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API: Exception in TypeChecker.typeToTypeNode #45515
Description
Bug Report
🔎 Search Terms
typeToTypeNode kind undefined
🕗 Version & Regression Information
4.3.2 and earlier versions (not sure when it started)
- This is a crash
⏯ Playground Link
💻 Code
Using compiler API:
function transformVariableDeclaration(statement: ts.VariableDeclaration, checker: ts.TypeChecker) {
if (statement.initializer) {
const initializerType = checker.getTypeAtLocation(statement.initializer);
const initializerTypeNode = checker.typeToTypeNode(initializerType, undefined, undefined); // TypeError: Cannot read property 'kind' of undefined
// ...
}
}Target code being transpiled:
type Foo = (fn: (...args: [][]) => void) => void;
const foo: Foo = (bar => {});Exception thrown:
Exception has occurred: TypeError: Cannot read property 'kind' of undefined
at Object.parenthesizeElementTypeOfArrayType (node_modules\typescript\lib\typescript.js:20825:28)
at Object.createArrayTypeNode (node_modules\typescript\lib\typescript.js:22343:53)
at typeReferenceToTypeNode (node_modules\typescript\lib\typescript.js:49344:52)
at typeToTypeNodeHelper (node_modules\typescript\lib\typescript.js:49085:95)
at serializeTypeForDeclaration (node_modules\typescript\lib\typescript.js:50323:30)
at symbolToParameterDeclaration (node_modules\typescript\lib\typescript.js:49803:41)
at node_modules\typescript\lib\typescript.js:49725:263
at Array.map (<anonymous>)
at signatureToSignatureDeclarationHelper (node_modules\typescript\lib\typescript.js:49725:229)
at createTypeNodeFromObjectType (node_modules\typescript\lib\typescript.js:49296:49)
🙁 Actual behavior
When calling typeToTypeNode an exception is thrown.
🙂 Expected behavior
No exception should be thrown and undefined should be returned.
Tracing through the ts code, undefined is returned from typeReferenceToTypeNode here (linking to online editor since github can't display the file) and there is a comment referencing this issue. That is assigned to the object attempting to be accessed.
The trigger seems to be the rest parameter type being an array of empty tuples. The real code that triggered the issue used some tricky generics to arrive at that type, but this direct version was able to reproduce the same issue.
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