x/tools/gopls: failed *types.Func type assertion in populateCommentCompletions

[adonovan]

#!stacks
"panicdottypeI" && "populateCommentCompletions:+84" ||
// post CL 642877:
"bug.Reportf" && "populateCommentCompletions.func1:=1086" && "populateCommentCompletions:+98"

Issue created by stacks.

		case *ast.FuncDecl:
			c.addFieldItems(node.Recv)
			c.addFieldItems(node.Type.Params)
			c.addFieldItems(node.Type.Results)

			// collect receiver struct fields
			if node.Recv != nil {
				sig := c.pkg.TypesInfo().Defs[node.Name].(*types.Func).Signature() // <-- type assert failed

Very similar to #70889.

This stack QTs-mg was reported by telemetry:

• crash/crash
• runtime.gopanic:+69
• runtime.panicdottypeE:=275
• runtime.panicdottypeI:+5
• golang.org/x/tools/gopls/internal/golang/completion.(*completer).populateCommentCompletions:+84
• golang.org/x/tools/gopls/internal/golang/completion.(*completer).collectCompletions:+12
• golang.org/x/tools/gopls/internal/golang/completion.Completion:+152
• 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@v0.17.1 go1.23.3 darwin/arm64 neovim (1)

Dups: LQqDuQ

[gabyhelp]

Related Issues

• x/tools/gopls: completion: failed type assertion in inferExpectedTypeArg #70889 (closed)
• x/tools/gopls: Completion: failed type assertion in completer.item #71044
• 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: stubmethods: nil deref of FuncType.Results in fromReturnStmt #70967 (closed)
• x/tools/gopls: crash in Hover (telemetry) #69362
• x/tools/gopls: Hover: nil deref in parseDocLink #70635 (closed)
• x/tools/gopls: Rename: crash due to Info.Defs[id]=nil bug in checkStructField #70968
• x/tools/gopls: CodeAction: nil panic in findMatchingDiagnostics #71028 (closed)

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

[gopherbot]

Change https://go.dev/cl/642877 mentions this issue: gopls/internal/golang/completion: debugging missing func def