/_config.js    |  4 ++--
 .../_config.js                                     |  4 ++--
 .../runes-no-derived-state-field-update/_config.js |  4 ++--
 .../samples/runes-no-derived-update/_config.js     |  4 ++--
 .../samples/runes-no-rune-each/_config.js          |  4 ++--
 .../samples/runes-prop-export-conflict/_config.js  |  2 +-
 .../samples/runes-wrong-bindable-args/_config.js   |  4 ++--
 .../runes-wrong-bindable-placement/_config.js      |  4 ++--
 .../samples/runes-wrong-derived-args/_config.js    |  4 ++--
 .../runes-wrong-derived-placement/_config.js       |  5 +++--
 .../samples/runes-wrong-effect-args/_config.js     |  4 ++--
 .../runes-wrong-effect-placement/_config.js        |  4 ++--
 .../samples/runes-wrong-host-placement/_config.js  |  4 ++--
 .../samples/runes-wrong-props-args/_config.js      |  4 ++--
 .../samples/runes-wrong-props-placement/_config.js |  4 ++--
 .../samples/runes-wrong-state-args/_config.js      |  4 ++--
 .../samples/runes-wrong-state-placement/_config.js |  4 ++--
 .../runes-wrong-state-snapshot-args/_config.js     |  4 ++--
 .../samples/script-unclosed-eof/_config.js         |  2 +-
 .../samples/script-unclosed/_config.js             |  4 ++--
 .../samples/self-reference/_config.js              |  4 ++--
 .../slot-conflicting-with-render-tag/_config.js    |  4 ++--
 .../samples/snippet-children-conflict/_config.js   |  2 +-
 .../store-autosub-context-module/_config.js        |  4 ++--
 .../samples/store-contextual/_config.js            |  2 +-
 .../samples/store-global-disallowed/_config.js     |  4 ++--
 .../store-prevent-user-declarations/_config.js     |  2 +-
 .../samples/store-shadow-scope-2/_config.js        |  2 +-
 .../samples/store-shadow-scope-3/_config.js        |  2 +-
 .../samples/store-shadow-scope/_config.js          |  2 +-
 .../store-template-expression-scope/_config.js     |  2 +-
 .../samples/style-unclosed-eof/_config.js          |  2 +-
 .../samples/style-unclosed/_config.js              |  2 +-
 .../samples/svelte-selfdestructive/_config.js      |  4 ++--
 .../samples/then-before-closing/_config.js         |  2 +-
 .../samples/then-without-await/_config.js          |  2 +-
 .../unclosed-attribute-self-close-tag/_config.js   |  2 +-
 .../samples/unexpected-end-of-input-b/_config.js   |  2 +-
 .../samples/unexpected-end-of-input-c/_config.js   |  2 +-
 .../samples/unexpected-end-of-input/_config.js     |  2 +-
 .../unmatched-closing-tag-autoclose-2/_config.js   |  2 +-
 .../unmatched-closing-tag-autoclose/_config.js     |  2 +-
 .../samples/unmatched-closing-tag/_config.js       |  2 +-
 .../samples/void-closing/_config.js                |  2 +-
 .../samples/window-children/_config.js             |  2 +-
 .../samples/window-duplicate/_config.js            |  2 +-
 .../samples/window-inside-block/_config.js         |  2 +-
 .../samples/window-inside-element/_config.js       |  2 +-
 .../samples/action-on-component/errors.json        |  2 +-
 .../samples/animation-duplicate/errors.json        |  2 +-
 .../samples/animation-not-in-each/errors.json      |  2 +-
 .../animation-not-in-keyed-each/errors.json        |  2 +-
 .../samples/animation-on-component/errors.json     |  2 +-
 .../samples/animation-siblings/errors.json         |  2 +-
 .../samples/assignment-to-const-2/errors.json      |  4 ++--
 .../samples/assignment-to-const-3/errors.json      |  4 ++--
 .../samples/assignment-to-const-4/errors.json      |  4 ++--
 .../samples/assignment-to-const-5/errors.json      |  4 ++--
 .../samples/assignment-to-const-7/errors.json      |  4 ++--
 .../samples/assignment-to-const/errors.json        |  4 ++--
 .../samples/attribute-expected-equals/errors.json  |  2 +-
 .../samples/attribute-invalid-name-2/errors.json   |  2 +-
 .../samples/attribute-invalid-name-3/errors.json   |  2 +-
 .../samples/attribute-invalid-name-4/errors.json   |  2 +-
 .../samples/attribute-invalid-name-5/errors.json   |  2 +-
 .../samples/attribute-invalid-name/errors.json     |  2 +-
 .../samples/binding-await-catch/errors.json        | 12 +++++++++---
 .../samples/binding-await-then-2/errors.json       | 12 +++++++++---
 .../samples/binding-await-then/errors.json         | 12 +++++++++---
 .../validator/samples/binding-const/errors.json    |  2 +-
 .../samples/binding-dimensions-svg/errors.json     |  4 ++--
 .../samples/binding-input-checked/errors.json      |  4 ++--
 .../samples/binding-input-type-boolean/errors.json |  2 +-
 .../binding-invalid-foreign-namespace/errors.json  |  2 +-
 .../binding-invalid-on-element-2/errors.json       |  4 ++--
 .../samples/binding-invalid-on-element/errors.json |  4 ++--
 .../binding-invalid-value-global/errors.json       |  2 +-
 .../samples/binding-invalid-value/errors.json      |  2 +-
 .../validator/samples/binding-invalid/errors.json  |  2 +-
 .../validator/samples/binding-let/errors.json      |  2 +-
 .../binding-select-multiple-dynamic/errors.json    |  2 +-
 .../component-event-modifiers-invalid/errors.json  |  2 +-
 .../component-invalid-style-directive/errors.json  | 12 +++++++++---
 .../component-slot-default-reserved/errors.json    |  2 +-
 .../component-slot-dynamic-attribute/errors.json   |  2 +-
 .../samples/component-slot-dynamic/errors.json     |  2 +-
 .../component-slotted-custom-element-2/errors.json | 12 +++++++++---
 .../component-slotted-each-block/errors.json       |  2 +-
 .../samples/component-slotted-if-block/errors.json |  2 +-
 .../samples/const-tag-conflict-1/errors.json       | 12 +++++++++---
 .../samples/const-tag-conflict-2/errors.json       | 12 +++++++++---
 .../samples/const-tag-placement-1/errors.json      | 12 +++++++++---
 .../samples/const-tag-placement-2/errors.json      | 12 +++++++++---
 .../samples/const-tag-readonly-1/errors.json       | 14 ++++++++++----
 .../samples/const-tag-readonly-2/errors.json       | 12 +++++++++---
 .../samples/contenteditable-dynamic/errors.json    |  2 +-
 .../samples/contenteditable-missing/errors.json    |  2 +-
 .../css-invalid-combinator-selector-1/errors.json  |  2 +-
 .../css-invalid-combinator-selector-2/errors.json  |  2 +-
 .../css-invalid-combinator-selector-3/errors.json  |  2 +-
 .../css-invalid-combinator-selector-4/errors.json  |  2 +-
 .../css-invalid-global-placement-2/errors.json     |  2 +-
 .../css-invalid-global-placement-3/errors.json     |  2 +-
 .../css-invalid-global-placement-4/errors.json     |  2 +-
 .../css-invalid-global-placement-5/errors.json     |  2 +-
 .../css-invalid-global-placement-6/errors.json     |  2 +-
 .../css-invalid-global-placement/errors.json       |  2 +-
 .../css-invalid-global-selector-2/errors.json      |  2 +-
 .../css-invalid-global-selector-3/errors.json      |  2 +-
 .../css-invalid-global-selector-4/errors.json      |  2 +-
 .../css-invalid-global-selector-5/errors.json      |  2 +-
 .../css-invalid-global-selector-6/errors.json      |  2 +-
 .../css-invalid-global-selector-list/errors.json   |  2 +-
 .../css-invalid-global-selector/errors.json        |  2 +-
 .../errors.json                                    |  2 +-
 .../samples/css-mismatched-quotes/errors.json      |  2 +-
 .../samples/debug-invalid-args/errors.json         |  2 +-
 .../default-export-anonymous-class/errors.json     |  2 +-
 .../default-export-anonymous-function/errors.json  |  2 +-
 .../validator/samples/default-export/errors.json   |  2 +-
 .../samples/directive-non-expression/errors.json   |  2 +-
 .../dollar-dollar-global-in-markup/errors.json     |  2 +-
 .../dollar-dollar-global-in-script/errors.json     |  2 +-
 .../samples/dollar-global-in-markup/errors.json    |  2 +-
 .../samples/dollar-global-in-script/errors.json    |  2 +-
 .../dynamic-element-invalid-tag/errors.json        |  2 +-
 .../dynamic-element-missing-tag/errors.json        |  2 +-
 .../samples/dynamic-element-this/errors.json       |  2 +-
 .../errors.json                                    |  2 +-
 .../errors.json                                    |  2 +-
 .../errors.json                                    |  2 +-
 .../samples/each-block-invalid-context/errors.json |  2 +-
 .../validator/samples/event-attribute/errors.json  |  2 +-
 .../event-modifiers-invalid-nonpassive/errors.json |  2 +-
 .../event-modifiers-invalid-passive/errors.json    |  2 +-
 .../samples/event-modifiers-invalid/errors.json    |  2 +-
 .../samples/html-block-in-attribute/errors.json    | 12 +++++++++---
 .../samples/html-block-in-textarea/errors.json     | 12 +++++++++---
 .../illegal-variable-declaration/errors.json       |  2 +-
 .../invalid-empty-css-declaration/errors.json      |  2 +-
 .../samples/invalid-node-placement-2/errors.json   |  2 +-
 .../samples/invalid-node-placement/errors.json     |  2 +-
 .../validator/samples/let-directive/errors.json    | 12 +++++++++---
 .../samples/logic-block-in-attribute/errors.json   | 12 +++++++++---
 .../samples/logic-block-in-textarea/errors.json    | 12 +++++++++---
 .../multiple-script-default-context/errors.json    |  2 +-
 .../multiple-script-module-context/errors.json     |  2 +-
 .../samples/namespace-invalid/errors.json          |  2 +-
 .../samples/namespace-non-literal/errors.json      |  2 +-
 .../reactive-declaration-cyclical/errors.json      | 12 +++++++++---
 .../samples/script-invalid-context/errors.json     |  2 +-
 .../samples/slot-attribute-invalid/errors.json     |  2 +-
 .../style-directive-modifiers-invalid/errors.json  |  2 +-
 .../svelte-fragment-placement-2/errors.json        | 12 +++++++++---
 .../samples/svelte-fragment-placement/errors.json  | 12 +++++++++---
 .../samples/svelte-head-attributes/errors.json     | 12 +++++++++---
 .../validator/samples/tag-invalid/errors.json      |  2 +-
 .../validator/samples/tag-non-string/errors.json   |  2 +-
 .../samples/textarea-value-children/errors.json    |  2 +-
 .../samples/title-no-attributes/errors.json        |  2 +-
 .../samples/title-no-children/errors.json          |  2 +-
 .../transition-duplicate-in-transition/errors.json |  2 +-
 .../samples/transition-duplicate-in/errors.json    |  2 +-
 .../errors.json                                    |  2 +-
 .../samples/transition-duplicate-out/errors.json   |  2 +-
 .../transition-duplicate-transition-in/errors.json |  2 +-
 .../errors.json                                    |  2 +-
 .../transition-duplicate-transition/errors.json    |  2 +-
 .../samples/transition-on-component/errors.json    |  2 +-
 .../window-binding-invalid-innerwidth/errors.json  |  2 +-
 .../samples/window-binding-invalid/errors.json     |  2 +-
 237 files changed, 457 insertions(+), 332 deletions(-)

diff --git a/packages/svelte/messages/compile-errors/css.md b/packages/svelte/messages/compile-errors/css.md
index 440f7f7b28..02acd29e5a 100644
--- a/packages/svelte/messages/compile-errors/css.md
+++ b/packages/svelte/messages/compile-errors/css.md
@@ -44,7 +44,7 @@ Invalid selector
 
 ## invalid_css_identifier
 
-TODO
+Expected a valid CSS identifier
 
 ## invalid_nesting_selector
 
@@ -52,4 +52,4 @@ Nesting selectors can only be used inside a rule
 
 ## invalid_css_declaration
 
-TODO
\ No newline at end of file
+TODO
diff --git a/packages/svelte/messages/compile-errors/parse.md b/packages/svelte/messages/compile-errors/parse.md
index da250c92cd..e09c61e419 100644
--- a/packages/svelte/messages/compile-errors/parse.md
+++ b/packages/svelte/messages/compile-errors/parse.md
@@ -1,6 +1,6 @@
 ## unclosed_element
 
-%name% was left open
+`<%name%>` was left open
 
 ## unclosed_block
 
diff --git a/packages/svelte/messages/compile-errors/runes.md b/packages/svelte/messages/compile-errors/runes.md
index 33d9280cc2..c8efa4eefb 100644
--- a/packages/svelte/messages/compile-errors/runes.md
+++ b/packages/svelte/messages/compile-errors/runes.md
@@ -56,11 +56,11 @@ Cannot export derived state from a module. To expose the current derived value,
 
 ## invalid_assignment
 
-Cannot assign to `%thing%`
+Cannot assign to %thing%
 
 ## invalid_binding
 
-Cannot bind to `%thing%`
+Cannot bind to %thing%
 
 ## invalid_rune_args
 
diff --git a/packages/svelte/src/compiler/errors.js b/packages/svelte/src/compiler/errors.js
index 870c2581c2..0dfee4ec16 100644
--- a/packages/svelte/src/compiler/errors.js
+++ b/packages/svelte/src/compiler/errors.js
@@ -418,7 +418,7 @@ export function invalid_css_selector(node) {
  * @returns {never}
  */
 export function invalid_css_identifier(node) {
-	e(node, "invalid_css_identifier", "TODO");
+	e(node, "invalid_css_identifier", "Expected a valid CSS identifier");
 }
 
 /**
@@ -518,7 +518,7 @@ export function cyclical_reactive_declaration(node, cycle) {
  * @returns {never}
  */
 export function unclosed_element(node, name) {
-	e(node, "unclosed_element", `${name} was left open`);
+	e(node, "unclosed_element", `\`<${name}>\` was left open`);
 }
 
 /**
@@ -981,7 +981,7 @@ export function invalid_host_location(node) {
  * @returns {never}
  */
 export function invalid_assignment(node, thing) {
-	e(node, "invalid_assignment", `Cannot assign to \`${thing}\``);
+	e(node, "invalid_assignment", `Cannot assign to ${thing}`);
 }
 
 /**
@@ -990,7 +990,7 @@ export function invalid_assignment(node, thing) {
  * @returns {never}
  */
 export function invalid_binding(node, thing) {
-	e(node, "invalid_binding", `Cannot bind to \`${thing}\``);
+	e(node, "invalid_binding", `Cannot bind to ${thing}`);
 }
 
 /**
diff --git a/packages/svelte/src/compiler/phases/1-parse/index.js b/packages/svelte/src/compiler/phases/1-parse/index.js
index 0982f4a960..d5f5cda052 100644
--- a/packages/svelte/src/compiler/phases/1-parse/index.js
+++ b/packages/svelte/src/compiler/phases/1-parse/index.js
@@ -92,7 +92,7 @@ export class Parser {
 
 			if (current.type === 'RegularElement') {
 				current.end = current.start + 1;
-				e.unclosed_element(current, `<${current.name}>`);
+				e.unclosed_element(current, current.name);
 			} else {
 				current.end = current.start + 1;
 				e.unclosed_block(current);
diff --git a/packages/svelte/src/compiler/phases/1-parse/state/element.js b/packages/svelte/src/compiler/phases/1-parse/state/element.js
index 811cf6a218..78988af6d1 100644
--- a/packages/svelte/src/compiler/phases/1-parse/state/element.js
+++ b/packages/svelte/src/compiler/phases/1-parse/state/element.js
@@ -677,7 +677,7 @@ function read_attribute_value(parser) {
 			'in attribute value'
 		);
 	} catch (/** @type {any} */ error) {
-		if (error.code === 'js-parse-error') {
+		if (error.code === 'js_parse_error') {
 			// if the attribute value didn't close + self-closing tag
 			// eg: `<Component test={{a:1} />`
 			// acorn may throw a `Unterminated regular expression` because of `/>`
@@ -687,7 +687,7 @@ function read_attribute_value(parser) {
 				e.unclosed_attribute_value(pos, quote_mark || '}');
 			}
 		}
-		throw e;
+		throw error;
 	}
 
 	if (value.length === 0 && !quote_mark) {
diff --git a/packages/svelte/src/compiler/phases/2-analyze/validation.js b/packages/svelte/src/compiler/phases/2-analyze/validation.js
index 8d7e6348c5..7a416a2af0 100644
--- a/packages/svelte/src/compiler/phases/2-analyze/validation.js
+++ b/packages/svelte/src/compiler/phases/2-analyze/validation.js
@@ -1023,10 +1023,13 @@ function validate_no_const_assignment(node, argument, scope, is_binding) {
 			// 		(binding.kind !== 'normal' || !binding.initial)
 			// );
 
+			// TODO have a more specific error message for assignments to things like `{:then foo}`
+			const thing = 'constant';
+
 			if (is_binding) {
-				e.invalid_binding(node, 'TODO');
+				e.invalid_binding(node, thing);
 			} else {
-				e.invalid_assignment(node, 'TODO');
+				e.invalid_assignment(node, thing);
 			}
 		}
 	}
diff --git a/packages/svelte/tests/compiler-errors/samples/attribute-empty/_config.js b/packages/svelte/tests/compiler-errors/samples/attribute-empty/_config.js
index 248fc1107e..9c29f505ee 100644
--- a/packages/svelte/tests/compiler-errors/samples/attribute-empty/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/attribute-empty/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'missing-attribute-value',
+		code: 'missing_attribute_value',
 		message: 'Expected attribute value',
 		position: [12, 12]
 	}
diff --git a/packages/svelte/tests/compiler-errors/samples/attribute-sequence-expression-2/_config.js b/packages/svelte/tests/compiler-errors/samples/attribute-sequence-expression-2/_config.js
index 5fc3e7b5fa..e655d40aae 100644
--- a/packages/svelte/tests/compiler-errors/samples/attribute-sequence-expression-2/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/attribute-sequence-expression-2/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'invalid-sequence-expression',
+		code: 'invalid_sequence_expression',
 		message:
 			'Sequence expressions are not allowed as attribute/directive values in runes mode, unless wrapped in parentheses',
 		position: [124, 131]
diff --git a/packages/svelte/tests/compiler-errors/samples/attribute-sequence-expression/_config.js b/packages/svelte/tests/compiler-errors/samples/attribute-sequence-expression/_config.js
index 79ddec267b..15549974d3 100644
--- a/packages/svelte/tests/compiler-errors/samples/attribute-sequence-expression/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/attribute-sequence-expression/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'invalid-sequence-expression',
+		code: 'invalid_sequence_expression',
 		message:
 			'Sequence expressions are not allowed as attribute/directive values in runes mode, unless wrapped in parentheses',
 		position: [163, 170]
diff --git a/packages/svelte/tests/compiler-errors/samples/attribute-unique-binding/_config.js b/packages/svelte/tests/compiler-errors/samples/attribute-unique-binding/_config.js
index e933cebbf5..5fb31858b7 100644
--- a/packages/svelte/tests/compiler-errors/samples/attribute-unique-binding/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/attribute-unique-binding/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'duplicate-attribute',
+		code: 'duplicate_attribute',
 		message: 'Attributes need to be unique',
 		position: [17, 17]
 	}
diff --git a/packages/svelte/tests/compiler-errors/samples/attribute-unique-shorthand/_config.js b/packages/svelte/tests/compiler-errors/samples/attribute-unique-shorthand/_config.js
index e933cebbf5..5fb31858b7 100644
--- a/packages/svelte/tests/compiler-errors/samples/attribute-unique-shorthand/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/attribute-unique-shorthand/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'duplicate-attribute',
+		code: 'duplicate_attribute',
 		message: 'Attributes need to be unique',
 		position: [17, 17]
 	}
diff --git a/packages/svelte/tests/compiler-errors/samples/attribute-unique/_config.js b/packages/svelte/tests/compiler-errors/samples/attribute-unique/_config.js
index e933cebbf5..5fb31858b7 100644
--- a/packages/svelte/tests/compiler-errors/samples/attribute-unique/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/attribute-unique/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'duplicate-attribute',
+		code: 'duplicate_attribute',
 		message: 'Attributes need to be unique',
 		position: [17, 17]
 	}
diff --git a/packages/svelte/tests/compiler-errors/samples/catch-before-closing/_config.js b/packages/svelte/tests/compiler-errors/samples/catch-before-closing/_config.js
index 1a50076da4..52786af6d8 100644
--- a/packages/svelte/tests/compiler-errors/samples/catch-before-closing/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/catch-before-closing/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'expected-token',
+		code: 'expected_token',
 		message: 'Expected token {:else}',
 		position: [35, 35]
 	}
diff --git a/packages/svelte/tests/compiler-errors/samples/catch-without-await/_config.js b/packages/svelte/tests/compiler-errors/samples/catch-without-await/_config.js
index 64c85f85c9..b24874f1b4 100644
--- a/packages/svelte/tests/compiler-errors/samples/catch-without-await/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/catch-without-await/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'invalid-continuing-block-placement',
+		code: 'invalid_continuing_block_placement',
 		message:
 			'{:...} block is invalid at this position (did you forget to close the preceeding element or block?)',
 		position: [1, 1]
diff --git a/packages/svelte/tests/compiler-errors/samples/class-state-field-static/_config.js b/packages/svelte/tests/compiler-errors/samples/class-state-field-static/_config.js
index dca19b4606..d212e197f0 100644
--- a/packages/svelte/tests/compiler-errors/samples/class-state-field-static/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/class-state-field-static/_config.js
@@ -2,8 +2,9 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'invalid-state-location',
-		message: '$state(...) can only be used as a variable declaration initializer or a class field',
+		code: 'invalid_state_location',
+		message:
+			'`$state(...)` can only be used as a variable declaration initializer or a class field',
 		position: [33, 41]
 	}
 });
diff --git a/packages/svelte/tests/compiler-errors/samples/comment-unclosed/_config.js b/packages/svelte/tests/compiler-errors/samples/comment-unclosed/_config.js
index 7c00375ad6..38bc06f415 100644
--- a/packages/svelte/tests/compiler-errors/samples/comment-unclosed/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/comment-unclosed/_config.js
@@ -2,8 +2,8 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'unexpected-eof',
-		message: 'Unexpected end of input (expected -->)',
+		code: 'expected_token',
+		message: 'Expected token -->',
 		position: [24, 24]
 	}
 });
diff --git a/packages/svelte/tests/compiler-errors/samples/component-slot-duplicate-error-2/_config.js b/packages/svelte/tests/compiler-errors/samples/component-slot-duplicate-error-2/_config.js
index 0085693908..2dafcd66b1 100644
--- a/packages/svelte/tests/compiler-errors/samples/component-slot-duplicate-error-2/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/component-slot-duplicate-error-2/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'duplicate-slot-name',
+		code: 'duplicate_slot_name',
 		message: "Duplicate slot name 'foo' in <Nested>"
 	}
 });
diff --git a/packages/svelte/tests/compiler-errors/samples/component-slot-duplicate-error-3/_config.js b/packages/svelte/tests/compiler-errors/samples/component-slot-duplicate-error-3/_config.js
index 0085693908..2dafcd66b1 100644
--- a/packages/svelte/tests/compiler-errors/samples/component-slot-duplicate-error-3/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/component-slot-duplicate-error-3/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'duplicate-slot-name',
+		code: 'duplicate_slot_name',
 		message: "Duplicate slot name 'foo' in <Nested>"
 	}
 });
diff --git a/packages/svelte/tests/compiler-errors/samples/component-slot-duplicate-error-4/_config.js b/packages/svelte/tests/compiler-errors/samples/component-slot-duplicate-error-4/_config.js
index 78e10808bd..1a8d68c564 100644
--- a/packages/svelte/tests/compiler-errors/samples/component-slot-duplicate-error-4/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/component-slot-duplicate-error-4/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'invalid-default-slot-content',
+		code: 'invalid_default_slot_content',
 		message: 'Found default slot content alongside an explicit slot="default"'
 	}
 });
diff --git a/packages/svelte/tests/compiler-errors/samples/component-slot-duplicate-error-5/_config.js b/packages/svelte/tests/compiler-errors/samples/component-slot-duplicate-error-5/_config.js
index 0085693908..2dafcd66b1 100644
--- a/packages/svelte/tests/compiler-errors/samples/component-slot-duplicate-error-5/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/component-slot-duplicate-error-5/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'duplicate-slot-name',
+		code: 'duplicate_slot_name',
 		message: "Duplicate slot name 'foo' in <Nested>"
 	}
 });
diff --git a/packages/svelte/tests/compiler-errors/samples/component-slot-duplicate-error-6/_config.js b/packages/svelte/tests/compiler-errors/samples/component-slot-duplicate-error-6/_config.js
index 0085693908..2dafcd66b1 100644
--- a/packages/svelte/tests/compiler-errors/samples/component-slot-duplicate-error-6/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/component-slot-duplicate-error-6/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'duplicate-slot-name',
+		code: 'duplicate_slot_name',
 		message: "Duplicate slot name 'foo' in <Nested>"
 	}
 });
diff --git a/packages/svelte/tests/compiler-errors/samples/component-slot-duplicate-error/_config.js b/packages/svelte/tests/compiler-errors/samples/component-slot-duplicate-error/_config.js
index 0085693908..2dafcd66b1 100644
--- a/packages/svelte/tests/compiler-errors/samples/component-slot-duplicate-error/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/component-slot-duplicate-error/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'duplicate-slot-name',
+		code: 'duplicate_slot_name',
 		message: "Duplicate slot name 'foo' in <Nested>"
 	}
 });
diff --git a/packages/svelte/tests/compiler-errors/samples/component-slot-nested-error-2/_config.js b/packages/svelte/tests/compiler-errors/samples/component-slot-nested-error-2/_config.js
index 69c2adb23c..727e0c8bda 100644
--- a/packages/svelte/tests/compiler-errors/samples/component-slot-nested-error-2/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/component-slot-nested-error-2/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'invalid-slot-placement',
+		code: 'invalid_slot_placement',
 		message:
 			"Element with a slot='...' attribute must be a child of a component or a descendant of a custom element"
 	}
diff --git a/packages/svelte/tests/compiler-errors/samples/component-slot-nested-error-3/_config.js b/packages/svelte/tests/compiler-errors/samples/component-slot-nested-error-3/_config.js
index 69c2adb23c..727e0c8bda 100644
--- a/packages/svelte/tests/compiler-errors/samples/component-slot-nested-error-3/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/component-slot-nested-error-3/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'invalid-slot-placement',
+		code: 'invalid_slot_placement',
 		message:
 			"Element with a slot='...' attribute must be a child of a component or a descendant of a custom element"
 	}
diff --git a/packages/svelte/tests/compiler-errors/samples/component-slot-nested-error/_config.js b/packages/svelte/tests/compiler-errors/samples/component-slot-nested-error/_config.js
index 69c2adb23c..727e0c8bda 100644
--- a/packages/svelte/tests/compiler-errors/samples/component-slot-nested-error/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/component-slot-nested-error/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'invalid-slot-placement',
+		code: 'invalid_slot_placement',
 		message:
 			"Element with a slot='...' attribute must be a child of a component or a descendant of a custom element"
 	}
diff --git a/packages/svelte/tests/compiler-errors/samples/css-global-block-combinator/_config.js b/packages/svelte/tests/compiler-errors/samples/css-global-block-combinator/_config.js
index 6a11aa63ec..77baf5a87e 100644
--- a/packages/svelte/tests/compiler-errors/samples/css-global-block-combinator/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/css-global-block-combinator/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'invalid-css-global-block-combinator',
+		code: 'invalid_css_global_block_combinator',
 		message: 'A :global {...} block cannot follow a > combinator',
 		position: [12, 21]
 	}
diff --git a/packages/svelte/tests/compiler-errors/samples/css-global-block-declaration/_config.js b/packages/svelte/tests/compiler-errors/samples/css-global-block-declaration/_config.js
index 7b637ca42e..5d2a52465f 100644
--- a/packages/svelte/tests/compiler-errors/samples/css-global-block-declaration/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/css-global-block-declaration/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'invalid-css-global-block-declaration',
+		code: 'invalid_css_global_block_declaration',
 		message: 'A :global {...} block can only contain rules, not declarations',
 		position: [24, 34]
 	}
diff --git a/packages/svelte/tests/compiler-errors/samples/css-global-block-modifier/_config.js b/packages/svelte/tests/compiler-errors/samples/css-global-block-modifier/_config.js
index 9e7cac667f..63b20e7e36 100644
--- a/packages/svelte/tests/compiler-errors/samples/css-global-block-modifier/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/css-global-block-modifier/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'invalid-css-global-block-modifier',
+		code: 'invalid_css_global_block_modifier',
 		message: 'A :global {...} block cannot modify an existing selector',
 		position: [14, 21]
 	}
diff --git a/packages/svelte/tests/compiler-errors/samples/css-global-block-multiple/_config.js b/packages/svelte/tests/compiler-errors/samples/css-global-block-multiple/_config.js
index 8021a9c677..bb189b05f5 100644
--- a/packages/svelte/tests/compiler-errors/samples/css-global-block-multiple/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/css-global-block-multiple/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'invalid-css-global-block-list',
+		code: 'invalid_css_global_block_list',
 		message: 'A :global {...} block cannot be part of a selector list with more than one item',
 		position: [9, 31]
 	}
diff --git a/packages/svelte/tests/compiler-errors/samples/css/_config.js b/packages/svelte/tests/compiler-errors/samples/css/_config.js
index 9705cde6b5..74ef4c9c6c 100644
--- a/packages/svelte/tests/compiler-errors/samples/css/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/css/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'invalid-css-identifier',
+		code: 'invalid_css_identifier',
 		message: 'Expected a valid CSS identifier',
 		position: [25, 25]
 	}
diff --git a/packages/svelte/tests/compiler-errors/samples/dollar-binding-declaration/_config.js b/packages/svelte/tests/compiler-errors/samples/dollar-binding-declaration/_config.js
index a49d35d090..7141ff1efd 100644
--- a/packages/svelte/tests/compiler-errors/samples/dollar-binding-declaration/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/dollar-binding-declaration/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'invalid-dollar-binding',
+		code: 'invalid_dollar_binding',
 		message: 'The $ name is reserved, and cannot be used for variables and imports'
 	}
 });
diff --git a/packages/svelte/tests/compiler-errors/samples/dollar-binding-global-js/_config.js b/packages/svelte/tests/compiler-errors/samples/dollar-binding-global-js/_config.js
index 666b798323..ae86ca8d6b 100644
--- a/packages/svelte/tests/compiler-errors/samples/dollar-binding-global-js/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/dollar-binding-global-js/_config.js
@@ -2,8 +2,8 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'illegal-global',
+		code: 'illegal_global',
 		message:
-			'$ is an illegal variable name. To reference a global variable called $, use globalThis.$'
+			'`$` is an illegal variable name. To reference a global variable called `$`, use `globalThis.$`'
 	}
 });
diff --git a/packages/svelte/tests/compiler-errors/samples/dollar-binding-global/_config.js b/packages/svelte/tests/compiler-errors/samples/dollar-binding-global/_config.js
index 666b798323..ae86ca8d6b 100644
--- a/packages/svelte/tests/compiler-errors/samples/dollar-binding-global/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/dollar-binding-global/_config.js
@@ -2,8 +2,8 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'illegal-global',
+		code: 'illegal_global',
 		message:
-			'$ is an illegal variable name. To reference a global variable called $, use globalThis.$'
+			'`$` is an illegal variable name. To reference a global variable called `$`, use `globalThis.$`'
 	}
 });
diff --git a/packages/svelte/tests/compiler-errors/samples/dollar-binding-import/_config.js b/packages/svelte/tests/compiler-errors/samples/dollar-binding-import/_config.js
index a49d35d090..7141ff1efd 100644
--- a/packages/svelte/tests/compiler-errors/samples/dollar-binding-import/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/dollar-binding-import/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'invalid-dollar-binding',
+		code: 'invalid_dollar_binding',
 		message: 'The $ name is reserved, and cannot be used for variables and imports'
 	}
 });
diff --git a/packages/svelte/tests/compiler-errors/samples/dynamic-element-binding-invalid/_config.js b/packages/svelte/tests/compiler-errors/samples/dynamic-element-binding-invalid/_config.js
index 6934ea4c55..4bb3edc27b 100644
--- a/packages/svelte/tests/compiler-errors/samples/dynamic-element-binding-invalid/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/dynamic-element-binding-invalid/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'invalid-binding',
-		message: "'value' binding can only be used with <input>, <textarea>, <select>"
+		code: 'bind_invalid_target',
+		message: '`bind:value` can only be used with <input>, <textarea>, <select>'
 	}
 });
diff --git a/packages/svelte/tests/compiler-errors/samples/else-before-closing-2/_config.js b/packages/svelte/tests/compiler-errors/samples/else-before-closing-2/_config.js
index dc9aff145c..54ef1afa7b 100644
--- a/packages/svelte/tests/compiler-errors/samples/else-before-closing-2/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/else-before-closing-2/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'expected-token',
+		code: 'expected_token',
 		message: 'Expected token {:then ...} or {:catch ...}',
 		position: [24, 24]
 	}
diff --git a/packages/svelte/tests/compiler-errors/samples/else-before-closing-3/_config.js b/packages/svelte/tests/compiler-errors/samples/else-before-closing-3/_config.js
index 80a2a136db..c052f05a18 100644
--- a/packages/svelte/tests/compiler-errors/samples/else-before-closing-3/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/else-before-closing-3/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'invalid-continuing-block-placement',
+		code: 'invalid_continuing_block_placement',
 		message:
 			'{:...} block is invalid at this position (did you forget to close the preceeding element or block?)',
 		position: [6, 6]
diff --git a/packages/svelte/tests/compiler-errors/samples/else-before-closing/_config.js b/packages/svelte/tests/compiler-errors/samples/else-before-closing/_config.js
index 87c1296f49..6883152c09 100644
--- a/packages/svelte/tests/compiler-errors/samples/else-before-closing/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/else-before-closing/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'invalid-continuing-block-placement',
+		code: 'invalid_continuing_block_placement',
 		message:
 			'{:...} block is invalid at this position (did you forget to close the preceeding element or block?)',
 		position: [18, 18]
diff --git a/packages/svelte/tests/compiler-errors/samples/else-if-before-closing-2/_config.js b/packages/svelte/tests/compiler-errors/samples/else-if-before-closing-2/_config.js
index 4b4059cf3b..d2ab9b9090 100644
--- a/packages/svelte/tests/compiler-errors/samples/else-if-before-closing-2/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/else-if-before-closing-2/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'invalid-continuing-block-placement',
+		code: 'invalid_continuing_block_placement',
 		message:
 			'{:...} block is invalid at this position (did you forget to close the preceeding element or block?)',
 		position: [17, 17]
diff --git a/packages/svelte/tests/compiler-errors/samples/else-if-before-closing/_config.js b/packages/svelte/tests/compiler-errors/samples/else-if-before-closing/_config.js
index ae20d2da8c..da19e5e806 100644
--- a/packages/svelte/tests/compiler-errors/samples/else-if-before-closing/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/else-if-before-closing/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'expected-token',
+		code: 'expected_token',
 		message: 'Expected token {:then ...} or {:catch ...}',
 		position: [26, 26]
 	}
diff --git a/packages/svelte/tests/compiler-errors/samples/else-if-without-if/_config.js b/packages/svelte/tests/compiler-errors/samples/else-if-without-if/_config.js
index 04d8342f20..706e610cba 100644
--- a/packages/svelte/tests/compiler-errors/samples/else-if-without-if/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/else-if-without-if/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'expected-token',
+		code: 'expected_token',
 		message: 'Expected token {:then ...} or {:catch ...}',
 		position: [27, 27]
 	}
diff --git a/packages/svelte/tests/compiler-errors/samples/empty-attribute-shorthand/_config.js b/packages/svelte/tests/compiler-errors/samples/empty-attribute-shorthand/_config.js
index 5c6855f41b..fd20583e57 100644
--- a/packages/svelte/tests/compiler-errors/samples/empty-attribute-shorthand/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/empty-attribute-shorthand/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'empty-attribute-shorthand',
+		code: 'empty_attribute_shorthand',
 		message: 'Attribute shorthand cannot be empty',
 		position: [6, 6]
 	}
diff --git a/packages/svelte/tests/compiler-errors/samples/empty-classname-binding/_config.js b/packages/svelte/tests/compiler-errors/samples/empty-classname-binding/_config.js
index bd1d1d7682..087c2e55d9 100644
--- a/packages/svelte/tests/compiler-errors/samples/empty-classname-binding/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/empty-classname-binding/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'empty-directive-name',
+		code: 'empty_directive_name',
 		message: 'ClassDirective name cannot be empty',
 		position: [10, 10]
 	}
diff --git a/packages/svelte/tests/compiler-errors/samples/empty-directive-name/_config.js b/packages/svelte/tests/compiler-errors/samples/empty-directive-name/_config.js
index 48a0eb32c4..22338ec818 100644
--- a/packages/svelte/tests/compiler-errors/samples/empty-directive-name/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/empty-directive-name/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'empty-directive-name',
+		code: 'empty_directive_name',
 		message: 'UseDirective name cannot be empty',
 		position: [8, 8]
 	}
diff --git a/packages/svelte/tests/compiler-errors/samples/export-derived-state/_config.js b/packages/svelte/tests/compiler-errors/samples/export-derived-state/_config.js
index fd70495836..9e77a92f52 100644
--- a/packages/svelte/tests/compiler-errors/samples/export-derived-state/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/export-derived-state/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'invalid-derived-export',
+		code: 'invalid_derived_export',
 		message:
 			'Cannot export derived state from a module. To expose the current derived value, export a function returning its value',
 		position: [24, 66]
diff --git a/packages/svelte/tests/compiler-errors/samples/export-state-module/_config.js b/packages/svelte/tests/compiler-errors/samples/export-state-module/_config.js
index f1bad80670..3cc26ce501 100644
--- a/packages/svelte/tests/compiler-errors/samples/export-state-module/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/export-state-module/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'invalid-state-export',
+		code: 'invalid_state_export',
 		message:
 			"Cannot export state from a module if it is reassigned. Either export a function returning the state value or only mutate the state value's properties",
 		position: [76, 114]
diff --git a/packages/svelte/tests/compiler-errors/samples/export-state/_config.js b/packages/svelte/tests/compiler-errors/samples/export-state/_config.js
index 1f7bd0f767..94d31700f2 100644
--- a/packages/svelte/tests/compiler-errors/samples/export-state/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/export-state/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'invalid-state-export',
+		code: 'invalid_state_export',
 		message:
 			"Cannot export state from a module if it is reassigned. Either export a function returning the state value or only mutate the state value's properties",
 		position: [46, 86]
diff --git a/packages/svelte/tests/compiler-errors/samples/illegal-expression/_config.js b/packages/svelte/tests/compiler-errors/samples/illegal-expression/_config.js
index 887f11e882..bef5afd00d 100644
--- a/packages/svelte/tests/compiler-errors/samples/illegal-expression/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/illegal-expression/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'js-parse-error',
+		code: 'js_parse_error',
 		message: 'Assigning to rvalue',
 		position: [1, 1]
 	}
diff --git a/packages/svelte/tests/compiler-errors/samples/invalid-snippet-binding/_config.js b/packages/svelte/tests/compiler-errors/samples/invalid-snippet-binding/_config.js
index a507812928..b0ee9ddfd4 100644
--- a/packages/svelte/tests/compiler-errors/samples/invalid-snippet-binding/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/invalid-snippet-binding/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'invalid-snippet-assignment',
+		code: 'invalid_snippet_assignment',
 		message: 'Cannot reassign or bind to snippet parameter'
 	}
 });
diff --git a/packages/svelte/tests/compiler-errors/samples/invalid-snippet-mutation/_config.js b/packages/svelte/tests/compiler-errors/samples/invalid-snippet-mutation/_config.js
index a507812928..b0ee9ddfd4 100644
--- a/packages/svelte/tests/compiler-errors/samples/invalid-snippet-mutation/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/invalid-snippet-mutation/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'invalid-snippet-assignment',
+		code: 'invalid_snippet_assignment',
 		message: 'Cannot reassign or bind to snippet parameter'
 	}
 });
diff --git a/packages/svelte/tests/compiler-errors/samples/legacy-no-const-assignment/_config.js b/packages/svelte/tests/compiler-errors/samples/legacy-no-const-assignment/_config.js
index f2503be0e3..247cc5b09f 100644
--- a/packages/svelte/tests/compiler-errors/samples/legacy-no-const-assignment/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/legacy-no-const-assignment/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'invalid-const-assignment',
-		message: 'Invalid assignment to const variable'
+		code: 'invalid_assignment',
+		message: 'Cannot assign to constant'
 	}
 });
diff --git a/packages/svelte/tests/compiler-errors/samples/legacy-no-const-update/_config.js b/packages/svelte/tests/compiler-errors/samples/legacy-no-const-update/_config.js
index f2503be0e3..247cc5b09f 100644
--- a/packages/svelte/tests/compiler-errors/samples/legacy-no-const-update/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/legacy-no-const-update/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'invalid-const-assignment',
-		message: 'Invalid assignment to const variable'
+		code: 'invalid_assignment',
+		message: 'Cannot assign to constant'
 	}
 });
diff --git a/packages/svelte/tests/compiler-errors/samples/multiple-styles/_config.js b/packages/svelte/tests/compiler-errors/samples/multiple-styles/_config.js
index 50cf2583af..f42fd1af86 100644
--- a/packages/svelte/tests/compiler-errors/samples/multiple-styles/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/multiple-styles/_config.js
@@ -2,8 +2,8 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'duplicate-style-element',
-		message: 'A component can have a single top-level <style> element',
+		code: 'duplicate_style_element',
+		message: 'A component can have a single top-level `<style>` element',
 		position: [58, 58]
 	}
 });
diff --git a/packages/svelte/tests/compiler-errors/samples/options-children/_config.js b/packages/svelte/tests/compiler-errors/samples/options-children/_config.js
index d08406c499..5ec5f02752 100644
--- a/packages/svelte/tests/compiler-errors/samples/options-children/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/options-children/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'invalid-element-content',
+		code: 'invalid_element_content',
 		message: '<svelte:options> cannot have children',
 		position: [16, 16]
 	}
diff --git a/packages/svelte/tests/compiler-errors/samples/raw-mustaches-whitespace/_config.js b/packages/svelte/tests/compiler-errors/samples/raw-mustaches-whitespace/_config.js
index 67d197780e..06adb4706c 100644
--- a/packages/svelte/tests/compiler-errors/samples/raw-mustaches-whitespace/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/raw-mustaches-whitespace/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'missing-whitespace',
+		code: 'missing_whitespace',
 		message: 'Expected whitespace',
 		position: [6, 6]
 	}
diff --git a/packages/svelte/tests/compiler-errors/samples/render-tag-invalid-call/_config.js b/packages/svelte/tests/compiler-errors/samples/render-tag-invalid-call/_config.js
index 47bd37699c..f1380710e2 100644
--- a/packages/svelte/tests/compiler-errors/samples/render-tag-invalid-call/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/render-tag-invalid-call/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'invalid-render-call',
+		code: 'invalid_render_call',
 		message: 'Calling a snippet function using apply, bind or call is not allowed'
 	}
 });
diff --git a/packages/svelte/tests/compiler-errors/samples/runes-before-after-update/_config.js b/packages/svelte/tests/compiler-errors/samples/runes-before-after-update/_config.js
index d597478bb2..7b2f863d7c 100644
--- a/packages/svelte/tests/compiler-errors/samples/runes-before-after-update/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/runes-before-after-update/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'invalid-runes-mode-import',
+		code: 'invalid_runes_mode_import',
 		message: 'beforeUpdate cannot be used in runes mode'
 	}
 });
diff --git a/packages/svelte/tests/compiler-errors/samples/runes-duplicate-props/_config.js b/packages/svelte/tests/compiler-errors/samples/runes-duplicate-props/_config.js
index d2a4eab786..9620704d61 100644
--- a/packages/svelte/tests/compiler-errors/samples/runes-duplicate-props/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/runes-duplicate-props/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'duplicate-props-rune',
-		message: 'Cannot use $props() more than once'
+		code: 'duplicate_props_rune',
+		message: 'Cannot use `$props()` more than once'
 	}
 });
diff --git a/packages/svelte/tests/compiler-errors/samples/runes-export-let/_config.js b/packages/svelte/tests/compiler-errors/samples/runes-export-let/_config.js
index 800bdbe853..50cfed6032 100644
--- a/packages/svelte/tests/compiler-errors/samples/runes-export-let/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/runes-export-let/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'invalid-legacy-export',
+		code: 'invalid_legacy_export',
 		message: 'Cannot use `export let` in runes mode — use $props instead'
 	}
 });
diff --git a/packages/svelte/tests/compiler-errors/samples/runes-export-named-state/_config.js b/packages/svelte/tests/compiler-errors/samples/runes-export-named-state/_config.js
index fb1be5730b..22f2f6596a 100644
--- a/packages/svelte/tests/compiler-errors/samples/runes-export-named-state/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/runes-export-named-state/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'invalid-state-export',
+		code: 'invalid_state_export',
 		message:
 			"Cannot export state from a module if it is reassigned. Either export a function returning the state value or only mutate the state value's properties",
 		position: [28, 53]
diff --git a/packages/svelte/tests/compiler-errors/samples/runes-invalid-each-binding/_config.js b/packages/svelte/tests/compiler-errors/samples/runes-invalid-each-binding/_config.js
index 55eb0280ae..e60f4e86e7 100644
--- a/packages/svelte/tests/compiler-errors/samples/runes-invalid-each-binding/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/runes-invalid-each-binding/_config.js
@@ -2,8 +2,8 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'invalid-each-assignment',
+		code: 'invalid_each_assignment',
 		message:
-			"Cannot reassign or bind to each block argument in runes mode. Use the array and index variables instead (e.g. 'array[i] = value' instead of 'entry = value')"
+			'Cannot reassign or bind to each block argument in runes mode. Use the array and index variables instead (e.g. `array[i] = value` instead of `entry = value`)'
 	}
 });
diff --git a/packages/svelte/tests/compiler-errors/samples/runes-invalid-each-mutation/_config.js b/packages/svelte/tests/compiler-errors/samples/runes-invalid-each-mutation/_config.js
index 55eb0280ae..e60f4e86e7 100644
--- a/packages/svelte/tests/compiler-errors/samples/runes-invalid-each-mutation/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/runes-invalid-each-mutation/_config.js
@@ -2,8 +2,8 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'invalid-each-assignment',
+		code: 'invalid_each_assignment',
 		message:
-			"Cannot reassign or bind to each block argument in runes mode. Use the array and index variables instead (e.g. 'array[i] = value' instead of 'entry = value')"
+			'Cannot reassign or bind to each block argument in runes mode. Use the array and index variables instead (e.g. `array[i] = value` instead of `entry = value`)'
 	}
 });
diff --git a/packages/svelte/tests/compiler-errors/samples/runes-no-const-assignment/_config.js b/packages/svelte/tests/compiler-errors/samples/runes-no-const-assignment/_config.js
index f2503be0e3..247cc5b09f 100644
--- a/packages/svelte/tests/compiler-errors/samples/runes-no-const-assignment/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/runes-no-const-assignment/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'invalid-const-assignment',
-		message: 'Invalid assignment to const variable'
+		code: 'invalid_assignment',
+		message: 'Cannot assign to constant'
 	}
 });
diff --git a/packages/svelte/tests/compiler-errors/samples/runes-no-const-update/_config.js b/packages/svelte/tests/compiler-errors/samples/runes-no-const-update/_config.js
index f2503be0e3..247cc5b09f 100644
--- a/packages/svelte/tests/compiler-errors/samples/runes-no-const-update/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/runes-no-const-update/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'invalid-const-assignment',
-		message: 'Invalid assignment to const variable'
+		code: 'invalid_assignment',
+		message: 'Cannot assign to constant'
 	}
 });
diff --git a/packages/svelte/tests/compiler-errors/samples/runes-no-derived-assignment/_config.js b/packages/svelte/tests/compiler-errors/samples/runes-no-derived-assignment/_config.js
index 6e40da1a81..1fae570f91 100644
--- a/packages/svelte/tests/compiler-errors/samples/runes-no-derived-assignment/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/runes-no-derived-assignment/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'invalid-derived-assignment',
-		message: 'Invalid assignment to derived state'
+		code: 'invalid_assignment',
+		message: 'Cannot assign to derived state'
 	}
 });
diff --git a/packages/svelte/tests/compiler-errors/samples/runes-no-derived-binding/_config.js b/packages/svelte/tests/compiler-errors/samples/runes-no-derived-binding/_config.js
index 3a27b1f9bd..b2f418e384 100644
--- a/packages/svelte/tests/compiler-errors/samples/runes-no-derived-binding/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/runes-no-derived-binding/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'invalid-derived-binding',
-		message: 'Invalid binding to derived state'
+		code: 'invalid_binding',
+		message: 'Cannot bind to derived state'
 	}
 });
diff --git a/packages/svelte/tests/compiler-errors/samples/runes-no-derived-state-field-assignment/_config.js b/packages/svelte/tests/compiler-errors/samples/runes-no-derived-state-field-assignment/_config.js
index 6e40da1a81..1fae570f91 100644
--- a/packages/svelte/tests/compiler-errors/samples/runes-no-derived-state-field-assignment/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/runes-no-derived-state-field-assignment/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'invalid-derived-assignment',
-		message: 'Invalid assignment to derived state'
+		code: 'invalid_assignment',
+		message: 'Cannot assign to derived state'
 	}
 });
diff --git a/packages/svelte/tests/compiler-errors/samples/runes-no-derived-state-field-update/_config.js b/packages/svelte/tests/compiler-errors/samples/runes-no-derived-state-field-update/_config.js
index 6e40da1a81..1fae570f91 100644
--- a/packages/svelte/tests/compiler-errors/samples/runes-no-derived-state-field-update/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/runes-no-derived-state-field-update/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'invalid-derived-assignment',
-		message: 'Invalid assignment to derived state'
+		code: 'invalid_assignment',
+		message: 'Cannot assign to derived state'
 	}
 });
diff --git a/packages/svelte/tests/compiler-errors/samples/runes-no-derived-update/_config.js b/packages/svelte/tests/compiler-errors/samples/runes-no-derived-update/_config.js
index 6e40da1a81..1fae570f91 100644
--- a/packages/svelte/tests/compiler-errors/samples/runes-no-derived-update/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/runes-no-derived-update/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'invalid-derived-assignment',
-		message: 'Invalid assignment to derived state'
+		code: 'invalid_assignment',
+		message: 'Cannot assign to derived state'
 	}
 });
diff --git a/packages/svelte/tests/compiler-errors/samples/runes-no-rune-each/_config.js b/packages/svelte/tests/compiler-errors/samples/runes-no-rune-each/_config.js
index 9089b6acca..00edfe51b3 100644
--- a/packages/svelte/tests/compiler-errors/samples/runes-no-rune-each/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/runes-no-rune-each/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'invalid-state-location',
-		message: '$state(...) can only be used as a variable declaration initializer or a class field'
+		code: 'invalid_state_location',
+		message: '`$state(...)` can only be used as a variable declaration initializer or a class field'
 	}
 });
diff --git a/packages/svelte/tests/compiler-errors/samples/runes-prop-export-conflict/_config.js b/packages/svelte/tests/compiler-errors/samples/runes-prop-export-conflict/_config.js
index a6e4a4c018..cfd4f2cb67 100644
--- a/packages/svelte/tests/compiler-errors/samples/runes-prop-export-conflict/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/runes-prop-export-conflict/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'conflicting-property-name',
+		code: 'conflicting_property_name',
 		message: 'Cannot have a property and a component export with the same name'
 	}
 });
diff --git a/packages/svelte/tests/compiler-errors/samples/runes-wrong-bindable-args/_config.js b/packages/svelte/tests/compiler-errors/samples/runes-wrong-bindable-args/_config.js
index 0d1d0e0709..1024076a6a 100644
--- a/packages/svelte/tests/compiler-errors/samples/runes-wrong-bindable-args/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/runes-wrong-bindable-args/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'invalid-rune-args-length',
-		message: '$bindable can only be called with 0 or 1 arguments'
+		code: 'invalid_rune_args_length',
+		message: '`$bindable` must be called with zero or one arguments'
 	}
 });
diff --git a/packages/svelte/tests/compiler-errors/samples/runes-wrong-bindable-placement/_config.js b/packages/svelte/tests/compiler-errors/samples/runes-wrong-bindable-placement/_config.js
index bc92ee9ced..76d48b43be 100644
--- a/packages/svelte/tests/compiler-errors/samples/runes-wrong-bindable-placement/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/runes-wrong-bindable-placement/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'invalid-bindable-location',
-		message: '$bindable() can only be used inside a $props() declaration'
+		code: 'invalid_bindable_location',
+		message: '`$bindable()` can only be used inside a `$props()` declaration'
 	}
 });
diff --git a/packages/svelte/tests/compiler-errors/samples/runes-wrong-derived-args/_config.js b/packages/svelte/tests/compiler-errors/samples/runes-wrong-derived-args/_config.js
index 7a37736485..4b9ad2c572 100644
--- a/packages/svelte/tests/compiler-errors/samples/runes-wrong-derived-args/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/runes-wrong-derived-args/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'invalid-rune-args-length',
-		message: '$derived can only be called with 1 argument'
+		code: 'invalid_rune_args_length',
+		message: '`$derived` must be called with exactly one argument'
 	}
 });
diff --git a/packages/svelte/tests/compiler-errors/samples/runes-wrong-derived-placement/_config.js b/packages/svelte/tests/compiler-errors/samples/runes-wrong-derived-placement/_config.js
index 73c8bf1299..5bde7150ec 100644
--- a/packages/svelte/tests/compiler-errors/samples/runes-wrong-derived-placement/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/runes-wrong-derived-placement/_config.js
@@ -2,7 +2,8 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'invalid-state-location',
-		message: '$derived(...) can only be used as a variable declaration initializer or a class field'
+		code: 'invalid_state_location',
+		message:
+			'`$derived(...)` can only be used as a variable declaration initializer or a class field'
 	}
 });
diff --git a/packages/svelte/tests/compiler-errors/samples/runes-wrong-effect-args/_config.js b/packages/svelte/tests/compiler-errors/samples/runes-wrong-effect-args/_config.js
index 3ebcd022a9..ed08b7682a 100644
--- a/packages/svelte/tests/compiler-errors/samples/runes-wrong-effect-args/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/runes-wrong-effect-args/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'invalid-rune-args-length',
-		message: '$effect can only be called with 1 argument'
+		code: 'invalid_rune_args_length',
+		message: '`$effect` must be called with exactly one argument'
 	}
 });
diff --git a/packages/svelte/tests/compiler-errors/samples/runes-wrong-effect-placement/_config.js b/packages/svelte/tests/compiler-errors/samples/runes-wrong-effect-placement/_config.js
index 529fe44137..b8c4ad0c05 100644
--- a/packages/svelte/tests/compiler-errors/samples/runes-wrong-effect-placement/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/runes-wrong-effect-placement/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'invalid-effect-location',
-		message: '$effect() can only be used as an expression statement'
+		code: 'invalid_effect_location',
+		message: '`$effect()` can only be used as an expression statement'
 	}
 });
diff --git a/packages/svelte/tests/compiler-errors/samples/runes-wrong-host-placement/_config.js b/packages/svelte/tests/compiler-errors/samples/runes-wrong-host-placement/_config.js
index f848528c6c..37c34a7384 100644
--- a/packages/svelte/tests/compiler-errors/samples/runes-wrong-host-placement/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/runes-wrong-host-placement/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'invalid-host-location',
-		message: '$host() can only be used inside custom element component instances'
+		code: 'invalid_host_location',
+		message: '`$host()` can only be used inside custom element component instances'
 	}
 });
diff --git a/packages/svelte/tests/compiler-errors/samples/runes-wrong-props-args/_config.js b/packages/svelte/tests/compiler-errors/samples/runes-wrong-props-args/_config.js
index c37b3486bd..eb6bc22ed5 100644
--- a/packages/svelte/tests/compiler-errors/samples/runes-wrong-props-args/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/runes-wrong-props-args/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'invalid-rune-args-length',
-		message: '$props can only be called with 0 arguments'
+		code: 'invalid_rune_args',
+		message: '`$props` cannot be called with arguments'
 	}
 });
diff --git a/packages/svelte/tests/compiler-errors/samples/runes-wrong-props-placement/_config.js b/packages/svelte/tests/compiler-errors/samples/runes-wrong-props-placement/_config.js
index 0067f4f986..ebf5040fff 100644
--- a/packages/svelte/tests/compiler-errors/samples/runes-wrong-props-placement/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/runes-wrong-props-placement/_config.js
@@ -2,8 +2,8 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'invalid-props-location',
+		code: 'invalid_props_location',
 		message:
-			'$props() can only be used at the top level of components as a variable declaration initializer'
+			'`$props()` can only be used at the top level of components as a variable declaration initializer'
 	}
 });
diff --git a/packages/svelte/tests/compiler-errors/samples/runes-wrong-state-args/_config.js b/packages/svelte/tests/compiler-errors/samples/runes-wrong-state-args/_config.js
index 2d995aa0c1..30fd430140 100644
--- a/packages/svelte/tests/compiler-errors/samples/runes-wrong-state-args/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/runes-wrong-state-args/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'invalid-rune-args-length',
-		message: '$state can only be called with 0 or 1 arguments'
+		code: 'invalid_rune_args_length',
+		message: '`$state` must be called with zero or one arguments'
 	}
 });
diff --git a/packages/svelte/tests/compiler-errors/samples/runes-wrong-state-placement/_config.js b/packages/svelte/tests/compiler-errors/samples/runes-wrong-state-placement/_config.js
index 9089b6acca..00edfe51b3 100644
--- a/packages/svelte/tests/compiler-errors/samples/runes-wrong-state-placement/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/runes-wrong-state-placement/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'invalid-state-location',
-		message: '$state(...) can only be used as a variable declaration initializer or a class field'
+		code: 'invalid_state_location',
+		message: '`$state(...)` can only be used as a variable declaration initializer or a class field'
 	}
 });
diff --git a/packages/svelte/tests/compiler-errors/samples/runes-wrong-state-snapshot-args/_config.js b/packages/svelte/tests/compiler-errors/samples/runes-wrong-state-snapshot-args/_config.js
index c701cfac7e..ab7ce7b201 100644
--- a/packages/svelte/tests/compiler-errors/samples/runes-wrong-state-snapshot-args/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/runes-wrong-state-snapshot-args/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'invalid-rune-args-length',
-		message: '$state.snapshot can only be called with 1 argument'
+		code: 'invalid_rune_args_length',
+		message: '`$state.snapshot` must be called with exactly one argument'
 	}
 });
diff --git a/packages/svelte/tests/compiler-errors/samples/script-unclosed-eof/_config.js b/packages/svelte/tests/compiler-errors/samples/script-unclosed-eof/_config.js
index c8b496e41e..5c2c74eb54 100644
--- a/packages/svelte/tests/compiler-errors/samples/script-unclosed-eof/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/script-unclosed-eof/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'unexpected-eof',
+		code: 'unexpected_eof',
 		message: 'Unexpected end of input',
 		position: [32, 32]
 	}
diff --git a/packages/svelte/tests/compiler-errors/samples/script-unclosed/_config.js b/packages/svelte/tests/compiler-errors/samples/script-unclosed/_config.js
index 30c59d6f28..04ec9db510 100644
--- a/packages/svelte/tests/compiler-errors/samples/script-unclosed/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/script-unclosed/_config.js
@@ -2,8 +2,8 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'unclosed-element',
-		message: '<script> was left open',
+		code: 'unclosed_element',
+		message: '`<script>` was left open',
 		position: [32, 32]
 	}
 });
diff --git a/packages/svelte/tests/compiler-errors/samples/self-reference/_config.js b/packages/svelte/tests/compiler-errors/samples/self-reference/_config.js
index 8148e18332..be27484ce6 100644
--- a/packages/svelte/tests/compiler-errors/samples/self-reference/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/self-reference/_config.js
@@ -2,9 +2,9 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'invalid-self-placement',
+		code: 'invalid_self_placement',
 		message:
-			'<svelte:self> components can only exist inside {#if} blocks, {#each} blocks, {#snippet} blocks or slots passed to components',
+			'`<svelte:self>` components can only exist inside {#if} blocks, {#each} blocks, {#snippet} blocks or slots passed to components',
 		position: [1, 1]
 	}
 });
diff --git a/packages/svelte/tests/compiler-errors/samples/slot-conflicting-with-render-tag/_config.js b/packages/svelte/tests/compiler-errors/samples/slot-conflicting-with-render-tag/_config.js
index c027d4fd5b..d85305d319 100644
--- a/packages/svelte/tests/compiler-errors/samples/slot-conflicting-with-render-tag/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/slot-conflicting-with-render-tag/_config.js
@@ -2,9 +2,9 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'conflicting-slot-usage',
+		code: 'conflicting_slot_usage',
 		message:
-			'Cannot use <slot> syntax and {@render ...} tags in the same component. Migrate towards {@render ...} tags completely.',
+			'Cannot use `<slot>` syntax and `{@render ...}` tags in the same component. Migrate towards `{@render ...}` tags completely.',
 		position: [71, 84]
 	}
 });
diff --git a/packages/svelte/tests/compiler-errors/samples/snippet-children-conflict/_config.js b/packages/svelte/tests/compiler-errors/samples/snippet-children-conflict/_config.js
index 3fd2caaeda..747c75ad3a 100644
--- a/packages/svelte/tests/compiler-errors/samples/snippet-children-conflict/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/snippet-children-conflict/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'conflicting-children-snippet',
+		code: 'conflicting_children_snippet',
 		message:
 			'Cannot use explicit children snippet at the same time as implicit children content. Remove either the non-whitespace content or the children snippet block',
 		position: [320, 353]
diff --git a/packages/svelte/tests/compiler-errors/samples/store-autosub-context-module/_config.js b/packages/svelte/tests/compiler-errors/samples/store-autosub-context-module/_config.js
index 526d292530..5f45a792bf 100644
--- a/packages/svelte/tests/compiler-errors/samples/store-autosub-context-module/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/store-autosub-context-module/_config.js
@@ -2,8 +2,8 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'illegal-subscription',
-		message: 'Cannot reference store value inside <script context="module">',
+		code: 'illegal_subscription',
+		message: 'Cannot reference store value inside `<script context="module">`',
 		position: [164, 168]
 	}
 });
diff --git a/packages/svelte/tests/compiler-errors/samples/store-contextual/_config.js b/packages/svelte/tests/compiler-errors/samples/store-contextual/_config.js
index 2a7d0fa0ec..6a49672737 100644
--- a/packages/svelte/tests/compiler-errors/samples/store-contextual/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/store-contextual/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'illegal-store-subscription',
+		code: 'illegal_store_subscription',
 		message: 'Cannot subscribe to stores that are not declared at the top level of the component'
 	}
 });
diff --git a/packages/svelte/tests/compiler-errors/samples/store-global-disallowed/_config.js b/packages/svelte/tests/compiler-errors/samples/store-global-disallowed/_config.js
index 94a461f3aa..649aeffd37 100644
--- a/packages/svelte/tests/compiler-errors/samples/store-global-disallowed/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/store-global-disallowed/_config.js
@@ -2,8 +2,8 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'illegal-global',
+		code: 'illegal_global',
 		message:
-			'$foo is an illegal variable name. To reference a global variable called $foo, use globalThis.$foo'
+			'`$foo` is an illegal variable name. To reference a global variable called `$foo`, use `globalThis.$foo`'
 	}
 });
diff --git a/packages/svelte/tests/compiler-errors/samples/store-prevent-user-declarations/_config.js b/packages/svelte/tests/compiler-errors/samples/store-prevent-user-declarations/_config.js
index 97bc9d4c3d..d2ef4fa288 100644
--- a/packages/svelte/tests/compiler-errors/samples/store-prevent-user-declarations/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/store-prevent-user-declarations/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'invalid-dollar-prefix',
+		code: 'invalid_dollar_prefix',
 		message: 'The $ prefix is reserved, and cannot be used for variables and imports'
 	}
 });
diff --git a/packages/svelte/tests/compiler-errors/samples/store-shadow-scope-2/_config.js b/packages/svelte/tests/compiler-errors/samples/store-shadow-scope-2/_config.js
index f320abac21..85112aa728 100644
--- a/packages/svelte/tests/compiler-errors/samples/store-shadow-scope-2/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/store-shadow-scope-2/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'illegal-store-subscription',
+		code: 'illegal_store_subscription',
 		message: 'Cannot subscribe to stores that are not declared at the top level of the component',
 		position: [142, 147]
 	}
diff --git a/packages/svelte/tests/compiler-errors/samples/store-shadow-scope-3/_config.js b/packages/svelte/tests/compiler-errors/samples/store-shadow-scope-3/_config.js
index 74e25f3bf1..dea59242b9 100644
--- a/packages/svelte/tests/compiler-errors/samples/store-shadow-scope-3/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/store-shadow-scope-3/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'illegal-store-subscription',
+		code: 'illegal_store_subscription',
 		message: 'Cannot subscribe to stores that are not declared at the top level of the component',
 		position: [167, 172]
 	}
diff --git a/packages/svelte/tests/compiler-errors/samples/store-shadow-scope/_config.js b/packages/svelte/tests/compiler-errors/samples/store-shadow-scope/_config.js
index 2a7d0fa0ec..6a49672737 100644
--- a/packages/svelte/tests/compiler-errors/samples/store-shadow-scope/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/store-shadow-scope/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'illegal-store-subscription',
+		code: 'illegal_store_subscription',
 		message: 'Cannot subscribe to stores that are not declared at the top level of the component'
 	}
 });
diff --git a/packages/svelte/tests/compiler-errors/samples/store-template-expression-scope/_config.js b/packages/svelte/tests/compiler-errors/samples/store-template-expression-scope/_config.js
index 2a7d0fa0ec..6a49672737 100644
--- a/packages/svelte/tests/compiler-errors/samples/store-template-expression-scope/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/store-template-expression-scope/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'illegal-store-subscription',
+		code: 'illegal_store_subscription',
 		message: 'Cannot subscribe to stores that are not declared at the top level of the component'
 	}
 });
diff --git a/packages/svelte/tests/compiler-errors/samples/style-unclosed-eof/_config.js b/packages/svelte/tests/compiler-errors/samples/style-unclosed-eof/_config.js
index 8d27a7297d..e915428ca6 100644
--- a/packages/svelte/tests/compiler-errors/samples/style-unclosed-eof/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/style-unclosed-eof/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'expected-token',
+		code: 'expected_token',
 		message: 'Expected token </style',
 		position: [31, 31]
 	}
diff --git a/packages/svelte/tests/compiler-errors/samples/style-unclosed/_config.js b/packages/svelte/tests/compiler-errors/samples/style-unclosed/_config.js
index 602f196039..294867d7f5 100644
--- a/packages/svelte/tests/compiler-errors/samples/style-unclosed/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/style-unclosed/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'invalid-css-identifier',
+		code: 'invalid_css_identifier',
 		message: 'Expected a valid CSS identifier',
 		position: [9, 9]
 	}
diff --git a/packages/svelte/tests/compiler-errors/samples/svelte-selfdestructive/_config.js b/packages/svelte/tests/compiler-errors/samples/svelte-selfdestructive/_config.js
index b88609ffe9..f5ff354027 100644
--- a/packages/svelte/tests/compiler-errors/samples/svelte-selfdestructive/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/svelte-selfdestructive/_config.js
@@ -2,9 +2,9 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'invalid-svelte-tag',
+		code: 'invalid_svelte_tag',
 		message:
-			'Valid <svelte:...> tag names are svelte:head, svelte:options, svelte:window, svelte:document, svelte:body, svelte:element, svelte:component, svelte:self or svelte:fragment',
+			'Valid `<svelte:...>` tag names are svelte:head, svelte:options, svelte:window, svelte:document, svelte:body, svelte:element, svelte:component, svelte:self or svelte:fragment',
 		position: [10, 10]
 	}
 });
diff --git a/packages/svelte/tests/compiler-errors/samples/then-before-closing/_config.js b/packages/svelte/tests/compiler-errors/samples/then-before-closing/_config.js
index 7c1ea02cc1..cef6538067 100644
--- a/packages/svelte/tests/compiler-errors/samples/then-before-closing/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/then-before-closing/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'invalid-continuing-block-placement',
+		code: 'invalid_continuing_block_placement',
 		message:
 			'{:...} block is invalid at this position (did you forget to close the preceeding element or block?)',
 		position: [21, 21]
diff --git a/packages/svelte/tests/compiler-errors/samples/then-without-await/_config.js b/packages/svelte/tests/compiler-errors/samples/then-without-await/_config.js
index 64c85f85c9..b24874f1b4 100644
--- a/packages/svelte/tests/compiler-errors/samples/then-without-await/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/then-without-await/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'invalid-continuing-block-placement',
+		code: 'invalid_continuing_block_placement',
 		message:
 			'{:...} block is invalid at this position (did you forget to close the preceeding element or block?)',
 		position: [1, 1]
diff --git a/packages/svelte/tests/compiler-errors/samples/unclosed-attribute-self-close-tag/_config.js b/packages/svelte/tests/compiler-errors/samples/unclosed-attribute-self-close-tag/_config.js
index 2f4ec8835f..5a33a0c237 100644
--- a/packages/svelte/tests/compiler-errors/samples/unclosed-attribute-self-close-tag/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/unclosed-attribute-self-close-tag/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'unclosed-attribute-value',
+		code: 'unclosed_attribute_value',
 		message: 'Expected closing } character',
 		position: [19, 19]
 	}
diff --git a/packages/svelte/tests/compiler-errors/samples/unexpected-end-of-input-b/_config.js b/packages/svelte/tests/compiler-errors/samples/unexpected-end-of-input-b/_config.js
index e69ada8861..25dbf88c64 100644
--- a/packages/svelte/tests/compiler-errors/samples/unexpected-end-of-input-b/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/unexpected-end-of-input-b/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'unexpected-eof',
+		code: 'unexpected_eof',
 		message: 'Unexpected end of input',
 		position: [2, 2]
 	}
diff --git a/packages/svelte/tests/compiler-errors/samples/unexpected-end-of-input-c/_config.js b/packages/svelte/tests/compiler-errors/samples/unexpected-end-of-input-c/_config.js
index 47a1b49f03..edaeb89e40 100644
--- a/packages/svelte/tests/compiler-errors/samples/unexpected-end-of-input-c/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/unexpected-end-of-input-c/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'unexpected-eof',
+		code: 'unexpected_eof',
 		message: 'Unexpected end of input',
 		position: [1, 1]
 	}
diff --git a/packages/svelte/tests/compiler-errors/samples/unexpected-end-of-input/_config.js b/packages/svelte/tests/compiler-errors/samples/unexpected-end-of-input/_config.js
index d141ce161f..6ab0c7f716 100644
--- a/packages/svelte/tests/compiler-errors/samples/unexpected-end-of-input/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/unexpected-end-of-input/_config.js
@@ -3,7 +3,7 @@ import { test } from '../../test';
 export default test({
 	error: {
 		code: 'unclosed_element',
-		message: '<div> was left open',
+		message: '`<div>` was left open',
 		position: [0, 1]
 	}
 });
diff --git a/packages/svelte/tests/compiler-errors/samples/unmatched-closing-tag-autoclose-2/_config.js b/packages/svelte/tests/compiler-errors/samples/unmatched-closing-tag-autoclose-2/_config.js
index e0b8622711..824db2ae2e 100644
--- a/packages/svelte/tests/compiler-errors/samples/unmatched-closing-tag-autoclose-2/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/unmatched-closing-tag-autoclose-2/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'invalid-closing-tag',
+		code: 'invalid_closing_tag',
 		message: '</p> attempted to close an element that was not open',
 		position: [38, 38]
 	}
diff --git a/packages/svelte/tests/compiler-errors/samples/unmatched-closing-tag-autoclose/_config.js b/packages/svelte/tests/compiler-errors/samples/unmatched-closing-tag-autoclose/_config.js
index 38731fed64..bfd76bff4f 100644
--- a/packages/svelte/tests/compiler-errors/samples/unmatched-closing-tag-autoclose/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/unmatched-closing-tag-autoclose/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'invalid-closing-tag-after-autoclose',
+		code: 'invalid_closing_tag_after_autoclose',
 		message:
 			'</p> attempted to close element that was already automatically closed by <pre> (cannot nest <pre> inside <p>)',
 		position: [24, 24]
diff --git a/packages/svelte/tests/compiler-errors/samples/unmatched-closing-tag/_config.js b/packages/svelte/tests/compiler-errors/samples/unmatched-closing-tag/_config.js
index dd6995d832..6609a11e42 100644
--- a/packages/svelte/tests/compiler-errors/samples/unmatched-closing-tag/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/unmatched-closing-tag/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'invalid-closing-tag',
+		code: 'invalid_closing_tag',
 		message: '</div> attempted to close an element that was not open',
 		position: [0, 0]
 	}
diff --git a/packages/svelte/tests/compiler-errors/samples/void-closing/_config.js b/packages/svelte/tests/compiler-errors/samples/void-closing/_config.js
index 704d8c6029..360fcec971 100644
--- a/packages/svelte/tests/compiler-errors/samples/void-closing/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/void-closing/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'invalid-void-content',
+		code: 'invalid_void_content',
 		message: 'Void elements cannot have children or closing tags',
 		position: [23, 23]
 	}
diff --git a/packages/svelte/tests/compiler-errors/samples/window-children/_config.js b/packages/svelte/tests/compiler-errors/samples/window-children/_config.js
index 33b57bf5f6..a788c01ad5 100644
--- a/packages/svelte/tests/compiler-errors/samples/window-children/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/window-children/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'invalid-element-content',
+		code: 'invalid_element_content',
 		message: '<svelte:window> cannot have children',
 		position: [15, 15]
 	}
diff --git a/packages/svelte/tests/compiler-errors/samples/window-duplicate/_config.js b/packages/svelte/tests/compiler-errors/samples/window-duplicate/_config.js
index 9c068c0297..fed30e9475 100644
--- a/packages/svelte/tests/compiler-errors/samples/window-duplicate/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/window-duplicate/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'duplicate-svelte-element',
+		code: 'duplicate_svelte_element',
 		message: 'A component can only have one <svelte:window> element',
 		position: [17, 17]
 	}
diff --git a/packages/svelte/tests/compiler-errors/samples/window-inside-block/_config.js b/packages/svelte/tests/compiler-errors/samples/window-inside-block/_config.js
index 698c3813e6..36bda11a77 100644
--- a/packages/svelte/tests/compiler-errors/samples/window-inside-block/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/window-inside-block/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'invalid-svelte-element-placement',
+		code: 'invalid_svelte_element_placement',
 		message: '<svelte:window> tags cannot be inside elements or blocks',
 		position: [11, 11]
 	}
diff --git a/packages/svelte/tests/compiler-errors/samples/window-inside-element/_config.js b/packages/svelte/tests/compiler-errors/samples/window-inside-element/_config.js
index 04aba56e54..844353ac1b 100644
--- a/packages/svelte/tests/compiler-errors/samples/window-inside-element/_config.js
+++ b/packages/svelte/tests/compiler-errors/samples/window-inside-element/_config.js
@@ -2,7 +2,7 @@ import { test } from '../../test';
 
 export default test({
 	error: {
-		code: 'invalid-svelte-element-placement',
+		code: 'invalid_svelte_element_placement',
 		message: '<svelte:window> tags cannot be inside elements or blocks',
 		position: [7, 7]
 	}
diff --git a/packages/svelte/tests/validator/samples/action-on-component/errors.json b/packages/svelte/tests/validator/samples/action-on-component/errors.json
index 6516cf9108..f190f2282f 100644
--- a/packages/svelte/tests/validator/samples/action-on-component/errors.json
+++ b/packages/svelte/tests/validator/samples/action-on-component/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "invalid-component-directive",
+		"code": "invalid_component_directive",
 		"message": "This type of directive is not valid on components",
 		"start": {
 			"line": 7,
diff --git a/packages/svelte/tests/validator/samples/animation-duplicate/errors.json b/packages/svelte/tests/validator/samples/animation-duplicate/errors.json
index 2a1ba6b5ac..487196fc8f 100644
--- a/packages/svelte/tests/validator/samples/animation-duplicate/errors.json
+++ b/packages/svelte/tests/validator/samples/animation-duplicate/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "duplicate-animation",
+		"code": "duplicate_animation",
 		"message": "An element can only have one 'animate' directive",
 		"start": {
 			"line": 7,
diff --git a/packages/svelte/tests/validator/samples/animation-not-in-each/errors.json b/packages/svelte/tests/validator/samples/animation-not-in-each/errors.json
index d296c8994d..cbb4fab4c4 100644
--- a/packages/svelte/tests/validator/samples/animation-not-in-each/errors.json
+++ b/packages/svelte/tests/validator/samples/animation-not-in-each/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "invalid-animation",
+		"code": "invalid_animation",
 		"message": "An element that uses the animate directive must be the immediate child of a keyed each block",
 		"start": {
 			"line": 5,
diff --git a/packages/svelte/tests/validator/samples/animation-not-in-keyed-each/errors.json b/packages/svelte/tests/validator/samples/animation-not-in-keyed-each/errors.json
index 709ad5e196..4e4423dfa7 100644
--- a/packages/svelte/tests/validator/samples/animation-not-in-keyed-each/errors.json
+++ b/packages/svelte/tests/validator/samples/animation-not-in-keyed-each/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "invalid-animation",
+		"code": "invalid_animation",
 		"message": "An element that uses the animate directive must be used inside a keyed each block. Did you forget to add a key to your each block?",
 		"start": {
 			"line": 6,
diff --git a/packages/svelte/tests/validator/samples/animation-on-component/errors.json b/packages/svelte/tests/validator/samples/animation-on-component/errors.json
index eabf72bb02..f904517a89 100644
--- a/packages/svelte/tests/validator/samples/animation-on-component/errors.json
+++ b/packages/svelte/tests/validator/samples/animation-on-component/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "invalid-component-directive",
+		"code": "invalid_component_directive",
 		"message": "This type of directive is not valid on components",
 		"start": {
 			"line": 7,
diff --git a/packages/svelte/tests/validator/samples/animation-siblings/errors.json b/packages/svelte/tests/validator/samples/animation-siblings/errors.json
index 709f7006ce..46648d96fc 100644
--- a/packages/svelte/tests/validator/samples/animation-siblings/errors.json
+++ b/packages/svelte/tests/validator/samples/animation-siblings/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "invalid-animation",
+		"code": "invalid_animation",
 		"message": "An element that uses the animate directive must be the sole child of a keyed each block",
 		"start": {
 			"line": 6,
diff --git a/packages/svelte/tests/validator/samples/assignment-to-const-2/errors.json b/packages/svelte/tests/validator/samples/assignment-to-const-2/errors.json
index 1b74f51563..e4b6b6b329 100644
--- a/packages/svelte/tests/validator/samples/assignment-to-const-2/errors.json
+++ b/packages/svelte/tests/validator/samples/assignment-to-const-2/errors.json
@@ -1,7 +1,7 @@
 [
 	{
-		"code": "invalid-const-assignment",
-		"message": "Invalid assignment to const variable",
+		"code": "invalid_assignment",
+		"message": "Cannot assign to constant",
 		"start": {
 			"line": 13,
 			"column": 24
diff --git a/packages/svelte/tests/validator/samples/assignment-to-const-3/errors.json b/packages/svelte/tests/validator/samples/assignment-to-const-3/errors.json
index b00dd32495..7c92566f1f 100644
--- a/packages/svelte/tests/validator/samples/assignment-to-const-3/errors.json
+++ b/packages/svelte/tests/validator/samples/assignment-to-const-3/errors.json
@@ -1,7 +1,7 @@
 [
 	{
-		"code": "invalid-const-assignment",
-		"message": "Invalid assignment to const variable",
+		"code": "invalid_assignment",
+		"message": "Cannot assign to constant",
 		"start": {
 			"line": 14,
 			"column": 3
diff --git a/packages/svelte/tests/validator/samples/assignment-to-const-4/errors.json b/packages/svelte/tests/validator/samples/assignment-to-const-4/errors.json
index 1fcfaf2406..e714e99a38 100644
--- a/packages/svelte/tests/validator/samples/assignment-to-const-4/errors.json
+++ b/packages/svelte/tests/validator/samples/assignment-to-const-4/errors.json
@@ -1,7 +1,7 @@
 [
 	{
-		"code": "invalid-const-assignment",
-		"message": "Invalid assignment to const variable",
+		"code": "invalid_assignment",
+		"message": "Cannot assign to constant",
 		"start": {
 			"line": 17,
 			"column": 2
diff --git a/packages/svelte/tests/validator/samples/assignment-to-const-5/errors.json b/packages/svelte/tests/validator/samples/assignment-to-const-5/errors.json
index 9bff01645a..41002cd83e 100644
--- a/packages/svelte/tests/validator/samples/assignment-to-const-5/errors.json
+++ b/packages/svelte/tests/validator/samples/assignment-to-const-5/errors.json
@@ -1,7 +1,7 @@
 [
 	{
-		"code": "invalid-const-assignment",
-		"message": "Invalid assignment to const variable",
+		"code": "invalid_assignment",
+		"message": "Cannot assign to constant",
 		"start": {
 			"line": 3,
 			"column": 1
diff --git a/packages/svelte/tests/validator/samples/assignment-to-const-7/errors.json b/packages/svelte/tests/validator/samples/assignment-to-const-7/errors.json
index 02e5503b16..01c1aefb7e 100644
--- a/packages/svelte/tests/validator/samples/assignment-to-const-7/errors.json
+++ b/packages/svelte/tests/validator/samples/assignment-to-const-7/errors.json
@@ -1,7 +1,7 @@
 [
 	{
-		"code": "invalid-const-assignment",
-		"message": "Invalid assignment to const variable",
+		"code": "invalid_assignment",
+		"message": "Cannot assign to constant",
 		"start": {
 			"line": 3,
 			"column": 1
diff --git a/packages/svelte/tests/validator/samples/assignment-to-const/errors.json b/packages/svelte/tests/validator/samples/assignment-to-const/errors.json
index 88d6b728b9..6963a3737b 100644
--- a/packages/svelte/tests/validator/samples/assignment-to-const/errors.json
+++ b/packages/svelte/tests/validator/samples/assignment-to-const/errors.json
@@ -1,7 +1,7 @@
 [
 	{
-		"code": "invalid-const-assignment",
-		"message": "Invalid assignment to const variable",
+		"code": "invalid_assignment",
+		"message": "Cannot assign to constant",
 		"start": {
 			"line": 16,
 			"column": 2
diff --git a/packages/svelte/tests/validator/samples/attribute-expected-equals/errors.json b/packages/svelte/tests/validator/samples/attribute-expected-equals/errors.json
index deb2331622..f3b90628ab 100644
--- a/packages/svelte/tests/validator/samples/attribute-expected-equals/errors.json
+++ b/packages/svelte/tests/validator/samples/attribute-expected-equals/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "expected-token",
+		"code": "expected_token",
 		"message": "Expected token =",
 		"start": {
 			"line": 5,
diff --git a/packages/svelte/tests/validator/samples/attribute-invalid-name-2/errors.json b/packages/svelte/tests/validator/samples/attribute-invalid-name-2/errors.json
index 0e4afb3009..f99b36ff36 100644
--- a/packages/svelte/tests/validator/samples/attribute-invalid-name-2/errors.json
+++ b/packages/svelte/tests/validator/samples/attribute-invalid-name-2/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "invalid-attribute-name",
+		"code": "invalid_attribute_name",
 		"message": "'3aa' is not a valid attribute name",
 		"start": {
 			"line": 1,
diff --git a/packages/svelte/tests/validator/samples/attribute-invalid-name-3/errors.json b/packages/svelte/tests/validator/samples/attribute-invalid-name-3/errors.json
index c13a5c5b90..7c49600412 100644
--- a/packages/svelte/tests/validator/samples/attribute-invalid-name-3/errors.json
+++ b/packages/svelte/tests/validator/samples/attribute-invalid-name-3/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "invalid-attribute-name",
+		"code": "invalid_attribute_name",
 		"message": "'a*a' is not a valid attribute name",
 		"start": {
 			"line": 1,
diff --git a/packages/svelte/tests/validator/samples/attribute-invalid-name-4/errors.json b/packages/svelte/tests/validator/samples/attribute-invalid-name-4/errors.json
index 4cccb34b28..693c080dd1 100644
--- a/packages/svelte/tests/validator/samples/attribute-invalid-name-4/errors.json
+++ b/packages/svelte/tests/validator/samples/attribute-invalid-name-4/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "invalid-attribute-name",
+		"code": "invalid_attribute_name",
 		"message": "'-a' is not a valid attribute name",
 		"start": {
 			"line": 1,
diff --git a/packages/svelte/tests/validator/samples/attribute-invalid-name-5/errors.json b/packages/svelte/tests/validator/samples/attribute-invalid-name-5/errors.json
index b99bb946ae..4a5b59bbe8 100644
--- a/packages/svelte/tests/validator/samples/attribute-invalid-name-5/errors.json
+++ b/packages/svelte/tests/validator/samples/attribute-invalid-name-5/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "invalid-attribute-name",
+		"code": "invalid_attribute_name",
 		"message": "'a;' is not a valid attribute name",
 		"start": {
 			"line": 1,
diff --git a/packages/svelte/tests/validator/samples/attribute-invalid-name/errors.json b/packages/svelte/tests/validator/samples/attribute-invalid-name/errors.json
index 5b674a6f7d..6e9e2dc0f1 100644
--- a/packages/svelte/tests/validator/samples/attribute-invalid-name/errors.json
+++ b/packages/svelte/tests/validator/samples/attribute-invalid-name/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "invalid-attribute-name",
+		"code": "invalid_attribute_name",
 		"message": "'}' is not a valid attribute name",
 		"start": {
 			"line": 1,
diff --git a/packages/svelte/tests/validator/samples/binding-await-catch/errors.json b/packages/svelte/tests/validator/samples/binding-await-catch/errors.json
index 8cdef47534..c2acbb2e8d 100644
--- a/packages/svelte/tests/validator/samples/binding-await-catch/errors.json
+++ b/packages/svelte/tests/validator/samples/binding-await-catch/errors.json
@@ -1,8 +1,14 @@
 [
 	{
-		"code": "invalid-const-assignment",
+		"code": "invalid_assignment",
 		"message": "Invalid binding to const variable ($derived values, let: directives, :then/:catch variables and @const declarations count as const)",
-		"start": { "line": 6, "column": 9 },
-		"end": { "line": 6, "column": 27 }
+		"start": {
+			"line": 6,
+			"column": 9
+		},
+		"end": {
+			"line": 6,
+			"column": 27
+		}
 	}
 ]
diff --git a/packages/svelte/tests/validator/samples/binding-await-then-2/errors.json b/packages/svelte/tests/validator/samples/binding-await-then-2/errors.json
index 050d02f42b..f0f4a7a3fd 100644
--- a/packages/svelte/tests/validator/samples/binding-await-then-2/errors.json
+++ b/packages/svelte/tests/validator/samples/binding-await-then-2/errors.json
@@ -1,8 +1,14 @@
 [
 	{
-		"code": "invalid-const-assignment",
+		"code": "invalid_assignment",
 		"message": "Invalid binding to const variable ($derived values, let: directives, :then/:catch variables and @const declarations count as const)",
-		"start": { "line": 6, "column": 9 },
-		"end": { "line": 6, "column": 19 }
+		"start": {
+			"line": 6,
+			"column": 9
+		},
+		"end": {
+			"line": 6,
+			"column": 19
+		}
 	}
 ]
diff --git a/packages/svelte/tests/validator/samples/binding-await-then/errors.json b/packages/svelte/tests/validator/samples/binding-await-then/errors.json
index ec6467441e..c4f6009c78 100644
--- a/packages/svelte/tests/validator/samples/binding-await-then/errors.json
+++ b/packages/svelte/tests/validator/samples/binding-await-then/errors.json
@@ -1,8 +1,14 @@
 [
 	{
-		"code": "invalid-const-assignment",
+		"code": "invalid_assignment",
 		"message": "Invalid binding to const variable ($derived values, let: directives, :then/:catch variables and @const declarations count as const)",
-		"start": { "line": 5, "column": 9 },
-		"end": { "line": 5, "column": 19 }
+		"start": {
+			"line": 5,
+			"column": 9
+		},
+		"end": {
+			"line": 5,
+			"column": 19
+		}
 	}
 ]
diff --git a/packages/svelte/tests/validator/samples/binding-const/errors.json b/packages/svelte/tests/validator/samples/binding-const/errors.json
index cf3522eef1..213a0808f7 100644
--- a/packages/svelte/tests/validator/samples/binding-const/errors.json
+++ b/packages/svelte/tests/validator/samples/binding-const/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "invalid-const-assignment",
+		"code": "invalid_assignment",
 		"message": "Invalid binding to const variable",
 		"start": {
 			"line": 5,
diff --git a/packages/svelte/tests/validator/samples/binding-dimensions-svg/errors.json b/packages/svelte/tests/validator/samples/binding-dimensions-svg/errors.json
index b1969bfd5f..4d3819453c 100644
--- a/packages/svelte/tests/validator/samples/binding-dimensions-svg/errors.json
+++ b/packages/svelte/tests/validator/samples/binding-dimensions-svg/errors.json
@@ -1,7 +1,7 @@
 [
 	{
-		"code": "invalid-binding",
-		"message": "'offsetWidth' binding can only be used with non-<svg> elements. Use 'clientWidth' for <svg> instead",
+		"code": "bind_invalid_target",
+		"message": "`bind:offsetWidth` can only be used with non-<svg> elements. Use 'clientWidth' for <svg> instead",
 		"start": {
 			"line": 5,
 			"column": 5
diff --git a/packages/svelte/tests/validator/samples/binding-input-checked/errors.json b/packages/svelte/tests/validator/samples/binding-input-checked/errors.json
index 50abdd6df9..574b25e06f 100644
--- a/packages/svelte/tests/validator/samples/binding-input-checked/errors.json
+++ b/packages/svelte/tests/validator/samples/binding-input-checked/errors.json
@@ -1,7 +1,7 @@
 [
 	{
-		"code": "invalid-binding",
-		"message": "'checked' binding can only be used with <input type=\"checkbox\">",
+		"code": "bind_invalid_target",
+		"message": "`bind:checked` can only be used with <input type=\"checkbox\">",
 		"start": {
 			"line": 5,
 			"column": 7
diff --git a/packages/svelte/tests/validator/samples/binding-input-type-boolean/errors.json b/packages/svelte/tests/validator/samples/binding-input-type-boolean/errors.json
index 6a4807a7b1..87a3f6f8ea 100644
--- a/packages/svelte/tests/validator/samples/binding-input-type-boolean/errors.json
+++ b/packages/svelte/tests/validator/samples/binding-input-type-boolean/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "invalid-type-attribute",
+		"code": "invalid_type_attribute",
 		"message": "'type' attribute must be a static text value if input uses two-way binding",
 		"start": {
 			"line": 5,
diff --git a/packages/svelte/tests/validator/samples/binding-invalid-foreign-namespace/errors.json b/packages/svelte/tests/validator/samples/binding-invalid-foreign-namespace/errors.json
index 7b6d4f51db..0049ed5359 100644
--- a/packages/svelte/tests/validator/samples/binding-invalid-foreign-namespace/errors.json
+++ b/packages/svelte/tests/validator/samples/binding-invalid-foreign-namespace/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "invalid-binding",
+		"code": "bind_invalid_target",
 		"message": "'value' is not a valid binding. Foreign elements only support bind:this",
 		"start": {
 			"line": 6,
diff --git a/packages/svelte/tests/validator/samples/binding-invalid-on-element-2/errors.json b/packages/svelte/tests/validator/samples/binding-invalid-on-element-2/errors.json
index c379a94d5a..92111a4ec2 100644
--- a/packages/svelte/tests/validator/samples/binding-invalid-on-element-2/errors.json
+++ b/packages/svelte/tests/validator/samples/binding-invalid-on-element-2/errors.json
@@ -1,7 +1,7 @@
 [
 	{
-		"code": "invalid-binding",
-		"message": "'open' binding can only be used with <details>",
+		"code": "bind_invalid_target",
+		"message": "`bind:open` can only be used with <details>",
 		"start": {
 			"line": 5,
 			"column": 5
diff --git a/packages/svelte/tests/validator/samples/binding-invalid-on-element/errors.json b/packages/svelte/tests/validator/samples/binding-invalid-on-element/errors.json
index 9898ad8fa5..6626afc1d0 100644
--- a/packages/svelte/tests/validator/samples/binding-invalid-on-element/errors.json
+++ b/packages/svelte/tests/validator/samples/binding-invalid-on-element/errors.json
@@ -1,7 +1,7 @@
 [
 	{
-		"code": "invalid-binding",
-		"message": "'value' binding can only be used with <input>, <textarea>, <select>",
+		"code": "bind_invalid_target",
+		"message": "`bind:value` can only be used with <input>, <textarea>, <select>",
 		"start": {
 			"line": 5,
 			"column": 5
diff --git a/packages/svelte/tests/validator/samples/binding-invalid-value-global/errors.json b/packages/svelte/tests/validator/samples/binding-invalid-value-global/errors.json
index cff83b012e..82e86887bd 100644
--- a/packages/svelte/tests/validator/samples/binding-invalid-value-global/errors.json
+++ b/packages/svelte/tests/validator/samples/binding-invalid-value-global/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "invalid-binding-value",
+		"code": "invalid_binding_value",
 		"message": "Can only bind to state or props",
 		"start": {
 			"line": 4,
diff --git a/packages/svelte/tests/validator/samples/binding-invalid-value/errors.json b/packages/svelte/tests/validator/samples/binding-invalid-value/errors.json
index a6e53e4e36..34026c52ac 100644
--- a/packages/svelte/tests/validator/samples/binding-invalid-value/errors.json
+++ b/packages/svelte/tests/validator/samples/binding-invalid-value/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "invalid-binding-value",
+		"code": "invalid_binding_value",
 		"message": "Can only bind to state or props",
 		"start": {
 			"line": 2,
diff --git a/packages/svelte/tests/validator/samples/binding-invalid/errors.json b/packages/svelte/tests/validator/samples/binding-invalid/errors.json
index fdd0ada258..280360c625 100644
--- a/packages/svelte/tests/validator/samples/binding-invalid/errors.json
+++ b/packages/svelte/tests/validator/samples/binding-invalid/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "invalid-binding",
+		"code": "bind_invalid_target",
 		"message": "'whatever' is not a valid binding",
 		"start": {
 			"line": 5,
diff --git a/packages/svelte/tests/validator/samples/binding-let/errors.json b/packages/svelte/tests/validator/samples/binding-let/errors.json
index c6c734cf91..a133cbd1ea 100644
--- a/packages/svelte/tests/validator/samples/binding-let/errors.json
+++ b/packages/svelte/tests/validator/samples/binding-let/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "invalid-const-assignment",
+		"code": "invalid_assignment",
 		"message": "Invalid binding to const variable ($derived values, let: directives, :then/:catch variables and @const declarations count as const)",
 		"start": {
 			"line": 6,
diff --git a/packages/svelte/tests/validator/samples/binding-select-multiple-dynamic/errors.json b/packages/svelte/tests/validator/samples/binding-select-multiple-dynamic/errors.json
index 95ab7f91d4..b280929333 100644
--- a/packages/svelte/tests/validator/samples/binding-select-multiple-dynamic/errors.json
+++ b/packages/svelte/tests/validator/samples/binding-select-multiple-dynamic/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "invalid-multiple-attribute",
+		"code": "invalid_multiple_attribute",
 		"message": "'multiple' attribute must be static if select uses two-way binding",
 		"start": {
 			"line": 6,
diff --git a/packages/svelte/tests/validator/samples/component-event-modifiers-invalid/errors.json b/packages/svelte/tests/validator/samples/component-event-modifiers-invalid/errors.json
index 3edd0059a3..275f5c5b07 100644
--- a/packages/svelte/tests/validator/samples/component-event-modifiers-invalid/errors.json
+++ b/packages/svelte/tests/validator/samples/component-event-modifiers-invalid/errors.json
@@ -1,7 +1,7 @@
 [
 	{
 		"message": "Event modifiers other than 'once' can only be used on DOM elements",
-		"code": "invalid-event-modifier",
+		"code": "invalid_event_modifier",
 		"start": {
 			"line": 6,
 			"column": 8
diff --git a/packages/svelte/tests/validator/samples/component-invalid-style-directive/errors.json b/packages/svelte/tests/validator/samples/component-invalid-style-directive/errors.json
index 6c37a888ff..3eeb050cdb 100644
--- a/packages/svelte/tests/validator/samples/component-invalid-style-directive/errors.json
+++ b/packages/svelte/tests/validator/samples/component-invalid-style-directive/errors.json
@@ -1,8 +1,14 @@
 [
 	{
-		"code": "invalid-component-directive",
+		"code": "invalid_component_directive",
 		"message": "This type of directive is not valid on components",
-		"start": { "line": 7, "column": 19 },
-		"end": { "line": 7, "column": 36 }
+		"start": {
+			"line": 7,
+			"column": 19
+		},
+		"end": {
+			"line": 7,
+			"column": 36
+		}
 	}
 ]
diff --git a/packages/svelte/tests/validator/samples/component-slot-default-reserved/errors.json b/packages/svelte/tests/validator/samples/component-slot-default-reserved/errors.json
index 5347d4737f..0f4af538a4 100644
--- a/packages/svelte/tests/validator/samples/component-slot-default-reserved/errors.json
+++ b/packages/svelte/tests/validator/samples/component-slot-default-reserved/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "invalid-slot-name",
+		"code": "invalid_slot_name",
 		"message": "default is a reserved word — it cannot be used as a slot name",
 		"start": {
 			"line": 1,
diff --git a/packages/svelte/tests/validator/samples/component-slot-dynamic-attribute/errors.json b/packages/svelte/tests/validator/samples/component-slot-dynamic-attribute/errors.json
index 9194e8aa9b..238bd48d90 100644
--- a/packages/svelte/tests/validator/samples/component-slot-dynamic-attribute/errors.json
+++ b/packages/svelte/tests/validator/samples/component-slot-dynamic-attribute/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "invalid-slot-attribute",
+		"code": "invalid_slot_attribute",
 		"message": "slot attribute must be a static value",
 		"start": {
 			"line": 6,
diff --git a/packages/svelte/tests/validator/samples/component-slot-dynamic/errors.json b/packages/svelte/tests/validator/samples/component-slot-dynamic/errors.json
index 963cb1f40d..0c08ef2dad 100644
--- a/packages/svelte/tests/validator/samples/component-slot-dynamic/errors.json
+++ b/packages/svelte/tests/validator/samples/component-slot-dynamic/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "invalid-slot-name",
+		"code": "invalid_slot_name",
 		"message": "slot attribute must be a static value",
 		"start": {
 			"line": 1,
diff --git a/packages/svelte/tests/validator/samples/component-slotted-custom-element-2/errors.json b/packages/svelte/tests/validator/samples/component-slotted-custom-element-2/errors.json
index da10838a69..63960b846b 100644
--- a/packages/svelte/tests/validator/samples/component-slotted-custom-element-2/errors.json
+++ b/packages/svelte/tests/validator/samples/component-slotted-custom-element-2/errors.json
@@ -1,8 +1,14 @@
 [
 	{
-		"code": "invalid-slot-placement",
+		"code": "invalid_slot_placement",
 		"message": "Element with a slot='...' attribute must be a child of a component or a descendant of a custom element",
-		"start": { "line": 10, "column": 9 },
-		"end": { "line": 10, "column": 19 }
+		"start": {
+			"line": 10,
+			"column": 9
+		},
+		"end": {
+			"line": 10,
+			"column": 19
+		}
 	}
 ]
diff --git a/packages/svelte/tests/validator/samples/component-slotted-each-block/errors.json b/packages/svelte/tests/validator/samples/component-slotted-each-block/errors.json
index 12d2407540..b04ef9e4aa 100644
--- a/packages/svelte/tests/validator/samples/component-slotted-each-block/errors.json
+++ b/packages/svelte/tests/validator/samples/component-slotted-each-block/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "invalid-slot-placement",
+		"code": "invalid_slot_placement",
 		"message": "Element with a slot='...' attribute must be a child of a component or a descendant of a custom element",
 		"start": {
 			"line": 7,
diff --git a/packages/svelte/tests/validator/samples/component-slotted-if-block/errors.json b/packages/svelte/tests/validator/samples/component-slotted-if-block/errors.json
index 12d2407540..b04ef9e4aa 100644
--- a/packages/svelte/tests/validator/samples/component-slotted-if-block/errors.json
+++ b/packages/svelte/tests/validator/samples/component-slotted-if-block/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "invalid-slot-placement",
+		"code": "invalid_slot_placement",
 		"message": "Element with a slot='...' attribute must be a child of a component or a descendant of a custom element",
 		"start": {
 			"line": 7,
diff --git a/packages/svelte/tests/validator/samples/const-tag-conflict-1/errors.json b/packages/svelte/tests/validator/samples/const-tag-conflict-1/errors.json
index 78beca08c7..d63fcd88e7 100644
--- a/packages/svelte/tests/validator/samples/const-tag-conflict-1/errors.json
+++ b/packages/svelte/tests/validator/samples/const-tag-conflict-1/errors.json
@@ -1,8 +1,14 @@
 [
 	{
-		"code": "duplicate-declaration",
+		"code": "duplicate_declaration",
 		"message": "'a' has already been declared",
-		"start": { "line": 7, "column": 10 },
-		"end": { "line": 7, "column": 11 }
+		"start": {
+			"line": 7,
+			"column": 10
+		},
+		"end": {
+			"line": 7,
+			"column": 11
+		}
 	}
 ]
diff --git a/packages/svelte/tests/validator/samples/const-tag-conflict-2/errors.json b/packages/svelte/tests/validator/samples/const-tag-conflict-2/errors.json
index dc3c1322c7..f7df4a21c4 100644
--- a/packages/svelte/tests/validator/samples/const-tag-conflict-2/errors.json
+++ b/packages/svelte/tests/validator/samples/const-tag-conflict-2/errors.json
@@ -1,8 +1,14 @@
 [
 	{
-		"code": "duplicate-declaration",
+		"code": "duplicate_declaration",
 		"message": "'item' has already been declared",
-		"start": { "line": 6, "column": 10 },
-		"end": { "line": 6, "column": 14 }
+		"start": {
+			"line": 6,
+			"column": 10
+		},
+		"end": {
+			"line": 6,
+			"column": 14
+		}
 	}
 ]
diff --git a/packages/svelte/tests/validator/samples/const-tag-placement-1/errors.json b/packages/svelte/tests/validator/samples/const-tag-placement-1/errors.json
index 66ff86663f..4db0868c16 100644
--- a/packages/svelte/tests/validator/samples/const-tag-placement-1/errors.json
+++ b/packages/svelte/tests/validator/samples/const-tag-placement-1/errors.json
@@ -1,8 +1,14 @@
 [
 	{
-		"code": "invalid-const-placement",
+		"code": "invalid_const_placement",
 		"message": "{@const} must be the immediate child of {#snippet}, {#if}, {:else if}, {:else}, {#each}, {:then}, {:catch}, <svelte:fragment> or <Component>",
-		"start": { "line": 5, "column": 0 },
-		"end": { "line": 5, "column": 18 }
+		"start": {
+			"line": 5,
+			"column": 0
+		},
+		"end": {
+			"line": 5,
+			"column": 18
+		}
 	}
 ]
diff --git a/packages/svelte/tests/validator/samples/const-tag-placement-2/errors.json b/packages/svelte/tests/validator/samples/const-tag-placement-2/errors.json
index 6c14fdbaf7..33b24f369e 100644
--- a/packages/svelte/tests/validator/samples/const-tag-placement-2/errors.json
+++ b/packages/svelte/tests/validator/samples/const-tag-placement-2/errors.json
@@ -1,8 +1,14 @@
 [
 	{
-		"code": "invalid-const-placement",
+		"code": "invalid_const_placement",
 		"message": "{@const} must be the immediate child of {#snippet}, {#if}, {:else if}, {:else}, {#each}, {:then}, {:catch}, <svelte:fragment> or <Component>",
-		"start": { "line": 7, "column": 4 },
-		"end": { "line": 7, "column": 18 }
+		"start": {
+			"line": 7,
+			"column": 4
+		},
+		"end": {
+			"line": 7,
+			"column": 18
+		}
 	}
 ]
diff --git a/packages/svelte/tests/validator/samples/const-tag-readonly-1/errors.json b/packages/svelte/tests/validator/samples/const-tag-readonly-1/errors.json
index abe738f6cf..3da55f85bc 100644
--- a/packages/svelte/tests/validator/samples/const-tag-readonly-1/errors.json
+++ b/packages/svelte/tests/validator/samples/const-tag-readonly-1/errors.json
@@ -1,8 +1,14 @@
 [
 	{
-		"code": "invalid-const-assignment",
-		"message": "Invalid assignment to const variable ($derived values, let: directives, :then/:catch variables and @const declarations count as const)",
-		"start": { "line": 7, "column": 26 },
-		"end": { "line": 7, "column": 30 }
+		"code": "invalid_assignment",
+		"message": "Cannot assign to constant ($derived values, let: directives, :then/:catch variables and @const declarations count as const)",
+		"start": {
+			"line": 7,
+			"column": 26
+		},
+		"end": {
+			"line": 7,
+			"column": 30
+		}
 	}
 ]
diff --git a/packages/svelte/tests/validator/samples/const-tag-readonly-2/errors.json b/packages/svelte/tests/validator/samples/const-tag-readonly-2/errors.json
index a8c60a8b56..eb6c7390aa 100644
--- a/packages/svelte/tests/validator/samples/const-tag-readonly-2/errors.json
+++ b/packages/svelte/tests/validator/samples/const-tag-readonly-2/errors.json
@@ -1,8 +1,14 @@
 [
 	{
-		"code": "invalid-const-assignment",
+		"code": "invalid_assignment",
 		"message": "Invalid binding to const variable ($derived values, let: directives, :then/:catch variables and @const declarations count as const)",
-		"start": { "line": 7, "column": 9 },
-		"end": { "line": 7, "column": 23 }
+		"start": {
+			"line": 7,
+			"column": 9
+		},
+		"end": {
+			"line": 7,
+			"column": 23
+		}
 	}
 ]
diff --git a/packages/svelte/tests/validator/samples/contenteditable-dynamic/errors.json b/packages/svelte/tests/validator/samples/contenteditable-dynamic/errors.json
index 27cc3e98c7..285a6f921d 100644
--- a/packages/svelte/tests/validator/samples/contenteditable-dynamic/errors.json
+++ b/packages/svelte/tests/validator/samples/contenteditable-dynamic/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "dynamic-contenteditable-attribute",
+		"code": "dynamic_contenteditable_attribute",
 		"message": "'contenteditable' attribute cannot be dynamic if element uses two-way binding",
 		"start": {
 			"line": 11,
diff --git a/packages/svelte/tests/validator/samples/contenteditable-missing/errors.json b/packages/svelte/tests/validator/samples/contenteditable-missing/errors.json
index 24a072dac8..616c45021b 100644
--- a/packages/svelte/tests/validator/samples/contenteditable-missing/errors.json
+++ b/packages/svelte/tests/validator/samples/contenteditable-missing/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "missing-contenteditable-attribute",
+		"code": "missing_contenteditable_attribute",
 		"message": "'contenteditable' attribute is required for textContent, innerHTML and innerText two-way bindings",
 		"start": {
 			"line": 4,
diff --git a/packages/svelte/tests/validator/samples/css-invalid-combinator-selector-1/errors.json b/packages/svelte/tests/validator/samples/css-invalid-combinator-selector-1/errors.json
index d49bf7437a..eccbf62094 100644
--- a/packages/svelte/tests/validator/samples/css-invalid-combinator-selector-1/errors.json
+++ b/packages/svelte/tests/validator/samples/css-invalid-combinator-selector-1/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "invalid-css-selector",
+		"code": "invalid_css_selector",
 		"message": "Invalid selector",
 		"start": {
 			"line": 10,
diff --git a/packages/svelte/tests/validator/samples/css-invalid-combinator-selector-2/errors.json b/packages/svelte/tests/validator/samples/css-invalid-combinator-selector-2/errors.json
index 2fdf3e96d1..37cfb99c87 100644
--- a/packages/svelte/tests/validator/samples/css-invalid-combinator-selector-2/errors.json
+++ b/packages/svelte/tests/validator/samples/css-invalid-combinator-selector-2/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "invalid-css-selector",
+		"code": "invalid_css_selector",
 		"message": "Invalid selector",
 		"start": {
 			"line": 8,
diff --git a/packages/svelte/tests/validator/samples/css-invalid-combinator-selector-3/errors.json b/packages/svelte/tests/validator/samples/css-invalid-combinator-selector-3/errors.json
index b355260623..74fd26a692 100644
--- a/packages/svelte/tests/validator/samples/css-invalid-combinator-selector-3/errors.json
+++ b/packages/svelte/tests/validator/samples/css-invalid-combinator-selector-3/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "invalid-css-selector",
+		"code": "invalid_css_selector",
 		"message": "Invalid selector",
 		"start": {
 			"line": 5,
diff --git a/packages/svelte/tests/validator/samples/css-invalid-combinator-selector-4/errors.json b/packages/svelte/tests/validator/samples/css-invalid-combinator-selector-4/errors.json
index aab0a130c7..24f83fee73 100644
--- a/packages/svelte/tests/validator/samples/css-invalid-combinator-selector-4/errors.json
+++ b/packages/svelte/tests/validator/samples/css-invalid-combinator-selector-4/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "invalid-css-selector",
+		"code": "invalid_css_selector",
 		"message": "Invalid selector",
 		"start": {
 			"line": 4,
diff --git a/packages/svelte/tests/validator/samples/css-invalid-global-placement-2/errors.json b/packages/svelte/tests/validator/samples/css-invalid-global-placement-2/errors.json
index 1d359c01b3..1a11759e43 100644
--- a/packages/svelte/tests/validator/samples/css-invalid-global-placement-2/errors.json
+++ b/packages/svelte/tests/validator/samples/css-invalid-global-placement-2/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "invalid-css-global-placement",
+		"code": "invalid_css_global_placement",
 		"message": ":global(...) can be at the start or end of a selector sequence, but not in the middle",
 		"start": {
 			"line": 8,
diff --git a/packages/svelte/tests/validator/samples/css-invalid-global-placement-3/errors.json b/packages/svelte/tests/validator/samples/css-invalid-global-placement-3/errors.json
index 53e24d8d81..14fe638188 100644
--- a/packages/svelte/tests/validator/samples/css-invalid-global-placement-3/errors.json
+++ b/packages/svelte/tests/validator/samples/css-invalid-global-placement-3/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "invalid-css-global-placement",
+		"code": "invalid_css_global_placement",
 		"message": ":global(...) can be at the start or end of a selector sequence, but not in the middle",
 		"start": {
 			"line": 5,
diff --git a/packages/svelte/tests/validator/samples/css-invalid-global-placement-4/errors.json b/packages/svelte/tests/validator/samples/css-invalid-global-placement-4/errors.json
index fcc96361dd..539d91fb4d 100644
--- a/packages/svelte/tests/validator/samples/css-invalid-global-placement-4/errors.json
+++ b/packages/svelte/tests/validator/samples/css-invalid-global-placement-4/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "invalid-css-global-selector-list",
+		"code": "invalid_css_global_selector_list",
 		"message": ":global(...) must not contain type or universal selectors when used in a compound selector",
 		"start": {
 			"line": 2,
diff --git a/packages/svelte/tests/validator/samples/css-invalid-global-placement-5/errors.json b/packages/svelte/tests/validator/samples/css-invalid-global-placement-5/errors.json
index fbbdefb60e..a3a6a13b77 100644
--- a/packages/svelte/tests/validator/samples/css-invalid-global-placement-5/errors.json
+++ b/packages/svelte/tests/validator/samples/css-invalid-global-placement-5/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "invalid-css-global-selector-list",
+		"code": "invalid_css_global_selector_list",
 		"message": ":global(...) must not contain type or universal selectors when used in a compound selector",
 		"start": {
 			"line": 2,
diff --git a/packages/svelte/tests/validator/samples/css-invalid-global-placement-6/errors.json b/packages/svelte/tests/validator/samples/css-invalid-global-placement-6/errors.json
index 2b03fa8c2b..008a8ec266 100644
--- a/packages/svelte/tests/validator/samples/css-invalid-global-placement-6/errors.json
+++ b/packages/svelte/tests/validator/samples/css-invalid-global-placement-6/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "invalid-css-global-selector-list",
+		"code": "invalid_css_global_selector_list",
 		"message": ":global(...) must not contain type or universal selectors when used in a compound selector",
 		"start": {
 			"line": 5,
diff --git a/packages/svelte/tests/validator/samples/css-invalid-global-placement/errors.json b/packages/svelte/tests/validator/samples/css-invalid-global-placement/errors.json
index 7ba32a53fb..a2c76f2366 100644
--- a/packages/svelte/tests/validator/samples/css-invalid-global-placement/errors.json
+++ b/packages/svelte/tests/validator/samples/css-invalid-global-placement/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "invalid-css-global-placement",
+		"code": "invalid_css_global_placement",
 		"message": ":global(...) can be at the start or end of a selector sequence, but not in the middle",
 		"start": {
 			"line": 2,
diff --git a/packages/svelte/tests/validator/samples/css-invalid-global-selector-2/errors.json b/packages/svelte/tests/validator/samples/css-invalid-global-selector-2/errors.json
index 36b3ec4753..e6952aca16 100644
--- a/packages/svelte/tests/validator/samples/css-invalid-global-selector-2/errors.json
+++ b/packages/svelte/tests/validator/samples/css-invalid-global-selector-2/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "invalid-css-global-selector",
+		"code": "invalid_css_global_selector",
 		"message": ":global(...) must contain exactly one selector",
 		"start": {
 			"line": 11,
diff --git a/packages/svelte/tests/validator/samples/css-invalid-global-selector-3/errors.json b/packages/svelte/tests/validator/samples/css-invalid-global-selector-3/errors.json
index f4a75dcb17..5eaaee69d3 100644
--- a/packages/svelte/tests/validator/samples/css-invalid-global-selector-3/errors.json
+++ b/packages/svelte/tests/validator/samples/css-invalid-global-selector-3/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "invalid-css-global-selector",
+		"code": "invalid_css_global_selector",
 		"message": ":global(...) must contain exactly one selector",
 		"start": {
 			"line": 5,
diff --git a/packages/svelte/tests/validator/samples/css-invalid-global-selector-4/errors.json b/packages/svelte/tests/validator/samples/css-invalid-global-selector-4/errors.json
index a6ae2d595b..d3f84026d6 100644
--- a/packages/svelte/tests/validator/samples/css-invalid-global-selector-4/errors.json
+++ b/packages/svelte/tests/validator/samples/css-invalid-global-selector-4/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "invalid-css-global-selector",
+		"code": "invalid_css_global_selector",
 		"message": ":global(...) must contain exactly one selector",
 		"start": {
 			"line": 2,
diff --git a/packages/svelte/tests/validator/samples/css-invalid-global-selector-5/errors.json b/packages/svelte/tests/validator/samples/css-invalid-global-selector-5/errors.json
index 5ac729aa23..06ad62ef10 100644
--- a/packages/svelte/tests/validator/samples/css-invalid-global-selector-5/errors.json
+++ b/packages/svelte/tests/validator/samples/css-invalid-global-selector-5/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "invalid-css-global-selector",
+		"code": "invalid_css_global_selector",
 		"message": ":global(...) must contain exactly one selector",
 		"start": {
 			"line": 5,
diff --git a/packages/svelte/tests/validator/samples/css-invalid-global-selector-6/errors.json b/packages/svelte/tests/validator/samples/css-invalid-global-selector-6/errors.json
index 5ac729aa23..06ad62ef10 100644
--- a/packages/svelte/tests/validator/samples/css-invalid-global-selector-6/errors.json
+++ b/packages/svelte/tests/validator/samples/css-invalid-global-selector-6/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "invalid-css-global-selector",
+		"code": "invalid_css_global_selector",
 		"message": ":global(...) must contain exactly one selector",
 		"start": {
 			"line": 5,
diff --git a/packages/svelte/tests/validator/samples/css-invalid-global-selector-list/errors.json b/packages/svelte/tests/validator/samples/css-invalid-global-selector-list/errors.json
index 25399f6369..41fc6235e2 100644
--- a/packages/svelte/tests/validator/samples/css-invalid-global-selector-list/errors.json
+++ b/packages/svelte/tests/validator/samples/css-invalid-global-selector-list/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "invalid-css-global-selector-list",
+		"code": "invalid_css_global_selector_list",
 		"message": ":global(...) must not contain type or universal selectors when used in a compound selector",
 		"start": {
 			"line": 20,
diff --git a/packages/svelte/tests/validator/samples/css-invalid-global-selector/errors.json b/packages/svelte/tests/validator/samples/css-invalid-global-selector/errors.json
index 40bae7d4d7..50dfec051b 100644
--- a/packages/svelte/tests/validator/samples/css-invalid-global-selector/errors.json
+++ b/packages/svelte/tests/validator/samples/css-invalid-global-selector/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "invalid-css-global-selector",
+		"code": "invalid_css_global_selector",
 		"message": ":global(...) must contain exactly one selector",
 		"start": {
 			"line": 11,
diff --git a/packages/svelte/tests/validator/samples/css-invalid-type-selector-placement/errors.json b/packages/svelte/tests/validator/samples/css-invalid-type-selector-placement/errors.json
index f58f92d6ee..d5a2602fb6 100644
--- a/packages/svelte/tests/validator/samples/css-invalid-type-selector-placement/errors.json
+++ b/packages/svelte/tests/validator/samples/css-invalid-type-selector-placement/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "invalid-css-type-selector-placement",
+		"code": "invalid_css_type_selector_placement",
 		"message": ":global(...) must not be followed with a type selector",
 		"start": {
 			"line": 17,
diff --git a/packages/svelte/tests/validator/samples/css-mismatched-quotes/errors.json b/packages/svelte/tests/validator/samples/css-mismatched-quotes/errors.json
index 6919f50ce9..cf5ade9b0e 100644
--- a/packages/svelte/tests/validator/samples/css-mismatched-quotes/errors.json
+++ b/packages/svelte/tests/validator/samples/css-mismatched-quotes/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "unexpected-eof",
+		"code": "unexpected_eof",
 		"message": "Unexpected end of input",
 		"start": {
 			"line": 7,
diff --git a/packages/svelte/tests/validator/samples/debug-invalid-args/errors.json b/packages/svelte/tests/validator/samples/debug-invalid-args/errors.json
index b21af2c438..40d459912c 100644
--- a/packages/svelte/tests/validator/samples/debug-invalid-args/errors.json
+++ b/packages/svelte/tests/validator/samples/debug-invalid-args/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "invalid-debug",
+		"code": "invalid_debug",
 		"message": "{@debug ...} arguments must be identifiers, not arbitrary expressions",
 		"start": {
 			"line": 2,
diff --git a/packages/svelte/tests/validator/samples/default-export-anonymous-class/errors.json b/packages/svelte/tests/validator/samples/default-export-anonymous-class/errors.json
index 064c5a4f5a..4615556188 100644
--- a/packages/svelte/tests/validator/samples/default-export-anonymous-class/errors.json
+++ b/packages/svelte/tests/validator/samples/default-export-anonymous-class/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "default-export",
+		"code": "default_export",
 		"message": "A component cannot have a default export",
 		"start": {
 			"line": 2,
diff --git a/packages/svelte/tests/validator/samples/default-export-anonymous-function/errors.json b/packages/svelte/tests/validator/samples/default-export-anonymous-function/errors.json
index 7e20c7c9d4..652aff0e54 100644
--- a/packages/svelte/tests/validator/samples/default-export-anonymous-function/errors.json
+++ b/packages/svelte/tests/validator/samples/default-export-anonymous-function/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "default-export",
+		"code": "default_export",
 		"message": "A component cannot have a default export",
 		"start": {
 			"line": 2,
diff --git a/packages/svelte/tests/validator/samples/default-export/errors.json b/packages/svelte/tests/validator/samples/default-export/errors.json
index 6131408037..5b786d2222 100644
--- a/packages/svelte/tests/validator/samples/default-export/errors.json
+++ b/packages/svelte/tests/validator/samples/default-export/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "default-export",
+		"code": "default_export",
 		"message": "A component cannot have a default export",
 		"start": {
 			"line": 2,
diff --git a/packages/svelte/tests/validator/samples/directive-non-expression/errors.json b/packages/svelte/tests/validator/samples/directive-non-expression/errors.json
index 4d36ab28b3..f7a825454e 100644
--- a/packages/svelte/tests/validator/samples/directive-non-expression/errors.json
+++ b/packages/svelte/tests/validator/samples/directive-non-expression/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "invalid-directive-value",
+		"code": "invalid_directive_value",
 		"message": "Directive value must be a JavaScript expression enclosed in curly braces",
 		"start": {
 			"line": 1,
diff --git a/packages/svelte/tests/validator/samples/dollar-dollar-global-in-markup/errors.json b/packages/svelte/tests/validator/samples/dollar-dollar-global-in-markup/errors.json
index 5624217e87..ec2497f40e 100644
--- a/packages/svelte/tests/validator/samples/dollar-dollar-global-in-markup/errors.json
+++ b/packages/svelte/tests/validator/samples/dollar-dollar-global-in-markup/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "illegal-global",
+		"code": "illegal_global",
 		"message": "$$billsyall is an illegal variable name. To reference a global variable called $$billsyall, use globalThis.$$billsyall",
 		"start": {
 			"line": 1,
diff --git a/packages/svelte/tests/validator/samples/dollar-dollar-global-in-script/errors.json b/packages/svelte/tests/validator/samples/dollar-dollar-global-in-script/errors.json
index fac768b195..85ad4c6df9 100644
--- a/packages/svelte/tests/validator/samples/dollar-dollar-global-in-script/errors.json
+++ b/packages/svelte/tests/validator/samples/dollar-dollar-global-in-script/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "illegal-global",
+		"code": "illegal_global",
 		"message": "$$billsyall is an illegal variable name. To reference a global variable called $$billsyall, use globalThis.$$billsyall",
 		"start": {
 			"line": 2,
diff --git a/packages/svelte/tests/validator/samples/dollar-global-in-markup/errors.json b/packages/svelte/tests/validator/samples/dollar-global-in-markup/errors.json
index 847dacbca8..c7231a3915 100644
--- a/packages/svelte/tests/validator/samples/dollar-global-in-markup/errors.json
+++ b/packages/svelte/tests/validator/samples/dollar-global-in-markup/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "illegal-global",
+		"code": "illegal_global",
 		"message": "$ is an illegal variable name. To reference a global variable called $, use globalThis.$",
 		"start": {
 			"line": 1,
diff --git a/packages/svelte/tests/validator/samples/dollar-global-in-script/errors.json b/packages/svelte/tests/validator/samples/dollar-global-in-script/errors.json
index b924a535d8..e1909896e6 100644
--- a/packages/svelte/tests/validator/samples/dollar-global-in-script/errors.json
+++ b/packages/svelte/tests/validator/samples/dollar-global-in-script/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "illegal-global",
+		"code": "illegal_global",
 		"message": "$ is an illegal variable name. To reference a global variable called $, use globalThis.$",
 		"start": {
 			"line": 2,
diff --git a/packages/svelte/tests/validator/samples/dynamic-element-invalid-tag/errors.json b/packages/svelte/tests/validator/samples/dynamic-element-invalid-tag/errors.json
index 752d26e1b3..ccd34029d2 100644
--- a/packages/svelte/tests/validator/samples/dynamic-element-invalid-tag/errors.json
+++ b/packages/svelte/tests/validator/samples/dynamic-element-invalid-tag/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "invalid-svelte-element-definition",
+		"code": "invalid_svelte_element_definition",
 		"message": "Invalid element definition — must be an {expression}",
 		"start": {
 			"line": 2,
diff --git a/packages/svelte/tests/validator/samples/dynamic-element-missing-tag/errors.json b/packages/svelte/tests/validator/samples/dynamic-element-missing-tag/errors.json
index 58c8af5c66..615138f3b0 100644
--- a/packages/svelte/tests/validator/samples/dynamic-element-missing-tag/errors.json
+++ b/packages/svelte/tests/validator/samples/dynamic-element-missing-tag/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "missing-svelte-element-definition",
+		"code": "missing_svelte_element_definition",
 		"message": "<svelte:element> must have a 'this' attribute",
 		"start": {
 			"line": 2,
diff --git a/packages/svelte/tests/validator/samples/dynamic-element-this/errors.json b/packages/svelte/tests/validator/samples/dynamic-element-this/errors.json
index 4efad529ff..78ee8835be 100644
--- a/packages/svelte/tests/validator/samples/dynamic-element-this/errors.json
+++ b/packages/svelte/tests/validator/samples/dynamic-element-this/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "unexpected-reserved-word",
+		"code": "unexpected_reserved_word",
 		"message": "'this' is a reserved word in JavaScript and cannot be used here",
 		"start": {
 			"line": 2,
diff --git a/packages/svelte/tests/validator/samples/each-block-destructured-object-rest-comma-after/errors.json b/packages/svelte/tests/validator/samples/each-block-destructured-object-rest-comma-after/errors.json
index 13c3d150db..62494b230e 100644
--- a/packages/svelte/tests/validator/samples/each-block-destructured-object-rest-comma-after/errors.json
+++ b/packages/svelte/tests/validator/samples/each-block-destructured-object-rest-comma-after/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "js-parse-error",
+		"code": "js_parse_error",
 		"message": "Comma is not permitted after the rest element",
 		"start": {
 			"line": 5,
diff --git a/packages/svelte/tests/validator/samples/each-block-invalid-context-destructured-object/errors.json b/packages/svelte/tests/validator/samples/each-block-invalid-context-destructured-object/errors.json
index 3cb3bbe0db..7800f62247 100644
--- a/packages/svelte/tests/validator/samples/each-block-invalid-context-destructured-object/errors.json
+++ b/packages/svelte/tests/validator/samples/each-block-invalid-context-destructured-object/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "js-parse-error",
+		"code": "js_parse_error",
 		"message": "Unexpected keyword 'case'",
 		"start": {
 			"line": 1,
diff --git a/packages/svelte/tests/validator/samples/each-block-invalid-context-destructured/errors.json b/packages/svelte/tests/validator/samples/each-block-invalid-context-destructured/errors.json
index 888bc761ac..42c0eb3883 100644
--- a/packages/svelte/tests/validator/samples/each-block-invalid-context-destructured/errors.json
+++ b/packages/svelte/tests/validator/samples/each-block-invalid-context-destructured/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "js-parse-error",
+		"code": "js_parse_error",
 		"message": "Unexpected token",
 		"start": {
 			"line": 1,
diff --git a/packages/svelte/tests/validator/samples/each-block-invalid-context/errors.json b/packages/svelte/tests/validator/samples/each-block-invalid-context/errors.json
index 72c68836a3..7b6d28004b 100644
--- a/packages/svelte/tests/validator/samples/each-block-invalid-context/errors.json
+++ b/packages/svelte/tests/validator/samples/each-block-invalid-context/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "unexpected-reserved-word",
+		"code": "unexpected_reserved_word",
 		"message": "'case' is a reserved word in JavaScript and cannot be used here",
 		"start": {
 			"line": 1,
diff --git a/packages/svelte/tests/validator/samples/event-attribute/errors.json b/packages/svelte/tests/validator/samples/event-attribute/errors.json
index 28a8f9f11a..7204ea671b 100644
--- a/packages/svelte/tests/validator/samples/event-attribute/errors.json
+++ b/packages/svelte/tests/validator/samples/event-attribute/errors.json
@@ -1,7 +1,7 @@
 [
 	{
 		"message": "Event attribute must be a JavaScript expression, not a string",
-		"code": "invalid-event-attribute-value",
+		"code": "invalid_event_attribute_value",
 		"start": {
 			"line": 4,
 			"column": 8
diff --git a/packages/svelte/tests/validator/samples/event-modifiers-invalid-nonpassive/errors.json b/packages/svelte/tests/validator/samples/event-modifiers-invalid-nonpassive/errors.json
index 0230959777..c53951cb67 100644
--- a/packages/svelte/tests/validator/samples/event-modifiers-invalid-nonpassive/errors.json
+++ b/packages/svelte/tests/validator/samples/event-modifiers-invalid-nonpassive/errors.json
@@ -1,7 +1,7 @@
 [
 	{
 		"message": "The 'passive' and 'nonpassive' modifiers cannot be used together",
-		"code": "invalid-event-modifier-combination",
+		"code": "invalid_event_modifier_combination",
 		"start": {
 			"line": 1,
 			"column": 5
diff --git a/packages/svelte/tests/validator/samples/event-modifiers-invalid-passive/errors.json b/packages/svelte/tests/validator/samples/event-modifiers-invalid-passive/errors.json
index db8289791a..d1def4dcb3 100644
--- a/packages/svelte/tests/validator/samples/event-modifiers-invalid-passive/errors.json
+++ b/packages/svelte/tests/validator/samples/event-modifiers-invalid-passive/errors.json
@@ -1,7 +1,7 @@
 [
 	{
 		"message": "The 'passive' and 'preventDefault' modifiers cannot be used together",
-		"code": "invalid-event-modifier-combination",
+		"code": "invalid_event_modifier_combination",
 		"start": {
 			"line": 1,
 			"column": 5
diff --git a/packages/svelte/tests/validator/samples/event-modifiers-invalid/errors.json b/packages/svelte/tests/validator/samples/event-modifiers-invalid/errors.json
index b398cea5e4..178a5b5543 100644
--- a/packages/svelte/tests/validator/samples/event-modifiers-invalid/errors.json
+++ b/packages/svelte/tests/validator/samples/event-modifiers-invalid/errors.json
@@ -1,7 +1,7 @@
 [
 	{
 		"message": "Valid event modifiers are preventDefault, stopPropagation, stopImmediatePropagation, capture, once, passive, nonpassive, self or trusted",
-		"code": "invalid-event-modifier",
+		"code": "invalid_event_modifier",
 		"start": {
 			"line": 1,
 			"column": 8
diff --git a/packages/svelte/tests/validator/samples/html-block-in-attribute/errors.json b/packages/svelte/tests/validator/samples/html-block-in-attribute/errors.json
index 6c7237f030..5eedfb8971 100644
--- a/packages/svelte/tests/validator/samples/html-block-in-attribute/errors.json
+++ b/packages/svelte/tests/validator/samples/html-block-in-attribute/errors.json
@@ -1,8 +1,14 @@
 [
 	{
-		"code": "invalid-tag-placement",
+		"code": "invalid_tag_placement",
 		"message": "{@html ...} tag cannot be in attribute value",
-		"start": { "line": 1, "column": 12 },
-		"end": { "line": 1, "column": 12 }
+		"start": {
+			"line": 1,
+			"column": 12
+		},
+		"end": {
+			"line": 1,
+			"column": 12
+		}
 	}
 ]
diff --git a/packages/svelte/tests/validator/samples/html-block-in-textarea/errors.json b/packages/svelte/tests/validator/samples/html-block-in-textarea/errors.json
index 8d98066d55..c0e5d0e66a 100644
--- a/packages/svelte/tests/validator/samples/html-block-in-textarea/errors.json
+++ b/packages/svelte/tests/validator/samples/html-block-in-textarea/errors.json
@@ -1,8 +1,14 @@
 [
 	{
-		"code": "invalid-tag-placement",
+		"code": "invalid_tag_placement",
 		"message": "{@html ...} tag cannot be inside <textarea>",
-		"start": { "line": 2, "column": 1 },
-		"end": { "line": 2, "column": 1 }
+		"start": {
+			"line": 2,
+			"column": 1
+		},
+		"end": {
+			"line": 2,
+			"column": 1
+		}
 	}
 ]
diff --git a/packages/svelte/tests/validator/samples/illegal-variable-declaration/errors.json b/packages/svelte/tests/validator/samples/illegal-variable-declaration/errors.json
index 788784d1d8..61f0ad0fed 100644
--- a/packages/svelte/tests/validator/samples/illegal-variable-declaration/errors.json
+++ b/packages/svelte/tests/validator/samples/illegal-variable-declaration/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "illegal-variable-declaration",
+		"code": "illegal_variable_declaration",
 		"message": "Cannot declare same variable name which is imported inside <script context=\"module\">",
 		"start": {
 			"line": 12,
diff --git a/packages/svelte/tests/validator/samples/invalid-empty-css-declaration/errors.json b/packages/svelte/tests/validator/samples/invalid-empty-css-declaration/errors.json
index 2ceb3a3694..299cb2fff5 100644
--- a/packages/svelte/tests/validator/samples/invalid-empty-css-declaration/errors.json
+++ b/packages/svelte/tests/validator/samples/invalid-empty-css-declaration/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "invalid-css-declaration",
+		"code": "invalid_css_declaration",
 		"message": "Declaration cannot be empty",
 		"start": {
 			"line": 5,
diff --git a/packages/svelte/tests/validator/samples/invalid-node-placement-2/errors.json b/packages/svelte/tests/validator/samples/invalid-node-placement-2/errors.json
index fdd8af19c2..99fce66db0 100644
--- a/packages/svelte/tests/validator/samples/invalid-node-placement-2/errors.json
+++ b/packages/svelte/tests/validator/samples/invalid-node-placement-2/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "invalid-node-placement",
+		"code": "invalid_node_placement",
 		"message": "<div> is invalid inside <p>",
 		"start": {
 			"line": 4,
diff --git a/packages/svelte/tests/validator/samples/invalid-node-placement/errors.json b/packages/svelte/tests/validator/samples/invalid-node-placement/errors.json
index 259b8f613b..1b43c778ee 100644
--- a/packages/svelte/tests/validator/samples/invalid-node-placement/errors.json
+++ b/packages/svelte/tests/validator/samples/invalid-node-placement/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "invalid-node-placement",
+		"code": "invalid_node_placement",
 		"message": "<a> is invalid inside <a>",
 		"start": {
 			"line": 4,
diff --git a/packages/svelte/tests/validator/samples/let-directive/errors.json b/packages/svelte/tests/validator/samples/let-directive/errors.json
index bb239bafa7..fe5bf7f41a 100644
--- a/packages/svelte/tests/validator/samples/let-directive/errors.json
+++ b/packages/svelte/tests/validator/samples/let-directive/errors.json
@@ -1,8 +1,14 @@
 [
 	{
-		"code": "invalid-let-directive-placement",
+		"code": "invalid_let_directive_placement",
 		"message": "let directive at invalid position",
-		"start": { "line": 6, "column": 15 },
-		"end": { "line": 6, "column": 20 }
+		"start": {
+			"line": 6,
+			"column": 15
+		},
+		"end": {
+			"line": 6,
+			"column": 20
+		}
 	}
 ]
diff --git a/packages/svelte/tests/validator/samples/logic-block-in-attribute/errors.json b/packages/svelte/tests/validator/samples/logic-block-in-attribute/errors.json
index 883fc0e479..c1169837ea 100644
--- a/packages/svelte/tests/validator/samples/logic-block-in-attribute/errors.json
+++ b/packages/svelte/tests/validator/samples/logic-block-in-attribute/errors.json
@@ -1,8 +1,14 @@
 [
 	{
-		"code": "invalid-block-placement",
+		"code": "invalid_block_placement",
 		"message": "{#if ...} block cannot be in attribute value",
-		"start": { "line": 1, "column": 12 },
-		"end": { "line": 1, "column": 12 }
+		"start": {
+			"line": 1,
+			"column": 12
+		},
+		"end": {
+			"line": 1,
+			"column": 12
+		}
 	}
 ]
diff --git a/packages/svelte/tests/validator/samples/logic-block-in-textarea/errors.json b/packages/svelte/tests/validator/samples/logic-block-in-textarea/errors.json
index a371f9b76b..e9f8a9decf 100644
--- a/packages/svelte/tests/validator/samples/logic-block-in-textarea/errors.json
+++ b/packages/svelte/tests/validator/samples/logic-block-in-textarea/errors.json
@@ -1,8 +1,14 @@
 [
 	{
-		"code": "invalid-block-placement",
+		"code": "invalid_block_placement",
 		"message": "{#each ...} block cannot be inside <textarea>",
-		"start": { "line": 2, "column": 1 },
-		"end": { "line": 2, "column": 1 }
+		"start": {
+			"line": 2,
+			"column": 1
+		},
+		"end": {
+			"line": 2,
+			"column": 1
+		}
 	}
 ]
diff --git a/packages/svelte/tests/validator/samples/multiple-script-default-context/errors.json b/packages/svelte/tests/validator/samples/multiple-script-default-context/errors.json
index 58eb092928..6bf421e270 100644
--- a/packages/svelte/tests/validator/samples/multiple-script-default-context/errors.json
+++ b/packages/svelte/tests/validator/samples/multiple-script-default-context/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "duplicate-script-element",
+		"code": "duplicate_script_element",
 		"message": "A component can have a single top-level <script> element and/or a single top-level <script context=\"module\"> element",
 		"start": {
 			"line": 5,
diff --git a/packages/svelte/tests/validator/samples/multiple-script-module-context/errors.json b/packages/svelte/tests/validator/samples/multiple-script-module-context/errors.json
index 58eb092928..6bf421e270 100644
--- a/packages/svelte/tests/validator/samples/multiple-script-module-context/errors.json
+++ b/packages/svelte/tests/validator/samples/multiple-script-module-context/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "duplicate-script-element",
+		"code": "duplicate_script_element",
 		"message": "A component can have a single top-level <script> element and/or a single top-level <script context=\"module\"> element",
 		"start": {
 			"line": 5,
diff --git a/packages/svelte/tests/validator/samples/namespace-invalid/errors.json b/packages/svelte/tests/validator/samples/namespace-invalid/errors.json
index 7081b9da27..df8639c039 100644
--- a/packages/svelte/tests/validator/samples/namespace-invalid/errors.json
+++ b/packages/svelte/tests/validator/samples/namespace-invalid/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "invalid-svelte-option-namespace",
+		"code": "invalid_svelte_option_namespace",
 		"message": "Unsupported <svelte:option> value for \"namespace\". Valid values are \"html\", \"svg\" or \"foreign\".",
 		"start": {
 			"line": 1,
diff --git a/packages/svelte/tests/validator/samples/namespace-non-literal/errors.json b/packages/svelte/tests/validator/samples/namespace-non-literal/errors.json
index 30c7ea279e..36a35167a8 100644
--- a/packages/svelte/tests/validator/samples/namespace-non-literal/errors.json
+++ b/packages/svelte/tests/validator/samples/namespace-non-literal/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "invalid-svelte-option-namespace",
+		"code": "invalid_svelte_option_namespace",
 		"message": "Unsupported <svelte:option> value for \"namespace\". Valid values are \"html\", \"svg\" or \"foreign\".",
 		"start": {
 			"line": 1,
diff --git a/packages/svelte/tests/validator/samples/reactive-declaration-cyclical/errors.json b/packages/svelte/tests/validator/samples/reactive-declaration-cyclical/errors.json
index b4e3161be6..26fbd26534 100644
--- a/packages/svelte/tests/validator/samples/reactive-declaration-cyclical/errors.json
+++ b/packages/svelte/tests/validator/samples/reactive-declaration-cyclical/errors.json
@@ -1,8 +1,14 @@
 [
 	{
 		"message": "Cyclical dependency detected: a → b → a",
-		"code": "cyclical-reactive-declaration",
-		"start": { "line": 5, "column": 1 },
-		"end": { "line": 5, "column": 14 }
+		"code": "cyclical_reactive_declaration",
+		"start": {
+			"line": 5,
+			"column": 1
+		},
+		"end": {
+			"line": 5,
+			"column": 14
+		}
 	}
 ]
diff --git a/packages/svelte/tests/validator/samples/script-invalid-context/errors.json b/packages/svelte/tests/validator/samples/script-invalid-context/errors.json
index d7a502a2f7..173958d6c6 100644
--- a/packages/svelte/tests/validator/samples/script-invalid-context/errors.json
+++ b/packages/svelte/tests/validator/samples/script-invalid-context/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "invalid-script-context",
+		"code": "invalid_script_context",
 		"message": "If the context attribute is supplied, its value must be \"module\"",
 		"start": {
 			"line": 1,
diff --git a/packages/svelte/tests/validator/samples/slot-attribute-invalid/errors.json b/packages/svelte/tests/validator/samples/slot-attribute-invalid/errors.json
index a5a3855787..e421039874 100644
--- a/packages/svelte/tests/validator/samples/slot-attribute-invalid/errors.json
+++ b/packages/svelte/tests/validator/samples/slot-attribute-invalid/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "invalid-slot-placement",
+		"code": "invalid_slot_placement",
 		"message": "Element with a slot='...' attribute must be a child of a component or a descendant of a custom element",
 		"start": {
 			"line": 1,
diff --git a/packages/svelte/tests/validator/samples/style-directive-modifiers-invalid/errors.json b/packages/svelte/tests/validator/samples/style-directive-modifiers-invalid/errors.json
index ba88102f40..3d1373e8cd 100644
--- a/packages/svelte/tests/validator/samples/style-directive-modifiers-invalid/errors.json
+++ b/packages/svelte/tests/validator/samples/style-directive-modifiers-invalid/errors.json
@@ -1,7 +1,7 @@
 [
 	{
 		"message": "Invalid 'style:' modifier. Valid modifiers are: 'important'",
-		"code": "invalid-style-directive-modifier",
+		"code": "invalid_style_directive_modifier",
 		"start": {
 			"line": 1,
 			"column": 8
diff --git a/packages/svelte/tests/validator/samples/svelte-fragment-placement-2/errors.json b/packages/svelte/tests/validator/samples/svelte-fragment-placement-2/errors.json
index 955d756a6d..8415450c90 100644
--- a/packages/svelte/tests/validator/samples/svelte-fragment-placement-2/errors.json
+++ b/packages/svelte/tests/validator/samples/svelte-fragment-placement-2/errors.json
@@ -1,8 +1,14 @@
 [
 	{
-		"code": "invalid-svelte-fragment-placement",
+		"code": "invalid_svelte_fragment_placement",
 		"message": "<svelte:fragment> must be the direct child of a component",
-		"start": { "line": 5, "column": 0 },
-		"end": { "line": 7, "column": 18 }
+		"start": {
+			"line": 5,
+			"column": 0
+		},
+		"end": {
+			"line": 7,
+			"column": 18
+		}
 	}
 ]
diff --git a/packages/svelte/tests/validator/samples/svelte-fragment-placement/errors.json b/packages/svelte/tests/validator/samples/svelte-fragment-placement/errors.json
index 2ad4c8390f..1760c1b8c4 100644
--- a/packages/svelte/tests/validator/samples/svelte-fragment-placement/errors.json
+++ b/packages/svelte/tests/validator/samples/svelte-fragment-placement/errors.json
@@ -1,8 +1,14 @@
 [
 	{
-		"code": "invalid-svelte-fragment-placement",
+		"code": "invalid_svelte_fragment_placement",
 		"message": "<svelte:fragment> must be the direct child of a component",
-		"start": { "line": 7, "column": 2 },
-		"end": { "line": 9, "column": 20 }
+		"start": {
+			"line": 7,
+			"column": 2
+		},
+		"end": {
+			"line": 9,
+			"column": 20
+		}
 	}
 ]
diff --git a/packages/svelte/tests/validator/samples/svelte-head-attributes/errors.json b/packages/svelte/tests/validator/samples/svelte-head-attributes/errors.json
index 026ba121ab..7debd1dfa2 100644
--- a/packages/svelte/tests/validator/samples/svelte-head-attributes/errors.json
+++ b/packages/svelte/tests/validator/samples/svelte-head-attributes/errors.json
@@ -1,8 +1,14 @@
 [
 	{
-		"code": "illegal-svelte-head-attribute",
+		"code": "illegal_svelte_head_attribute",
 		"message": "<svelte:head> cannot have attributes nor directives",
-		"start": { "line": 1, "column": 13 },
-		"end": { "line": 1, "column": 14 }
+		"start": {
+			"line": 1,
+			"column": 13
+		},
+		"end": {
+			"line": 1,
+			"column": 14
+		}
 	}
 ]
diff --git a/packages/svelte/tests/validator/samples/tag-invalid/errors.json b/packages/svelte/tests/validator/samples/tag-invalid/errors.json
index 7fc929b226..506420fbc2 100644
--- a/packages/svelte/tests/validator/samples/tag-invalid/errors.json
+++ b/packages/svelte/tests/validator/samples/tag-invalid/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "invalid-tag-property",
+		"code": "invalid_tag_property",
 		"message": "tag name must be two or more words joined by the \"-\" character",
 		"start": {
 			"line": 1,
diff --git a/packages/svelte/tests/validator/samples/tag-non-string/errors.json b/packages/svelte/tests/validator/samples/tag-non-string/errors.json
index 46c98b70d5..0a41e50b9d 100644
--- a/packages/svelte/tests/validator/samples/tag-non-string/errors.json
+++ b/packages/svelte/tests/validator/samples/tag-non-string/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "invalid-svelte-option-customElement",
+		"code": "invalid_svelte_option_customElement",
 		"message": "\"customElement\" must be a string literal defining a valid custom element name or an object of the form { tag: string; shadow?: \"open\" | \"none\"; props?: { [key: string]: { attribute?: string; reflect?: boolean; type: .. } } }",
 		"start": {
 			"line": 1,
diff --git a/packages/svelte/tests/validator/samples/textarea-value-children/errors.json b/packages/svelte/tests/validator/samples/textarea-value-children/errors.json
index c4aed6b426..955a4180d0 100644
--- a/packages/svelte/tests/validator/samples/textarea-value-children/errors.json
+++ b/packages/svelte/tests/validator/samples/textarea-value-children/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "invalid-textarea-content",
+		"code": "invalid_textarea_content",
 		"message": "A <textarea> can have either a value attribute or (equivalently) child content, but not both",
 		"start": {
 			"line": 1,
diff --git a/packages/svelte/tests/validator/samples/title-no-attributes/errors.json b/packages/svelte/tests/validator/samples/title-no-attributes/errors.json
index 3f0410a6b0..bb2d90a334 100644
--- a/packages/svelte/tests/validator/samples/title-no-attributes/errors.json
+++ b/packages/svelte/tests/validator/samples/title-no-attributes/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "illegal-title-attribute",
+		"code": "illegal_title_attribute",
 		"message": "<title> cannot have attributes nor directives",
 		"start": {
 			"line": 2,
diff --git a/packages/svelte/tests/validator/samples/title-no-children/errors.json b/packages/svelte/tests/validator/samples/title-no-children/errors.json
index 9d7a7667a1..7ecd375438 100644
--- a/packages/svelte/tests/validator/samples/title-no-children/errors.json
+++ b/packages/svelte/tests/validator/samples/title-no-children/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "invalid-title-content",
+		"code": "invalid_title_content",
 		"message": "<title> can only contain text and {tags}",
 		"start": {
 			"line": 2,
diff --git a/packages/svelte/tests/validator/samples/transition-duplicate-in-transition/errors.json b/packages/svelte/tests/validator/samples/transition-duplicate-in-transition/errors.json
index 2af6bfca8b..22029dc956 100644
--- a/packages/svelte/tests/validator/samples/transition-duplicate-in-transition/errors.json
+++ b/packages/svelte/tests/validator/samples/transition-duplicate-in-transition/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "duplicate-transition",
+		"code": "transition_conflict",
 		"message": "An element cannot have both an 'in' directive and a 'transition' directive",
 		"start": {
 			"line": 6,
diff --git a/packages/svelte/tests/validator/samples/transition-duplicate-in/errors.json b/packages/svelte/tests/validator/samples/transition-duplicate-in/errors.json
index eba48be226..e78ad7d93d 100644
--- a/packages/svelte/tests/validator/samples/transition-duplicate-in/errors.json
+++ b/packages/svelte/tests/validator/samples/transition-duplicate-in/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "duplicate-transition",
+		"code": "transition_conflict",
 		"message": "An element can only have one 'in' directive",
 		"start": {
 			"line": 6,
diff --git a/packages/svelte/tests/validator/samples/transition-duplicate-out-transition/errors.json b/packages/svelte/tests/validator/samples/transition-duplicate-out-transition/errors.json
index cb1a474216..6501881182 100644
--- a/packages/svelte/tests/validator/samples/transition-duplicate-out-transition/errors.json
+++ b/packages/svelte/tests/validator/samples/transition-duplicate-out-transition/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "duplicate-transition",
+		"code": "transition_conflict",
 		"message": "An element cannot have both an 'out' directive and a 'transition' directive",
 		"start": {
 			"line": 6,
diff --git a/packages/svelte/tests/validator/samples/transition-duplicate-out/errors.json b/packages/svelte/tests/validator/samples/transition-duplicate-out/errors.json
index 34c57ab1b8..4017396ad2 100644
--- a/packages/svelte/tests/validator/samples/transition-duplicate-out/errors.json
+++ b/packages/svelte/tests/validator/samples/transition-duplicate-out/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "duplicate-transition",
+		"code": "transition_conflict",
 		"message": "An element can only have one 'out' directive",
 		"start": {
 			"line": 6,
diff --git a/packages/svelte/tests/validator/samples/transition-duplicate-transition-in/errors.json b/packages/svelte/tests/validator/samples/transition-duplicate-transition-in/errors.json
index c88dd30d16..ba088b2b21 100644
--- a/packages/svelte/tests/validator/samples/transition-duplicate-transition-in/errors.json
+++ b/packages/svelte/tests/validator/samples/transition-duplicate-transition-in/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "duplicate-transition",
+		"code": "transition_conflict",
 		"message": "An element cannot have both a 'transition' directive and an 'in' directive",
 		"start": {
 			"line": 6,
diff --git a/packages/svelte/tests/validator/samples/transition-duplicate-transition-out/errors.json b/packages/svelte/tests/validator/samples/transition-duplicate-transition-out/errors.json
index 8c1a2a2706..2d62376e2a 100644
--- a/packages/svelte/tests/validator/samples/transition-duplicate-transition-out/errors.json
+++ b/packages/svelte/tests/validator/samples/transition-duplicate-transition-out/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "duplicate-transition",
+		"code": "transition_conflict",
 		"message": "An element cannot have both a 'transition' directive and an 'out' directive",
 		"start": {
 			"line": 6,
diff --git a/packages/svelte/tests/validator/samples/transition-duplicate-transition/errors.json b/packages/svelte/tests/validator/samples/transition-duplicate-transition/errors.json
index 1c93b5cb87..45f6df33f6 100644
--- a/packages/svelte/tests/validator/samples/transition-duplicate-transition/errors.json
+++ b/packages/svelte/tests/validator/samples/transition-duplicate-transition/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "duplicate-transition",
+		"code": "transition_conflict",
 		"message": "An element can only have one 'transition' directive",
 		"start": {
 			"line": 6,
diff --git a/packages/svelte/tests/validator/samples/transition-on-component/errors.json b/packages/svelte/tests/validator/samples/transition-on-component/errors.json
index 7b2403bee6..52155a1480 100644
--- a/packages/svelte/tests/validator/samples/transition-on-component/errors.json
+++ b/packages/svelte/tests/validator/samples/transition-on-component/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "invalid-component-directive",
+		"code": "invalid_component_directive",
 		"message": "This type of directive is not valid on components",
 		"start": {
 			"line": 7,
diff --git a/packages/svelte/tests/validator/samples/window-binding-invalid-innerwidth/errors.json b/packages/svelte/tests/validator/samples/window-binding-invalid-innerwidth/errors.json
index 7f7a7eb6f9..7d5c019464 100644
--- a/packages/svelte/tests/validator/samples/window-binding-invalid-innerwidth/errors.json
+++ b/packages/svelte/tests/validator/samples/window-binding-invalid-innerwidth/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "invalid-binding",
+		"code": "bind_invalid_target",
 		"message": "'innerwidth' is not a valid binding (did you mean 'innerWidth'?)",
 		"start": {
 			"line": 5,
diff --git a/packages/svelte/tests/validator/samples/window-binding-invalid/errors.json b/packages/svelte/tests/validator/samples/window-binding-invalid/errors.json
index dc1fadfc08..52bb5451c0 100644
--- a/packages/svelte/tests/validator/samples/window-binding-invalid/errors.json
+++ b/packages/svelte/tests/validator/samples/window-binding-invalid/errors.json
@@ -1,6 +1,6 @@
 [
 	{
-		"code": "invalid-binding",
+		"code": "bind_invalid_target",
 		"message": "'potato' is not a valid binding",
 		"start": {
 			"line": 5,