go/types, types2: gopls crash in recordTypeAndValue

[sxwebdev]

gopls version: v0.8.0 (devel go1.19-c9b60632eb Fri Mar 4 14:10:38 2022 0000)
gopls flags:
update flags: proxy
extension version: 0.32.0
go version: devel 1.19-c9b60632eb
environment: Visual Studio Code darwin
initialization error: undefined
issue timestamp: Sat, 12 Mar 2022 09:33:04 GMT
restart history:
Sat, 12 Mar 2022 09:24:24 GMT: activation (enabled: true)

ATTENTION: PLEASE PROVIDE THE DETAILS REQUESTED BELOW.

Describe what you observed.

panic: assertion failed

goroutine 1358 [running]:
go/types.(*Checker).handleBailout(0xc0022c28c0, 0xc002aed650)
	  check.go:303  0x8b
panic({0x1873ce0, 0x1bf6cf0})
	  panic.go:838  0x207
go/types.assert(...)
	  errors.go:21
go/types.(*Checker).recordTypeAndValue(0xc0022c28c0%3F, {0x1bfe410%3F, 0xc00102af60%3F}, 0x4%3F, {0x1bfc4f0%3F, 0xc002ab6fc0%3F}, {0x1c001e0%3F, 0x209df00%3F})
	  check.go:454  0x1f6
go/types.(*Checker).updateExprType0(0xc0022c28c0, {0xc002af0940%3F, 0x1bfc4f0%3F}, {0x1bfe410%3F, 0xc00102af60}, {0x1bfc4f0%3F, 0xc002ab6fc0%3F}, 0x0)
	  expr.go:593  0x831
go/types.(*Checker).updateExprType(...)
	  expr.go:476
go/types.(*Checker).convertUntyped(0xc0022c28c0, 0xc002af0940, {0x1bfc4f0, 0xc002ab6fc0})
	  expr.go:622  0x2b3
go/types.(*Checker).binary(0xa%3F, 0xc002af0900, {0x1bfe440%3F, 0xc0012868a0}, {0x1bfe7d0%3F, 0xc00102af00}, {0x1bfe410%3F, 0xc00102af60}, 0x27, 0xfd)
	  expr.go:1106  0x1f9
go/types.(*Checker).exprInternal(0xc0022c28c0, 0xc002af0900, {0x1bfe440%3F, 0xc0012868a0}, {0x0%3F, 0x0%3F})
	  expr.go:1624  0xa3f
go/types.(*Checker).rawExpr(0xc000600000%3F, 0xc002af0900%3F, {0x1bfe440%3F, 0xc0012868a0%3F}, {0x0%3F, 0x0%3F}, 0x0)
	  expr.go:1208  0x45
go/types.(*Checker).expr(0xc0022c28c0%3F, 0x0%3F, {0x1bfe440%3F, 0xc0012868a0%3F})
	  expr.go:1704  0x35
go/types.(*Checker).stmt(0xc0022c28c0, 0x0, {0x1bfe800%3F, 0xc0009c7600%3F})
	  stmt.go:567  0x2630
go/types.(*Checker).stmtList(0xc0022c28c0%3F, 0x0, {0xc00102b040%3F, 0x0%3F, 0xc002ab04c8%3F})
	  stmt.go:125  0xc9
go/types.(*Checker).funcBody(0xc0022c28c0, 0xc001ea52c0, {0x0%3F, 0xc002aed5f0%3F}, 0xc002af0480, 0xc001286900, {0x0, 0x0})
	  stmt.go:46  0x285
go/types.(*Checker).funcDecl.func1()
	  decl.go:788  0x45
go/types.(*Checker).processDelayed(0xc0022c28c0, 0x0)
	  check.go:388  0x39
go/types.(*Checker).checkFiles(0xc0022c28c0, {0xc002aa65c0%3F, 0xc002a93d60%3F, 0x0%3F})
	  check.go:336  0xcb
go/types.(*Checker).Files(...)
	  check.go:308
golang.org/x/tools/internal/lsp/cache.doTypeCheck({0x1bffbf8, 0xc002a89f40}, 0xc002478000, 0xc000a46f00, 0x2, 0xc002ab69f0, 0x1bfef80%3F)
	  check.go:551  0x97b
golang.org/x/tools/internal/lsp/cache.typeCheck({0x1bffbf8, 0xc002a89f40}, 0xc002478000, 0xc000a46f00, 0x2, 0xc002ab69f0%3F)
	  check.go:317  0xe5
golang.org/x/tools/internal/lsp/cache.(*snapshot).buildPackageHandle.func1({0x1bffbf8%3F, 0xc002a89f40}, {0x1bf9340%3F, 0xc002478000})
	  check.go:125  0x233
golang.org/x/tools/internal/memoize.(*Handle).run.func1()
	  memoize.go:327  0xa9
created by golang.org/x/tools/internal/memoize.(*Handle).run
	  memoize.go:320  0x1b8
[Error - 12:32:54] 

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[findleyr]

Hi, this looks like it could be a type checker bug.

Do you recall the code you were working on when this crash occurred?

[findleyr]

Transferring to the go issue tracker.

[findleyr]

CC @griesemer

[sxwebdev]

Hi, this looks like it could be a type checker bug.

Do you recall the code you were working on when this crash occurred?

Yes. You can remove the word interface next to the FloatType

package utils

type FloatType interface {
	float32 | float64
}

type IntegerType interface {
	int8 | int16 | int32 | int64 | int |
		uint8 | uint16 | uint32 | uint64 | uint
}

type ComplexType interface {
	complex64 | complex128
}

type Number interface {
	FloatType | IntegerType | ComplexType
}

[findleyr]

Thanks for your reply. I'm not able to naively reproduce this. Can you share code that is using FloatType? The error may be occurring at the site of usage.

I'll try to look into the panicking stack to see if I can reconstruct.

[sxwebdev]

I don't use the FloatType directly. But I have a function that uses the type Number

package utils

func GetDefaultNumber[T Number](value, defaultValue T) T {
	if value == 0 {
		return defaultValue
	}
	return value
}

[findleyr]

Thanks, with that function I am able to reproduce!

[sxwebdev]

Excellent!)

[griesemer]

Minimized reproducer (for types2):

package p

type FloatType {
	float64
}

func _[T FloatType | int](x T) {
	_ = x == 0 
}

[gopherbot]

Change https://go.dev/cl/392575 mentions this issue: go/types, types2: use correct underlying type in union set computation

[findleyr]

@gopherbot please backport this to 1.18, it's a deterministic panic.

[gopherbot]

Backport issue(s) opened: #51665 (for 1.18).

Remember to create the cherry-pick CL(s) as soon as the patch is submitted to master, according to https://go.dev/wiki/MinorReleases.