cmd/vet, x/tools/go/analysis/passes/testinggoroutine: panic during processing of hash/crc32 package

[dmitshur]

There is a problem on tip when the vendored x/tools module is updated to its latest master pseudo-version (as part of #36905).

What did you do?

$ git clone https://go.googlesource.com/go gotip && cd gotip/src
$ ./make.bash
$ export PATH="$(pwd)/../bin:$PATH"
$ (cd cmd; go get -d golang.org/x/tools@master && go mod tidy && go mod vendor)
$ go install cmd/vet
$ go vet hash/crc32

What did you expect to see?

$ go vet hash/crc32
$ echo $?
0

What did you see instead?

$ go vet hash/crc32 
# hash/crc32
panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x18 pc=0x12463b8]

goroutine 72 [running]:
cmd/vendor/golang.org/x/tools/go/analysis/passes/testinggoroutine.goStmtFun(...)
	/Users/gopher/gotip/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/testinggoroutine/testinggoroutine.go:130
cmd/vendor/golang.org/x/tools/go/analysis/passes/testinggoroutine.checkGoStmt(0xc0001e48f0, 0xc000220a50)
	/Users/gopher/gotip/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/testinggoroutine/testinggoroutine.go:142 +0x58
cmd/vendor/golang.org/x/tools/go/analysis/passes/testinggoroutine.run.func1.1({0x1310528, 0xc000220a50})
	/Users/gopher/gotip/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/testinggoroutine/testinggoroutine.go:76 +0x36
go/ast.inspector.Visit(0xc000053200, {0x1310528, 0xc000220a50})
	/Users/gopher/gotip/src/go/ast/walk.go:387 +0x31
go/ast.Walk({0x130c7c0, 0xc000053200}, {0x1310528, 0xc000220a50})
	/Users/gopher/gotip/src/go/ast/walk.go:52 +0x62
go/ast.walkStmtList({0x130c7c0, 0xc000053200}, {0xc0002252c0, 0x3, 0x0})
	/Users/gopher/gotip/src/go/ast/walk.go:32 +0x91
go/ast.Walk({0x130c7c0, 0xc000053200}, {0x1310140, 0xc000228420})
	/Users/gopher/gotip/src/go/ast/walk.go:235 +0x1945
go/ast.Walk({0x130c7c0, 0xc000053200}, {0x1310460, 0xc000228450})
	/Users/gopher/gotip/src/go/ast/walk.go:358 +0x85c
go/ast.Inspect(...)
	/Users/gopher/gotip/src/go/ast/walk.go:399
cmd/vendor/golang.org/x/tools/go/analysis/passes/testinggoroutine.run.func1({0x1310460, 0xc000228450}, 0xaa)
	/Users/gopher/gotip/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/testinggoroutine/testinggoroutine.go:70 +0xa5
cmd/vendor/golang.org/x/tools/go/ast/inspector.(*Inspector).Nodes(0xc0000a4810, {0xc000538cc8, 0x7, 0x105c47c}, 0xc000538cb8)
	/Users/gopher/gotip/src/cmd/vendor/golang.org/x/tools/go/ast/inspector/inspector.go:100 +0x9c
cmd/vendor/golang.org/x/tools/go/analysis/passes/testinggoroutine.run(0xc0001e48f0)
	/Users/gopher/gotip/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/testinggoroutine/testinggoroutine.go:58 +0xc5
cmd/vendor/golang.org/x/tools/go/analysis/unitchecker.run.func5.1()
	/Users/gopher/gotip/src/cmd/vendor/golang.org/x/tools/go/analysis/unitchecker/unitchecker.go:352 +0x82e
sync.(*Once).doSlow(0x1270b00, 0xc0004f1ad0)
	/Users/gopher/gotip/src/sync/once.go:68 +0xc2
sync.(*Once).Do(...)
	/Users/gopher/gotip/src/sync/once.go:59
cmd/vendor/golang.org/x/tools/go/analysis/unitchecker.run.func5(0x14914e0)
	/Users/gopher/gotip/src/cmd/vendor/golang.org/x/tools/go/analysis/unitchecker/unitchecker.go:304 +0x1a5
cmd/vendor/golang.org/x/tools/go/analysis/unitchecker.run.func6.1(0x0)
	/Users/gopher/gotip/src/cmd/vendor/golang.org/x/tools/go/analysis/unitchecker/unitchecker.go:364 +0x29
created by cmd/vendor/golang.org/x/tools/go/analysis/unitchecker.run.func6
	/Users/gopher/gotip/src/cmd/vendor/golang.org/x/tools/go/analysis/unitchecker/unitchecker.go:363 +0x47

[dmitshur]

Bisection shows this problem is introduced in CL 338529:

$ (cd cmd; go get -d golang.org/x/tools@3fce476f0a782aeb5034d592c189e63be4ba6c9e && go mod tidy && go mod vendor)  # its parent commit
$ go install cmd/vet
$ go vet hash/crc32
$ # ok
$ (cd cmd; go get -d golang.org/x/tools@8fae06a8855e36cf89c791f437aafe2cf3933be5 && go mod tidy && go mod vendor)
$ go install cmd/vet
$ go vet hash/crc32
# hash/crc32
panic: runtime error: [...]

CC @cuonglm, @taking, @odeke-em.

[gopherbot]

Change https://golang.org/cl/347089 mentions this issue: go/analysis/passes/testinggoroutine: fix panic in goStmtFun

[gopherbot]

Change https://golang.org/cl/347191 mentions this issue: all: update vendored dependencies for Go 1.18

[timothy-king]

@dmitshur I believe 338529 is 1.18 only so we will not need to backport a fix. Can you confirm this?

[dmitshur]

@timothy-king Correct. Go 1.17 and 1.16 do not have this problem.

[gopherbot]

Change https://golang.org/cl/348409 mentions this issue: all: update vendored golang.org/x/tools