Add elaboration when call fails all overloads but succeeds against the implementation signature #41001
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…e implementation signature
typescript-bot
added
Author: Team
For Milestone Bug
| @@ -274,7 +274,7 @@ namespace ts { | |||
| result.relatedInformation = relatedInformation ? | |||
| relatedInformation.length ? | |||
| relatedInformation.map(r => convertToDiagnosticRelatedInformation(r, newProgram, toPath)) : | |||
| emptyArray : | |||
| [] : | |||
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did we ever figure out what the performance impact of [] vs emptyArray is? Last I heard is that [] is better?
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...eh? In this case, it's just because we mutate relatedInformation in some places, so using a global singleton is bad.
| const candidate = getSignatureFromDeclaration(implDecl as FunctionLikeDeclaration); | ||
| const isSingleNonGenericCandidate = !candidate.typeParameters; | ||
| if (!!chooseOverload([candidate], assignableRelation, isSingleNonGenericCandidate)) { | ||
| addRelatedInfo(d, createDiagnosticForNode(implDecl, Diagnostics.The_call_would_have_succeeded_against_this_implementation_but_implementation_signatures_of_overloads_are_not_externally_visible)); |
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does this mutate the related list? (and is that why you clone into related above?)
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addRelatedInfo, as the name implies, has always appended to the existing list.
Pretty often - almost any overload error where the overload being compiled against is actually in your source code (and thus has a body) rather than a library. |
Yeah, people on the VS Code team hit this, and it's a beginner mistake. If you don't hear about it much, it's because you bang your head on it for a bit and then figure it out. |
| !!! error TS2769: Argument of type 'boolean' is not assignable to parameter of type 'number'. | ||
| !!! related TS2793 tests/cases/compiler/functionOverloads2.ts:3:10: The call would have succeeded against this implementation, but implementation signatures of overloads are not externally visible. |
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Causes crashes in Definitely Typed -- see types/agent-base for example. I'll file a bug. |
Fixes #4797