svelte/packages/svelte/messages/compile-errors/runes.md

## invalid_legacy_props

> Cannot use `$$props` in runes mode

## invalid_legacy_rest_props

> Cannot use `$$restProps` in runes mode

## invalid_legacy_reactive_statement

> `$:` is not allowed in runes mode, use `$derived` or `$effect` instead

## invalid_legacy_export

> Cannot use `export let` in runes mode — use $props instead

## invalid_rune_usage

> Cannot use %rune% rune in non-runes mode

## invalid_state_export

> 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

## invalid_derived_export

> Cannot export derived state from a module. To expose the current derived value, export a function returning its value

## invalid_props_id

> `$props()` can only be used with an object destructuring pattern

## invalid_props_pattern

> `$props()` assignment must not contain nested properties or computed keys

## invalid_props_location

> `$props()` can only be used at the top level of components as a variable declaration initializer

## invalid_bindable_location

> `$bindable()` can only be used inside a `$props()` declaration

## invalid_state_location

> `%rune%(...)` can only be used as a variable declaration initializer or a class field

## invalid_effect_location

> `$effect()` can only be used as an expression statement

## invalid_host_location

> `$host()` can only be used inside custom element component instances

## invalid_assignment

> Cannot assign to %thing%

## invalid_binding

> Cannot bind to %thing%

## invalid_rune_args

> `%rune%` cannot be called with arguments

## invalid_rune_args_length

> `%rune%` must be called with %args%

## invalid_runes_mode_import

> %name% cannot be used in runes mode

## duplicate_props_rune

> Cannot use `$props()` more than once

## invalid_each_assignment

> 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`)

## invalid_snippet_assignment

> Cannot reassign or bind to snippet parameter

## invalid_derived_call

> `$derived.call(...)` has been replaced with `$derived.by(...)`

## conflicting_property_name

> Cannot have a property and a component export with the same name