x/tools/gopls: Completion: nil deref in expectedCompositeLiteralType

[adonovan]

#!stacks
"sigpanic" && "completion.expectedCompositeLiteralType:+1"

Issue created by stacks.

func expectedCompositeLiteralType(clInfo *compLitInfo, pos token.Pos) types.Type {
	switch t := clInfo.clType.(type) {
	case *types.Slice:
		if clInfo.inKey {
			return types.Typ[types.UntypedInt]
		}
		return t.Elem()

This stack v8QlHQ was reported by telemetry:

• crash/crash
• runtime.gopanic:+69
• runtime.panicmem:=262
• runtime.sigpanic:+19
• golang.org/x/tools/gopls/internal/golang/completion.expectedCompositeLiteralType:+1
• golang.org/x/tools/gopls/internal/golang/completion.inferExpectedResultTypes:+20
• golang.org/x/tools/gopls/internal/golang/completion.(*completer).inferExpectedTypeArg:+15
• golang.org/x/tools/gopls/internal/golang/completion.expectedCandidate:+163
• golang.org/x/tools/gopls/internal/golang/completion.Completion:+161
• 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/gopls@v0.18.1 go1.23.6 darwin/arm64 neovim,vscode (2)

Dups: 7NJTCg

[adonovan]

This one is trivial.

[gabyhelp]

Related Issues

• x/tools/gopls: nil Signature (?) deref in Completion #70634 (closed)
• x/tools/gopls: completion: failed type assertion in inferExpectedTypeArg #70889 (closed)
• x/tools/gopls: Completion: failed type assertion in completer.item #71044 (closed)
• x/tools/gopls: failed *types.Func type assertion in populateCommentCompletions #71273 (closed)
• x/tools/gopls: OOB index crash in completion.expectedReturnStmtType #70636 (closed)
• x/tools/gopls: Completion: "ZeroString for unexpected type" panic #70744 (closed)
• x/tools/gopls: Hover: nil deref in parseDocLink #70635 (closed)
• x/tools/gopls: stubmethods: nil deref of FuncType.Results in fromReturnStmt #70967 (closed)
• x/tools/gopls: Hover: invalid nil entry in types.Defs map #69362 (closed)
• x/tools/gopls: Hover: nil deref in golang.StdSymbolOf #70969 (closed)

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

[gopherbot]

Change https://go.dev/cl/659375 mentions this issue: gopls/internal/golang/completion: ensure expectedCompositeLiteralType arg is not nil

[adonovan]

This stack 7NJTCg was reported by telemetry:

• crash/crash
• runtime.gopanic:+69
• runtime.panicmem:=262
• runtime.sigpanic:+19
• golang.org/x/tools/gopls/internal/golang/completion.expectedCompositeLiteralType:+1
• golang.org/x/tools/gopls/internal/golang/completion.inferExpectedResultTypes:+20
• golang.org/x/tools/gopls/internal/golang/completion.expectedCandidate:+63
• golang.org/x/tools/gopls/internal/golang/completion.Completion:+161
• 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/gopls@v0.18.1 go1.23.7 linux/amd64 other (4)