---
title: 'Compiler Warnings'
generated: 'generated by process-messages/index.js'
---

## a11y_accesskey

```
Avoid using accesskey
```

## a11y_aria_activedescendant_has_tabindex

```
An element with an aria-activedescendant attribute should have a tabindex value
```

## a11y_aria_attributes

```
`<%name%>` should not have aria-* attributes
```

## a11y_autocomplete_valid

```
'%value%' is an invalid value for 'autocomplete' on `<input type="%type%">`
```

## a11y_autofocus

```
Avoid using autofocus
```

## a11y_click_events_have_key_events

```
Visible, non-interactive elements with a click event must be accompanied by a keyboard event handler. Consider whether an interactive element such as `<button type="button">` or `<a>` might be more appropriate. See https://svelte.dev/docs/accessibility-warnings#a11y-click-events-have-key-events for more details
```

## a11y_consider_explicit_label

```
Buttons and links should either contain text or have an `aria-label` or `aria-labelledby` attribute
```

## a11y_distracting_elements

```
Avoid `<%name%>` elements
```

## a11y_figcaption_index

```
`<figcaption>` must be first or last child of `<figure>`
```

## a11y_figcaption_parent

```
`<figcaption>` must be an immediate child of `<figure>`
```

## a11y_hidden

```
`<%name%>` element should not be hidden
```

## a11y_img_redundant_alt

```
Screenreaders already announce `<img>` elements as an image
```

## a11y_incorrect_aria_attribute_type

```
The value of '%attribute%' must be a %type%
```

## a11y_incorrect_aria_attribute_type_boolean

```
The value of '%attribute%' must be either 'true' or 'false'. It cannot be empty
```

## a11y_incorrect_aria_attribute_type_id

```
The value of '%attribute%' must be a string that represents a DOM element ID
```

## a11y_incorrect_aria_attribute_type_idlist

```
The value of '%attribute%' must be a space-separated list of strings that represent DOM element IDs
```

## a11y_incorrect_aria_attribute_type_integer

```
The value of '%attribute%' must be an integer
```

## a11y_incorrect_aria_attribute_type_token

```
The value of '%attribute%' must be exactly one of %values%
```

## a11y_incorrect_aria_attribute_type_tokenlist

```
The value of '%attribute%' must be a space-separated list of one or more of %values%
```

## a11y_incorrect_aria_attribute_type_tristate

```
The value of '%attribute%' must be exactly one of true, false, or mixed
```

## a11y_interactive_supports_focus

```
Elements with the '%role%' interactive role must have a tabindex value
```

## a11y_invalid_attribute

```
'%href_value%' is not a valid %href_attribute% attribute
```

## a11y_label_has_associated_control

```
A form label must be associated with a control
```

## a11y_media_has_caption

```
`<video>` elements must have a `<track kind="captions">`
```

## a11y_misplaced_role

```
`<%name%>` should not have role attribute
```

## a11y_misplaced_scope

```
The scope attribute should only be used with `<th>` elements
```

## a11y_missing_attribute

```
`<%name%>` element should have %article% %sequence% attribute
```

## a11y_missing_content

```
`<%name%>` element should contain text
```

## a11y_mouse_events_have_key_events

```
'%event%' event must be accompanied by '%accompanied_by%' event
```

## a11y_no_abstract_role

```
Abstract role '%role%' is forbidden
```

## a11y_no_interactive_element_to_noninteractive_role

```
`<%element%>` cannot have role '%role%'
```

## a11y_no_noninteractive_element_interactions

```
Non-interactive element `<%element%>` should not be assigned mouse or keyboard event listeners
```

## a11y_no_noninteractive_element_to_interactive_role

```
Non-interactive element `<%element%>` cannot have interactive role '%role%'
```

## a11y_no_noninteractive_tabindex

```
noninteractive element cannot have nonnegative tabIndex value
```

## a11y_no_redundant_roles

```
Redundant role '%role%'
```

## a11y_no_static_element_interactions

```
`<%element%>` with a %handler% handler must have an ARIA role
```

## a11y_positive_tabindex

```
Avoid tabindex values above zero
```

## a11y_role_has_required_aria_props

```
Elements with the ARIA role "%role%" must have the following attributes defined: %props%
```

## a11y_role_supports_aria_props

```
The attribute '%attribute%' is not supported by the role '%role%'
```

## a11y_role_supports_aria_props_implicit

```
The attribute '%attribute%' is not supported by the role '%role%'. This role is implicit on the element `<%name%>`
```

## a11y_unknown_aria_attribute

```
Unknown aria attribute 'aria-%attribute%'
```
```
Unknown aria attribute 'aria-%attribute%'. Did you mean '%suggestion%'?
```

## a11y_unknown_role

```
Unknown role '%role%'
```
```
Unknown role '%role%'. Did you mean '%suggestion%'?
```

## legacy_code

```
`%code%` is no longer valid — please use `%suggestion%` instead
```

## unknown_code

```
`%code%` is not a recognised code
```
```
`%code%` is not a recognised code (did you mean `%suggestion%`?)
```

## options_deprecated_accessors

```
The `accessors` option has been deprecated. It will have no effect in runes mode
```

## options_deprecated_immutable

```
The `immutable` option has been deprecated. It will have no effect in runes mode
```

## options_missing_custom_element

```
The `customElement` option is used when generating a custom element. Did you forget the `customElement: true` compile option?
```

## options_removed_enable_sourcemap

```
The `enableSourcemap` option has been removed. Source maps are always generated now, and tooling can choose to ignore them
```

## options_removed_hydratable

```
The `hydratable` option has been removed. Svelte components are always hydratable now
```

## options_removed_loop_guard_timeout

```
The `loopGuardTimeout` option has been removed
```

## options_renamed_ssr_dom

```
`generate: "dom"` and `generate: "ssr"` options have been renamed to "client" and "server" respectively
```

## export_let_unused

```
Component has unused export property '%name%'. If it is for external reference only, please consider using `export const %name%`
```

## legacy_component_creation

```
Svelte 5 components are no longer classes. Instantiate them using `mount` or `hydrate` (imported from 'svelte') instead.
```

## non_reactive_update

```
`%name%` is updated, but is not declared with `$state(...)`. Changing its value will not correctly trigger updates
```

## perf_avoid_inline_class

```
Avoid 'new class' — instead, declare the class at the top level scope
```

## perf_avoid_nested_class

```
Avoid declaring classes below the top level scope
```

## reactive_declaration_invalid_placement

```
Reactive declarations only exist at the top level of the instance script
```

## reactive_declaration_module_script_dependency

```
Reassignments of module-level declarations will not cause reactive statements to update
```

## reactive_declaration_non_reactive_property

```
Properties of objects and arrays are not reactive unless in runes mode. Changes to this property will not cause the reactive statement to update
```

## state_referenced_locally

```
State referenced in its own scope will never update. Did you mean to reference it inside a closure?
```

## store_rune_conflict

```
It looks like you're using the `$%name%` rune, but there is a local binding called `%name%`. Referencing a local variable with a `$` prefix will create a store subscription. Please rename `%name%` to avoid the ambiguity
```

## css_unused_selector

```
Unused CSS selector "%name%"
```

## attribute_avoid_is

```
The "is" attribute is not supported cross-browser and should be avoided
```

## attribute_global_event_reference

```
You are referencing `globalThis.%name%`. Did you forget to declare a variable with that name?
```

## attribute_illegal_colon

```
Attributes should not contain ':' characters to prevent ambiguity with Svelte directives
```

## attribute_invalid_property_name

```
'%wrong%' is not a valid HTML attribute. Did you mean '%right%'?
```

## attribute_quoted

```
Quoted attributes on components and custom elements will be stringified in a future version of Svelte. If this isn't what you want, remove the quotes
```

## bind_invalid_each_rest

```
The rest operator (...) will create a new object and binding '%name%' with the original object will not work
```

## block_empty

```
Empty block
```

## component_name_lowercase

```
`<%name%>` will be treated as an HTML element unless it begins with a capital letter
```

## element_invalid_self_closing_tag

```
Self-closing HTML tags for non-void elements are ambiguous — use `<%name% ...></%name%>` rather than `<%name% ... />`
```

## event_directive_deprecated

```
Using `on:%name%` to listen to the %name% event is deprecated. Use the event attribute `on%name%` instead
```

## node_invalid_placement_ssr

```
%thing% is invalid inside `<%parent%>`. When rendering this component on the server, the resulting HTML will be modified by the browser, likely resulting in a `hydration_mismatch` warning
```

This code will work when the component is rendered on the client (which is why this is a warning rather than an error), but if you use server rendering it will cause hydration to fail.
- `<p>hello <div>world</div></p>` will result in `<p>hello </p><div>world</div><p></p>` for example (the `<div>` autoclosed the `<p>` because `<p>` cannot contain block-level elements)
- `<option><div>option a</div></option>` will result in `<option>option a</option>` (the `<div>` is removed)
- `<table><tr><td>cell</td></tr></table>` will result in `<table><tbody><tr><td>cell</td></tr></tbody></table>` (a `<tbody>` is auto-inserted)
HTML restricts where certain elements can appear. In case of a violation the browser will 'repair' the HTML in a way that breaks Svelte's assumptions about the structure of your components. Some examples:


## script_context_deprecated

```
`context="module"` is deprecated, use the `module` attribute instead
```

## script_unknown_attribute

```
Unrecognized attribute — should be one of `generics`, `lang` or `module`. If this exists for a preprocessor, ensure that the preprocessor removes it
```

## slot_element_deprecated

```
Using `<slot>` to render parent content is deprecated. Use `{@render ...}` tags instead
```

## svelte_component_deprecated

```
`<svelte:component>` is deprecated in runes mode — components are dynamic by default
```

```diff
<script>
	...
	let condition = $state(false);
+	const Component = $derived(condition ? Y : Z);
</script>
- <svelte:component this={condition ? Y : Z} />
+ <Component />
```
A derived value may be used in other contexts:
```diff
{#each items as item}
-	<svelte:component this={item.condition ? Y : Z} />
+	{@const Component = item.condition ? Y : Z}
+	<Component />
{/each}
```
For complex component resolution logic, an intermediary, capitalized variable may be necessary. E.g. in places where `@const` can be used:
In some cases `<object.property>` syntax can be used as a replacement; a lowercased variable with property access is recognized as a component in Svelte 5.
In Svelte 5 this is no longer true — if `X` changes, `<X>` re-renders.
In previous versions of Svelte, the component constructor was fixed when the component was rendered. In other words, if you wanted `<X>` to re-render when `X` changed, you would either have to use `<svelte:component this={X}>` or put the component inside a `{#key X}...{/key}` block.


## svelte_element_invalid_this

```
`this` should be an `{expression}`. Using a string attribute value will cause an error in future versions of Svelte
```

## svelte_self_deprecated

```
`<svelte:self>` is deprecated — use self-imports (e.g. `import %name% from './%basename%'`) instead
```