pluralia

#### What it does Closes #11273. Centers spinning icons for the tree-view. #### How to test 1. Install [the test extension](https://github.com/eclipse-theia/theia/files/9292635/custom-view-samples-0.0.1.vsix.zip) ([sources](https://github.com/pluralia/vscode-extension-samples/tree/spin-icon-test/tree-view-sample)) 2. Open the _File Explorer_ tab -> Icons...

Add the ability to use parentheses when declaring `TypeAlternatives`

6

The Langium grammar allows to create the rule `X`, where the property `x` is an array of type alternatives, and it has to be possible to declare the corresponding type...

Cyclic inheritance of types

2

Some grammars produce cyclic inherited types. For example, these 2 grammars ``` A infers TypeA: B ({infer TypeC.left=current} name=ID)*; B infers TypeB: '(' A ')' | {infer TypeD} value=NUMBER; ```...

Add type consistency validation for actions

2

It's necessary to add validation for actions that use declared types. For example, interface `X` has a property `name`, but type `X` from action has a property `count` -- validation...

Various code actions about types

3

Write some code actions as quick fixes for validations from #426: - [ ] type names duplication -> removes a duplicated type - [x] validation of property name duplication (#430)...

Incorrect properties lifting to the parent node

5

Rules `AssignmentExpression`, `OrExpression` and `AndExpression` have a common property `operator` and inherit `BinaryExpression`, so the `BinaryExpression` in the generated AST interface has to contain a property `operator: 'Or' | 'And'...

Support for properties in the parent type

8

Unassigned rule calls create a parent-child relation, and in the example below, `AbstractToken` is a parent of `TokenA`, `TokenB` and `TokenC`. `AbstractToken` also has own property cardinality. ``` AbstractToken: (...

Improve container types calculation

2

An `AstNode` instance has an optional field `$container`, which presents its container -- a parental `AstNode`. The feature makes casting an `AstNode` to its container pretty comfortable, however it works...

A multi-mode lexer example

1

A multi-mode lexer example should be created to demonstrate abilities, added in [#398](https://github.com/langium/langium/pull/398).

The strict mode for types inference

2

In Langium 0.2.0 types are inferred from rules names implicitly. For example, the following 2 examples will infer a type `MyRule` with the attribute `name`. ``` MyRule: name=ID; ``` ```...