go/types: SEGV in Named.stateHas

[adonovan]

#!stacks
"sigpanic" && "(*Named).stateHas"

Issue created by stacks.

This stack cIc0EA was reported by telemetry:

• crash/crash
• runtime.gopanic:+70,+0x15b
• go/types.(*Checker).handleBailout:+25,+0x93
• go/types.(*Checker).Files.deferwrap1:+0,+0x1f
• runtime.gopanic:+51,+0x12b
• runtime.panicmem:=336,+0x2ef
• runtime.sigpanic:+19,+0x2c0
• go/types.(*Named).stateHas:=292,+0x28
• go/types.(*Named).unpack:+1,+0x38
• go/types.(*Named).Underlying:+1,+0x1f
• go/types.(*Alias).Underlying:+0,+0x3b
• go/types.lookupFieldOrMethodImpl:+14,+0x93
• go/types.lookupFieldOrMethod:+18,+0xe3
• go/types.(*Checker).selector:+135,+0x403
• go/types.(*Checker).exprInternal:+43,+0x283
• go/types.(*Checker).rawExpr:+10,+0x113
• go/types.(*Checker).exprOrType:+1,+0x47
• go/types.(*Checker).callExpr:+14,+0x293
• go/types.(*Checker).exprInternal:+92,+0x6d7

golang.org/x/tools/gopls@v0.22.0 go1.26.2 darwin/arm64 gopls.client=other,vscode (1)

Use this command to reproduce the executable:
(HOME=$(mktemp -d); GOOS=darwin GOARCH=arm64 GOTOOLCHAIN=go1.26.2 go install golang.org/x/tools/gopls@v0.22.0 && find $HOME/go/bin -type f)
To disassemble: go tool objdump exe | less

[gabyhelp]

Related Issues

• go/types: SEGV in (*Named).TypeArgs due to invalid receiver #80275
• go/types: SEGV in typeWriter.typ #80276
• x/tools/gopls: types.isString crashes in MOV reg,reg instruction #77920 (closed)
• go/types: SEGV in tpWalker.isParameterized, case Signature #79772
• x/tools/gopls: SEGV in (*types.*Checker).Ident due to nil or invalid *ast.Ident in syntax tree #77078 (closed)
• x/tools/gopls: SEGV loading m.used field from non-nil map pointer (in types.Scope.elems map) #76979 (closed)
• go/types: alias TypeName has nil typ #77321
• x/tools/gopls: impossible panic reading rtype.hash in type assertion #76328 (closed)
• x/tools/gopls: SEGV in go/types due to invalid pointer in BinaryExpr.Y #76238 (closed)
• x/tools/gopls: SEGV while preprinting TypeAssertionError in panicdottypeE #79918 (closed)

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