build(deps): bump langium from 3.5.0 to 4.0.0

[dependabot]

Bumps langium from 3.5.0 to 4.0.0.

Release notes

Sourced from langium's releases.

v4.0.0

Changes: https://github.com/eclipse-langium/langium/blob/main/packages/langium/CHANGELOG.md#v400-jul-2025

Changelog

Sourced from langium's changelog.

v4.0.0 (Jul. 2025)

Multi-Target References

With the new multi-target references (#1509), references in your language can now target multiple elements at once:

interface Obj {
    A: number
}
interface Obj {
    B: string
}
// `Obj` is a reference to both interfaces (not only one of them)
// Our type system should merge those definitions
const x: Obj = {
    A: 123,
    B: "hello world"
}

There are a lot of existing programming languages out there that provide features like interface merging or partial classes, which allow you to target multiple AST elements with one reference. This feature is now available in the grammar language via the [+ReferenceType] syntax:

Item: name=ID;
ReferenceElement: item=[+Item]; // Can reference multiple `Item` elements with the same name

This will generate a item: MultiReference<Item> field now.

Infix Operator Rules

To improve readability of grammars, adopters can now use the new infix rule notation (#1836) to declare parsing rules used for infix operator parsing:

infix BinaryExpression on PrimaryExpression:
    '%' // <-- Highest precedence
    > '^'
    > '*' | '/'
    > '+' | '-';  // <-- Lowest precedence
PrimaryExpression infers Expression:
'(' Expression ')' |
{infer NumberLiteral} value=NUMBER;

Note that the previous tree-rewriting action based grammar is still (and always will be) supported. In addition to better readability, the new notation also makes use of performance optimizations to speed up expression parsing by roughly 50% compared to the typical way of writing expressions.

... (truncated)

Commits

• 5ce8d6b Update versions and changelog for version 4.0 of Langium (#1988)
• 4136f7d Remove long-time deprecated properties (#1991)
• 9f4729b AstUtils: added an optional trace map to copyAstNode (#1990)
• 47d629c Improve generated ast.ts regarding multiple languages (#1979)
• ee5f71d Disable syntax highlighting delta (#1985)
• 7c4f871 Enable explicit types for infix rules (#1954)
• 6d9a47e Added DocumentBuilder method to reset document state
• 56edb45 Make linker subclassing easier (#1981)
• 28bc964 langium/generate: supplement of the generator API (#1965)
• 8ee6977 feat: pass ref info and context to createReferenceCompletionItem (#1976)
• Additional commits viewable in compare view

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[dependabot]

Superseded by #1397.