allow this in typeQuery
#43898
allow this in typeQuery
#43898
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tests/baselines/reference/initializerReferencingConstructorParameters.errors.txt
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| var str: typeof this.this = ''; | ||
| } | ||
| } |
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please add tests of
- implicitly any usage, like
function f() { let x: typeof this.no = 1 }. (x should have typeany) - implicit any errors for the same code, but when noImplicitThis: true
- The same usage in
function f (this: { no: number }) - usage inside arrow functions, to make sure that the emit is correct. It would be good to have an arrow function inside a container that binds this, like a class, and in one that doesn't, like a module.
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Ooops, this type can not be used in plain functions. 🤷
function Test1() {
let x: typeof this.no = 1
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!!! error TS2526: A 'this' type is available only in a non-static member of a class or interface.
}
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That error is wrong, then, because this.no is an expression, not a type. The type would be like let x: this['no'].
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I did not notice the differences between this type and this expression. Changing getThisType to checkThisExpression fixed it.
src/compiler/checker.ts
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| @@ -27253,7 +27257,8 @@ namespace ts { | |||
| } | |||
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| function checkQualifiedName(node: QualifiedName, checkMode: CheckMode | undefined) { | |||
| return checkPropertyAccessExpressionOrQualifiedName(node, node.left, checkNonNullExpression(node.left), node.right, checkMode); | |||
| const leftType = isTypeQueryNode(node.parent) && isThisIdentifier(node.left) ? checkNonNullType(checkThisExpression(node.left), node.left) : checkNonNullExpression(node.left); | |||
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does this work when the QualifiedName is nested, like this.x.y? I think you need a test for this.
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It doesn't work for this.x.y. I've replaced isTypeQueryNode with isPartOfTypeQuery
src/compiler/utilities.ts
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| export function isThisInTypeQuery(node: Node): boolean { | ||
| return isThisIdentifier(node) && | ||
| (node.parent.kind === SyntaxKind.TypeQuery || | ||
| (node.parent.kind === SyntaxKind.QualifiedName && (node.parent as QualifiedName).left === node)); |
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the QualifiedName case doesn't check that its ultimate parent is a TypeQuery, so I think you could maybe fool this with this.x in a weird location, or o.this.x The latter should be easy to add a test for; I don't know what test you need for the former.
Fixes #1554