x/tools/internal/analysisinternal: panic in IsTypeNamed

[adonovan]

Observed in https://ci.chromium.org/ui/p/golang/builders/ci/x_tools-gotip-darwin-amd64-longtest/b8726292744544624369/overview:

func IsTypeNamed(t types.Type, pkgPath string, names ...string) bool {
	if named, ok := types.Unalias(t).(*types.Named); ok {
		tname := named.Obj() <--- SIGSEGV
		return tname != nil &&
			isPackageLevel(tname) &&
			tname.Pkg().Path() == pkgPath &&
			slices.Contains(names, tname.Name())
	}
	return false
}

Looks like a nil *types.Named found its way into a types.Object.

panic: runtime error: invalid memory address or nil pointer dereference [recovered]
	panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x20 pc=0xe923009]

goroutine 86548 [running]:
golang.org/x/tools/gopls/internal/cache.(*action).exec.func7.1()
	/Users/swarming/.swarming/w/ir/x/w/targetrepo564898521/gopls/internal/cache/analysis.go:1196 +0x233
panic({0xf4470e0?, 0xfd673c0?})
	/Users/swarming/.swarming/w/ir/x/w/goroot/src/runtime/panic.go:787 +0x132
go/types.(*Named).Obj(...)
	/Users/swarming/.swarming/w/ir/x/w/goroot/src/go/types/named.go:308
golang.org/x/tools/internal/analysisinternal.IsTypeNamed({0xf5b9980?, 0x0?}, {0xf01bba6, 0x4}, {0xc036fcc998, 0x1, 0xe8b72e8?})
	/Users/swarming/.swarming/w/ir/x/w/targetrepo564898521/internal/analysisinternal/analysis.go:305 +0x89
golang.org/x/tools/internal/analysisinternal.IsMethodNamed({0xf5ccff8?, 0xc03cdf9200?}, {0xf01bba6, 0x4}, {0xf01c79a, 0x4}, {0xc036fccb00, 0x1, 0xc006f98808?})
	/Users/swarming/.swarming/w/ir/x/w/targetrepo564898521/internal/analysisinternal/analysis.go:339 +0xf8
golang.org/x/tools/go/analysis/passes/timeformat.run.func1({0xf5b9020?, 0xc0296d8140})
	/Users/swarming/.swarming/w/ir/x/w/targetrepo564898521/go/analysis/passes/timeformat/timeformat.go:53 +0xae
golang.org/x/tools/go/ast/inspector.(*Inspector).Preorder(0xc03b883950, {0xc036fccb90?, 0x13ae9eb8?, 0x13ae9eb806f98808?}, 0xc036fccba0)
	/Users/swarming/.swarming/w/ir/x/w/targetrepo564898521/go/ast/inspector/inspector.go:96 +0x8f
golang.org/x/tools/go/analysis/passes/timeformat.run(0xc00ffafc00)
	/Users/swarming/.swarming/w/ir/x/w/targetrepo564898521/go/analysis/passes/timeformat/timeformat.go:50 +0x8b
golang.org/x/tools/gopls/internal/cache.(*action).exec.func7(0xfd86400, 0xc036fccd48, 0xc00ffafc00, 0xc036fccd10)
	/Users/swarming/.swarming/w/ir/x/w/targetrepo564898521/gopls/internal/cache/analysis.go:1209 +0x97
golang.org/x/tools/gopls/internal/cache.(*action).exec(0xc03d2087e0, {0xf5be7c0, 0xc0347fca50})
	/Users/swarming/.swarming/w/ir/x/w/targetrepo564898521/gopls/internal/cache/analysis.go:1210 +0xb1c
golang.org/x/tools/gopls/internal/cache.execActions.func1.1()
	/Users/swarming/.swarming/w/ir/x/w/targetrepo564898521/gopls/internal/cache/analysis.go:909 +0x52
sync.(*Once).doSlow(0x0?, 0xc036fccf98?)
	/Users/swarming/.swarming/w/ir/x/w/goroot/src/sync/once.go:78 +0xab
sync.(*Once).Do(...)
	/Users/swarming/.swarming/w/ir/x/w/goroot/src/sync/once.go:69
golang.org/x/tools/gopls/internal/cache.execActions.func1()
	/Users/swarming/.swarming/w/ir/x/w/targetrepo564898521/gopls/internal/cache/analysis.go:907 +0x85
created by golang.org/x/tools/gopls/internal/cache.execActions in goroutine 86469
	/Users/swarming/.swarming/w/ir/x/w/targetrepo564898521/gopls/internal/cache/analysis.go:905 +0x55
FAIL	golang.org/x/tools/gopls/internal/test/integration/workspace	187.033s

[adonovan]

Already fixed by @timothy-king in CL 641177.