x/tools/gopls: completion: failed type assertion in inferExpectedTypeArg

[adonovan]

#!stacks
"panicdottypeI" && "inferExpectedTypeArg:+11"

Issue created by stacks.

	// Infer the type parameters in a function call based on it's context
	sig := c.pkg.TypesInfo().Types[callNode.Fun].Type.(*types.Signature) // <--- panic here
	expectedResults := inferExpectedResultTypes(c, callNodeIdx)
	if typeParamIdx < 0 || typeParamIdx >= sig.TypeParams().Len() {
		return nil
	}

This stack w_8rjA was reported by telemetry:

• crash/crash
• runtime.gopanic:+69
• runtime.panicdottypeE:=275
• runtime.panicdottypeI:+5
• golang.org/x/tools/gopls/internal/golang/completion.(*completer).inferExpectedTypeArg:+11
• golang.org/x/tools/gopls/internal/golang/completion.expectedCandidate:+148
• golang.org/x/tools/gopls/internal/golang/completion.Completion:+150
• golang.org/x/tools/gopls/internal/server.(*server).Completion:+19
• golang.org/x/tools/gopls/internal/protocol.serverDispatch:+193
• golang.org/x/tools/gopls/internal/lsprpc.(*streamServer).ServeStream.ServerHandler.func3:+5
• golang.org/x/tools/gopls/internal/lsprpc.(*streamServer).ServeStream.handshaker.func4:+52
• golang.org/x/tools/gopls/internal/protocol.Handlers.MustReplyHandler.func1:+2
• golang.org/x/tools/gopls/internal/protocol.Handlers.AsyncHandler.func2.2:+3
• runtime.goexit:+0

golang.org/x/tools/[email protected] go1.23.4 darwin/amd64 vscode (1)

Dups: brclNw

[gabyhelp]

Related Issues

• x/tools/gopls: OOB index crash in completion.expectedReturnStmtType #70636 (closed)
• x/tools/gopls: nil Signature (?) deref in Completion #70634 (closed)
• x/tools/gopls: Completion: "ZeroString for unexpected type" panic #70744 (closed)
• x/tools/gopls: bug report in GetIfaceStubInfo #70666
• x/tools/gopls: panic in completion.enclosingFunction #49397 (closed)
• x/tools/gopls: crash in Hover (telemetry) #69362
• x/tools/gopls: automated issue report (crash) - unhandled basic type #40956 (closed)
• x/tools/gopls: Hover: nil deref in parseDocLink #70635 (closed)
• x/tools/gopls: panic in completion on variables of type *error #56505 (closed)
• x/tools/gopls: analysisinternal.ZeroValue crash on (presumably) unsafe.Pointer #70585 (closed)

_{(Emoji vote if this was helpful or unhelpful; more detailed feedback welcome in this discussion.)}

[findleyr]

Hmm, we may want to consider this for a v0.17.1.

[gopherbot]

Change https://go.dev/cl/637635 mentions this issue: gopls/internal/golang/completion: fix crash in instance conversion

[gopherbot]

Change https://go.dev/cl/637675 mentions this issue: [gopls-release-branch.0.17] gopls/internal/golang/completion: fix crash in instance conversion

[adonovan]

This stack brclNw was reported by telemetry:

• crash/crash
• runtime.gopanic:+69
• runtime.panicdottypeE:=275
• runtime.panicdottypeI:+5
• golang.org/x/tools/gopls/internal/golang/completion.(*completer).inferExpectedTypeArg:+11
• golang.org/x/tools/gopls/internal/golang/completion.expectedCandidate:+163
• golang.org/x/tools/gopls/internal/golang/completion.Completion:+150
• golang.org/x/tools/gopls/internal/server.(*server).Completion:+19
• golang.org/x/tools/gopls/internal/protocol.serverDispatch:+193
• golang.org/x/tools/gopls/internal/lsprpc.(*streamServer).ServeStream.ServerHandler.func3:+5
• golang.org/x/tools/gopls/internal/lsprpc.(*streamServer).ServeStream.handshaker.func4:+52
• golang.org/x/tools/gopls/internal/protocol.Handlers.MustReplyHandler.func1:+2
• golang.org/x/tools/gopls/internal/protocol.Handlers.AsyncHandler.func2.2:+3
• runtime.goexit:+0

golang.org/x/tools/[email protected] go1.23.4 linux/amd64 vscode (1)