cmd/compile: "internal compiler error: mayCall" in method of parameterized type

[jayconrod]

What version of Go are you using (go version)?

$ go version
go version devel go1.18-8486ced8b0 Mon Aug 23 17:51:41 2021 +0000 linux/amd64

Does this issue reproduce with the latest release?

n/a

What operating system and processor architecture are you using (go env)?

go env Output

$ go env
GO111MODULE=""
GOARCH="amd64"
GOBIN=""
GOCACHE="/home/jay/.cache/go-build"
GOENV="/home/jay/.config/go/env"
GOEXE=""
GOEXPERIMENT=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOINSECURE=""
GOMODCACHE="/home/jay/.cache/gomodcache"
GONOPROXY=""
GONOSUMDB=""
GOOS="linux"
GOPATH="/home/jay/go"
GOPRIVATE=""
GOPROXY="https://proxy.golang.org,direct"
GOROOT="/home/jay/Code/goroot"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/home/jay/Code/goroot/pkg/tool/linux_amd64"
GOVCS=""
GOVERSION="devel go1.18-8486ced8b0 Mon Aug 23 17:51:41 2021 +0000"
GCCGO="gccgo"
AR="ar"
CC="gcc"
CXX="g++"
CGO_ENABLED="1"
GOMOD="/home/jay/Code/goroot/src/cmd/go.mod"
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-fPIC -m64 -pthread -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build4153403543=/tmp/go-build -gno-record-gcc-switches"

What did you do?

• Added type parameters to cmd/go/internal/work.Cache. See CL 344513, PS1.
• Ran go test cmd/go/internal/par.

What did you expect to see?

Tests pass

What did you see instead?

# cmd/go/internal/par [cmd/go/internal/par.test]
internal/par/cache.go:92:14: internal compiler error: mayCall 
.   DYNAMICDOTTYPE tc(1) .shape.int # cache.go:92:14 .shape.int
.   .   NAME-par.key esc(no) tc(1) Class:PPARAM Offset:0 OnStack INTER-interface {} # cache.go:91:17
.   DYNAMICDOTTYPE-T
.   .   INDEX tc(1) Bounded PTR-*uint8 # cache.go:92:14 PTR-*uint8
.   .   .   DEREF tc(1) ARRAY-[5]uintptr # cache.go:92:14 ARRAY-[5]uintptr
.   .   .   .   CONVNOP tc(1) PTR-*[5]uintptr # cache.go:92:14 PTR-*[5]uintptr
.   .   .   .   .   CONVNOP tc(1) UNSAFEPTR-unsafe.Pointer # cache.go:92:14 UNSAFEPTR-unsafe.Pointer
.   .   .   .   .   .   NAME-par..dict esc(no) tc(1) Class:PAUTO Offset:0 OnStack uintptr # cache.go:91:12
.   .   .   LITERAL-0 tc(1) uintptr # cache.go:91:12

goroutine 1 [running]:
runtime/debug.Stack()
        /home/jay/Code/goroot/src/runtime/debug/stack.go:24 +0x65
cmd/compile/internal/base.FatalfAt({0x9eede0, 0xc0}, {0xcefdb7, 0xb}, {0xc0000b90d0, 0x1, 0x1})
        /home/jay/Code/goroot/src/cmd/compile/internal/base/print.go:227 +0x154
cmd/compile/internal/walk.mayCall.func2({0xe61e68, 0xc0009eede0})
        /home/jay/Code/goroot/src/cmd/compile/internal/walk/walk.go:308 +0x3c9
cmd/compile/internal/ir.Any.func1({0xe61e68, 0xc0009eede0})
        /home/jay/Code/goroot/src/cmd/compile/internal/ir/visit.go:130 +0x30
cmd/compile/internal/ir.Any({0xe61e68, 0xc0009eede0}, 0xc00078f9e0)
        /home/jay/Code/goroot/src/cmd/compile/internal/ir/visit.go:132 +0xb8
cmd/compile/internal/walk.mayCall({0xe61e68, 0xc0009eede0})
        /home/jay/Code/goroot/src/cmd/compile/internal/walk/walk.go:299 +0x73
cmd/compile/internal/walk.walkCall1(0xc0009dd4d0, 0xc0000b9828)
        /home/jay/Code/goroot/src/cmd/compile/internal/walk/expr.go:583 +0x2f8
cmd/compile/internal/walk.walkCall(0xc0009dd4d0, 0x2)
        /home/jay/Code/goroot/src/cmd/compile/internal/walk/expr.go:553 +0x6b2
cmd/compile/internal/walk.walkExpr1({0xe61698, 0xc0009dd4d0}, 0xc0009dd4d0)
        /home/jay/Code/goroot/src/cmd/compile/internal/walk/expr.go:176 +0x485
cmd/compile/internal/walk.walkExpr({0xe61698, 0xc0009dd4d0}, 0xc0000b9828)
        /home/jay/Code/goroot/src/cmd/compile/internal/walk/expr.go:55 +0x428
cmd/compile/internal/walk.walkAssign(0xc0000b9828, {0xe612b0, 0xc00037f9f0})
        /home/jay/Code/goroot/src/cmd/compile/internal/walk/assign.go:72 +0x9dc
cmd/compile/internal/walk.walkExpr1({0xe612b0, 0xc00037f9f0}, 0xc00037f9f0)
        /home/jay/Code/goroot/src/cmd/compile/internal/walk/expr.go:179 +0x43f
cmd/compile/internal/walk.walkExpr({0xe612b0, 0xc00037f9f0}, 0xc0000b9828)
        /home/jay/Code/goroot/src/cmd/compile/internal/walk/expr.go:55 +0x428
cmd/compile/internal/walk.walkStmt({0xe612b0, 0xc00037f9f0})
        /home/jay/Code/goroot/src/cmd/compile/internal/walk/stmt.go:57 +0x5da
cmd/compile/internal/walk.walkStmtList({0xc00078f980, 0x1, 0xc00037fa40})
        /home/jay/Code/goroot/src/cmd/compile/internal/walk/stmt.go:167 +0x5b
cmd/compile/internal/walk.walkExpr({0xe61c10, 0xc00037fa40}, 0xc0009f4470)
        /home/jay/Code/goroot/src/cmd/compile/internal/walk/expr.go:37 +0xef
cmd/compile/internal/walk.walkIf(0xc0009f4460)
        /home/jay/Code/goroot/src/cmd/compile/internal/walk/stmt.go:219 +0x31
cmd/compile/internal/walk.walkStmt({0xe62318, 0xc0009f4460})
        /home/jay/Code/goroot/src/cmd/compile/internal/walk/stmt.go:131 +0x2fc
cmd/compile/internal/walk.walkStmtList({0xc00042c940, 0x3, 0xc0009c74a0})
        /home/jay/Code/goroot/src/cmd/compile/internal/walk/stmt.go:167 +0x5b
cmd/compile/internal/walk.Walk(0xc0009c74a0)
        /home/jay/Code/goroot/src/cmd/compile/internal/walk/walk.go:43 +0xef
cmd/compile/internal/gc.prepareFunc(0xc0009c74a0)
        /home/jay/Code/goroot/src/cmd/compile/internal/gc/compile.go:92 +0x6d
cmd/compile/internal/gc.enqueueFunc(0xc0009c7340)
        /home/jay/Code/goroot/src/cmd/compile/internal/gc/compile.go:66 +0x2f7
cmd/compile/internal/gc.Main(0xd1bee0)
        /home/jay/Code/goroot/src/cmd/compile/internal/gc/main.go:296 +0xe77
main.main()
        /home/jay/Code/goroot/src/cmd/compile/main.go:55 +0xdd

FAIL    cmd/go/internal/par [build failed]
FAIL

[griesemer]

Simpler reproducer. Compiling

package p

import "sync"

type Cache[K, V any] struct {
	m sync.Map
}

func (c *Cache[K, V]) foo(x interface{}, f func(K) bool) {
	f(x.(K))
}

var _ Cache[int, int]

produces:

$ go tool compile x.go2
x.go2:10:5: internal compiler error: mayCall 
.   DYNAMICDOTTYPE tc(1) .shape.int # x.go2:10:5 .shape.int
.   .   NAME-p.x esc(no) tc(1) Class:PPARAM Offset:0 OnStack INTER-interface {} # x.go2:9:27
.   DYNAMICDOTTYPE-T
.   .   INDEX tc(1) Bounded PTR-*uint8 # x.go2:10:5 PTR-*uint8
.   .   .   DEREF tc(1) ARRAY-[4]uintptr # x.go2:10:5 ARRAY-[4]uintptr
.   .   .   .   CONVNOP tc(1) PTR-*[4]uintptr # x.go2:10:5 PTR-*[4]uintptr
.   .   .   .   .   CONVNOP tc(1) UNSAFEPTR-unsafe.Pointer # x.go2:10:5 UNSAFEPTR-unsafe.Pointer
.   .   .   .   .   .   NAME-p..dict esc(no) tc(1) Class:PPARAM Offset:0 OnStack uintptr # x.go2:9:6
.   .   .   LITERAL-0 tc(1) uintptr # x.go2:9:6

goroutine 1 [running]:
runtime/debug.Stack()
	/Users/gri/goroot/src/runtime/debug/stack.go:24 +0x65
cmd/compile/internal/base.FatalfAt({0x430900, 0xc0}, {0x18ed445, 0xb}, {0xc0004295b8, 0x1, 0x1})
	/Users/gri/goroot/src/cmd/compile/internal/base/print.go:227 +0x154
cmd/compile/internal/walk.mayCall.func2({0x1a5f428, 0xc000430900})
	/Users/gri/goroot/src/cmd/compile/internal/walk/walk.go:308 +0x3c9
cmd/compile/internal/ir.Any.func1({0x1a5f428, 0xc000430900})
	/Users/gri/goroot/src/cmd/compile/internal/ir/visit.go:130 +0x30
cmd/compile/internal/ir.Any({0x1a5f428, 0xc000430900}, 0xc000061890)
	/Users/gri/goroot/src/cmd/compile/internal/ir/visit.go:132 +0xb8
cmd/compile/internal/walk.mayCall({0x1a5f428, 0xc000430900})
	/Users/gri/goroot/src/cmd/compile/internal/walk/walk.go:299 +0x73
cmd/compile/internal/walk.walkCall1(0xc00044c120, 0xc000429a80)
	/Users/gri/goroot/src/cmd/compile/internal/walk/expr.go:583 +0x2f8
cmd/compile/internal/walk.walkCall(0xc00044c120, 0x0)
	/Users/gri/goroot/src/cmd/compile/internal/walk/expr.go:553 +0x6b2
cmd/compile/internal/walk.walkExpr1({0x1a5ec58, 0xc00044c120}, 0xc00044c120)
	/Users/gri/goroot/src/cmd/compile/internal/walk/expr.go:176 +0x485
cmd/compile/internal/walk.walkExpr({0x1a5ec58, 0xc00044c120}, 0xc000429a80)
	/Users/gri/goroot/src/cmd/compile/internal/walk/expr.go:55 +0x428
cmd/compile/internal/walk.walkStmt({0x1a5ec58, 0xc00044c120})
	/Users/gri/goroot/src/cmd/compile/internal/walk/stmt.go:57 +0x5da
cmd/compile/internal/walk.walkStmtList({0xc000061880, 0x1, 0xc000444b00})
	/Users/gri/goroot/src/cmd/compile/internal/walk/stmt.go:167 +0x5b
cmd/compile/internal/walk.Walk(0xc000444b00)
	/Users/gri/goroot/src/cmd/compile/internal/walk/walk.go:43 +0xef
cmd/compile/internal/gc.prepareFunc(0xc000444b00)
	/Users/gri/goroot/src/cmd/compile/internal/gc/compile.go:92 +0x6d
cmd/compile/internal/gc.enqueueFunc(0xc000444b00)
	/Users/gri/goroot/src/cmd/compile/internal/gc/compile.go:66 +0x2f7
cmd/compile/internal/gc.Main(0x1919338)
	/Users/gri/goroot/src/cmd/compile/internal/gc/main.go:296 +0xe77
main.main()
	/Users/gri/goroot/src/cmd/compile/main.go:55 +0xdd

[griesemer]

Even simpler reproducer:

package p

type Cache[K any] struct {}

func (c Cache[K]) foo(x interface{}, f func(K) bool) {
	f(x.(K))
}

var _ Cache[int]

For reference, this version compiles fine:

package p

func foo[K any](x interface{}, f func(K) bool) {
	f(x.(K))
}

[danscales]

@randall77 Do you want to look at this, since it involves DYNAMICDOTTYPE? Seems like we probably just add DYNAMICDOTTYPE in with the case with DOTTYPE in function walk.go:mayCall(), since DYNAMICDOTTYPE can also panic, like all the other ops in that case.

[gopherbot]

Change https://golang.org/cl/344571 mentions this issue: cmd/compile: mark ODYNAMICDOTTYPE as an expression that can panic