break out locator stuff from the rest of global state

packages/svelte/src/compiler/index.js

@@ -96,6 +96,7 @@ export function compileModule(source, options) {
  * @returns {Record<string, any>}
  */
 
+// TODO 6.0 remove unused `filename`
 /**
  * The parse function parses a component, returning only its abstract syntax tree.
  *
@@ -104,14 +105,15 @@ export function compileModule(source, options) {
  *
  * The `loose` option, available since 5.13.0, tries to always return an AST even if the input will not successfully compile.
  *
+ * The `filename` option is unused and will be removed in Svelte 6.0.
+ *
  * @param {string} source
  * @param {{ filename?: string; rootDir?: string; modern?: boolean; loose?: boolean }} [options]
  * @returns {AST.Root | LegacyRoot}
  */
-export function parse(source, { filename, rootDir, modern, loose } = {}) {
+export function parse(source, { modern, loose } = {}) {
 	source = remove_bom(source);
 	state.reset_warning_filter(() => false);
-	state.reset(source, { filename: filename ?? '(unknown)', rootDir });
 
 	const ast = _parse(source, loose);
 	return to_public_ast(source, ast, modern);

packages/svelte/src/compiler/phases/1-parse/index.js

@@ -9,6 +9,7 @@ import { create_fragment } from './utils/create.js';
 import read_options from './read/options.js';
 import { is_reserved } from '../../../utils.js';
 import { disallow_children } from '../2-analyze/visitors/shared/special-element.js';
+import * as state from '../../state.js';
 
 const regex_position_indicator = / \(\d+:\d+\)$/;
 
@@ -301,6 +302,8 @@ export class Parser {
  * @returns {AST.Root}
  */
 export function parse(template, loose = false) {
+	state.set_source(template);
+
 	const parser = new Parser(template, loose);
 	return parser.root;
 }

packages/svelte/src/compiler/state.js

@@ -30,6 +30,12 @@ export let dev;
 
 export let locator = getLocator('', { offsetLine: 1 });
 
+/** @param {string} value */
+export function set_source(value) {
+	source = value;
+	locator = getLocator(source, { offsetLine: 1 });
+}
+
 /**
  * @param {AST.SvelteNode & { start?: number | undefined }} node
  */
@@ -100,7 +106,7 @@ export function reset(_source, options) {
 		filename = filename.replace(root_dir, '').replace(/^[/\\]/, '');
 	}
 
-	locator = getLocator(source, { offsetLine: 1 });
+	set_source(source);
 	warnings = [];
 	ignore_stack = [];
 	ignore_map.clear();