cmd/compile: compiler crashes with a 10MB error message when building tiny program on -c=4

[ALTree]

$ gotip version
go version devel +8db4d02e8f Fri Apr 28 07:27:25 2017 +0000 linux/amd64

The following program:

package p

func Foo() {
	_ = (make([]func() interface {
		M(interface{})
	}, 1))
}

when built on loop on my 4-core machine with -c=4:

while true; do gotip build -gcflags -c=4 main.go; done

crashes the compiler with a 10MB error message. The error starts with this:

# command-line-arguments
<autogenerated>:1:0: internal compiler error: <autogenerated>:1:0: internal compiler error: <autogenerated>:1:0: internal compiler error: <autogenerated>:1:0: internal compiler error: <autogenerated>:1:0: internal compiler error

and ends with this:

internal compiler error: runtime: goroutine stack exceeds 1000000000-byte limit
fatal error: stack overflow

Then a stacktrace follows:

fatal error: stack overflow

runtime stack:
runtime.throw(0xb9a69e, 0xe)
	/home/alberto/go/src/runtime/panic.go:596 +0x95
runtime.newstack(0x0)
	/home/alberto/go/src/runtime/stack.go:1059 +0x3da
runtime.morestack()
	/home/alberto/go/src/runtime/asm_amd64.s:405 +0x86

goroutine 9 [running]:
bufio.(*Writer).Flush(0xc420018380, 0x0, 0x0)
	/home/alberto/go/src/bufio/bufio.go:559 +0x1f3 fp=0xc440520370 sp=0xc440520368
cmd/compile/internal/gc.flusherrors()
	/home/alberto/go/src/cmd/compile/internal/gc/subr.go:71 +0x35 fp=0xc4405203f0 sp=0xc440520370
cmd/compile/internal/gc.Fatalf(0xba0a49, 0x18, 0xc440520548, 0x1, 0x1)
	/home/alberto/go/src/cmd/compile/internal/gc/subr.go:167 +0x26 fp=0xc440520460 sp=0xc4405203f0
cmd/compile/internal/gc.dowidth(0xc420051d40)
	/home/alberto/go/src/cmd/compile/internal/gc/align.go:186 +0xfb0 fp=0xc440520598 sp=0xc440520460
cmd/compile/internal/types.(*Type).Fields(0xc420051d40, 0x0)
	/home/alberto/go/src/cmd/compile/internal/types/type.go:792 +0x84 fp=0xc4405205d8 sp=0xc440520598
cmd/compile/internal/types.(*Fields).Len(...)
	/home/alberto/go/src/cmd/compile/internal/types/type.go:1215
cmd/compile/internal/types.(*Type).NumFields(0xc420051d40, 0x0)
	/home/alberto/go/src/cmd/compile/internal/types/type.go:1215 +0x2b fp=0xc4405205f8 sp=0xc4405205d8
cmd/compile/internal/types.(*Type).IsEmptyInterface(0xc420051d40, 0x0)
	/home/alberto/go/src/cmd/compile/internal/types/type.go:1202 +0x44 fp=0xc440520618 sp=0xc4405205f8
cmd/compile/internal/gc.typefmt(0xc420051d40, 0x0, 0x0, 0x1, 0x0, 0x0)
	/home/alberto/go/src/cmd/compile/internal/gc/fmt.go:775 +0x1e79 fp=0xc4405208e8 sp=0xc440520618
cmd/compile/internal/gc.tconv(0xc420051d40, 0x0, 0x0, 0x0, 0x0, 0x0)
	/home/alberto/go/src/cmd/compile/internal/gc/fmt.go:1809 +0x7a fp=0xc440520928 sp=0xc4405208e8
cmd/compile/internal/gc.typeFormat(0xc420051d40, 0xef87e0, 0xc425525a40, 0xc400000076, 0x0)
	/home/alberto/go/src/cmd/compile/internal/gc/fmt.go:1787 +0x92 fp=0xc4405209d0 sp=0xc440520928
cmd/compile/internal/gc.Main.func4(0xc420051d40, 0xef87e0, 0xc425525a40, 0xc400000076, 0x0)
	/home/alberto/go/src/cmd/compile/internal/gc/main.go:393 +0x51 fp=0xc440520a08 sp=0xc4405209d0
cmd/compile/internal/types.(*Type).Format(0xc420051d40, 0xef87e0, 0xc425525a40, 0x76)
	/home/alberto/go/src/cmd/compile/internal/types/utils.go:67 +0x5a fp=0xc440520a40 sp=0xc440520a08
fmt.(*pp).handleMethods(0xc425525a40, 0xc400000076, 0x1)
	/home/alberto/go/src/fmt/print.go:563 +0x49d fp=0xc440520ad0 sp=0xc440520a40
fmt.(*pp).printArg(0xc425525a40, 0xb8b9a0, 0xc420051d40, 0x76)
	/home/alberto/go/src/fmt/print.go:679 +0x185 fp=0xc440520b50 sp=0xc440520ad0
fmt.(*pp).doPrintf(0xc425525a40, 0xba0a49, 0x18, 0xc440520ea0, 0x1, 0x1)
	/home/alberto/go/src/fmt/print.go:996 +0x169 fp=0xc440520c80 sp=0xc440520b50
fmt.Fprintf(0xef39a0, 0xc42000c018, 0xba0a49, 0x18, 0xc440520ea0, 0x1, 0x1, 0x2e, 0x0, 0x0)
	/home/alberto/go/src/fmt/print.go:181 +0x76 fp=0xc440520ce8 sp=0xc440520c80
fmt.Printf(0xba0a49, 0x18, 0xc440520ea0, 0x1, 0x1, 0x2e, 0x0, 0x0)
	/home/alberto/go/src/fmt/print.go:190 +0x72 fp=0xc440520d48 sp=0xc440520ce8
cmd/compile/internal/gc.Fatalf(0xba0a49, 0x18, 0xc440520ea0, 0x1, 0x1)
	/home/alberto/go/src/cmd/compile/internal/gc/subr.go:170 +0x106 fp=0xc440520db8 sp=0xc440520d48
cmd/compile/internal/gc.dowidth(0xc420051d40)
	/home/alberto/go/src/cmd/compile/internal/gc/align.go:186 +0xfb0 fp=0xc440520ef0 sp=0xc440520db8
cmd/compile/internal/types.(*Type).Fields(0xc420051d40, 0x0)
	/home/alberto/go/src/cmd/compile/internal/types/type.go:792 +0x84 fp=0xc440520f30 sp=0xc440520ef0
cmd/compile/internal/types.(*Fields).Len(...)
	/home/alberto/go/src/cmd/compile/internal/types/type.go:1215
cmd/compile/internal/types.(*Type).NumFields(0xc420051d40, 0x0)
	/home/alberto/go/src/cmd/compile/internal/types/type.go:1215 +0x2b fp=0xc440520f50 sp=0xc440520f30
cmd/compile/internal/types.(*Type).IsEmptyInterface(0xc420051d40, 0x0)
	/home/alberto/go/src/cmd/compile/internal/types/type.go:1202 +0x44 fp=0xc440520f70 sp=0xc440520f50
cmd/compile/internal/gc.typefmt(0xc420051d40, 0x0, 0x0, 0x1, 0x0, 0x0)
	/home/alberto/go/src/cmd/compile/internal/gc/fmt.go:775 +0x1e79 fp=0xc440521240 sp=0xc440520f70
cmd/compile/internal/gc.tconv(0xc420051d40, 0x0, 0x0, 0x0, 0x0, 0x0)
	/home/alberto/go/src/cmd/compile/internal/gc/fmt.go:1809 +0x7a fp=0xc440521280 sp=0xc440521240
cmd/compile/internal/gc.typeFormat(0xc420051d40, 0xef87e0, 0xc425525980, 0xc400000076, 0x0)
	/home/alberto/go/src/cmd/compile/internal/gc/fmt.go:1787 +0x92 fp=0xc440521328 sp=0xc440521280
cmd/compile/internal/gc.Main.func4(0xc420051d40, 0xef87e0, 0xc425525980, 0xc400000076, 0x0)
	/home/alberto/go/src/cmd/compile/internal/gc/main.go:393 +0x51 fp=0xc440521360 sp=0xc440521328
cmd/compile/internal/types.(*Type).Format(0xc420051d40, 0xef87e0, 0xc425525980, 0x76)
	/home/alberto/go/src/cmd/compile/internal/types/utils.go:67 +0x5a fp=0xc440521398 sp=0xc440521360
fmt.(*pp).handleMethods(0xc425525980, 0xc400000076, 0x1)
	/home/alberto/go/src/fmt/print.go:563 +0x49d fp=0xc440521428 sp=0xc440521398
fmt.(*pp).printArg(0xc425525980, 0xb8b9a0, 0xc420051d40, 0x76)
	/home/alberto/go/src/fmt/print.go:679 +0x185 fp=0xc4405214a8 sp=0xc440521428
fmt.(*pp).doPrintf(0xc425525980, 0xba0a49, 0x18, 0xc4405217f8, 0x1, 0x1)
	/home/alberto/go/src/fmt/print.go:996 +0x169 fp=0xc4405215d8 sp=0xc4405214a8
fmt.Fprintf(0xef39a0, 0xc42000c018, 0xba0a49, 0x18, 0xc4405217f8, 0x1, 0x1, 0x2e, 0x0, 0x0)
	/home/alberto/go/src/fmt/print.go:181 +0x76 fp=0xc440521640 sp=0xc4405215d8
fmt.Printf(0xba0a49, 0x18, 0xc4405217f8, 0x1, 0x1, 0x2e, 0x0, 0x0)
	/home/alberto/go/src/fmt/print.go:190 +0x72 fp=0xc4405216a0 sp=0xc440521640
cmd/compile/internal/gc.Fatalf(0xba0a49, 0x18, 0xc4405217f8, 0x1, 0x1)
	/home/alberto/go/src/cmd/compile/internal/gc/subr.go:170 +0x106 fp=0xc440521710 sp=0xc4405216a0
cmd/compile/internal/gc.dowidth(0xc420051d40)
	/home/alberto/go/src/cmd/compile/internal/gc/align.go:186 +0xfb0 fp=0xc440521848 sp=0xc440521710
cmd/compile/internal/types.(*Type).Fields(0xc420051d40, 0x0)
	/home/alberto/go/src/cmd/compile/internal/types/type.go:792 +0x84 fp=0xc440521888 sp=0xc440521848
cmd/compile/internal/types.(*Fields).Len(...)
	/home/alberto/go/src/cmd/compile/internal/types/type.go:1215
cmd/compile/internal/types.(*Type).NumFields(0xc420051d40, 0x0)
	/home/alberto/go/src/cmd/compile/internal/types/type.go:1215 +0x2b fp=0xc4405218a8 sp=0xc440521888
cmd/compile/internal/types.(*Type).IsEmptyInterface(0xc420051d40, 0x0)
	/home/alberto/go/src/cmd/compile/internal/types/type.go:1202 +0x44 fp=0xc4405218c8 sp=0xc4405218a8
cmd/compile/internal/gc.typefmt(0xc420051d40, 0x0, 0x0, 0x1, 0x0, 0x0)
	/home/alberto/go/src/cmd/compile/internal/gc/fmt.go:775 +0x1e79 fp=0xc440521b98 sp=0xc4405218c8
cmd/compile/internal/gc.tconv(0xc420051d40, 0x0, 0x0, 0x0, 0x0, 0x0)
	/home/alberto/go/src/cmd/compile/internal/gc/fmt.go:1809 +0x7a fp=0xc440521bd8 sp=0xc440521b98
cmd/compile/internal/gc.typeFormat(0xc420051d40, 0xef87e0, 0xc4255258c0, 0xc400000076, 0x0)
	/home/alberto/go/src/cmd/compile/internal/gc/fmt.go:1787 +0x92 fp=0xc440521c80 sp=0xc440521bd8
cmd/compile/internal/gc.Main.func4(0xc420051d40, 0xef87e0, 0xc4255258c0, 0xc400000076, 0x0)
	/home/alberto/go/src/cmd/compile/internal/gc/main.go:393 +0x51 fp=0xc440521cb8 sp=0xc440521c80
cmd/compile/internal/types.(*Type).Format(0xc420051d40, 0xef87e0, 0xc4255258c0, 0x76)
	/home/alberto/go/src/cmd/compile/internal/types/utils.go:67 +0x5a fp=0xc440521cf0 sp=0xc440521cb8
fmt.(*pp).handleMethods(0xc4255258c0, 0xc400000076, 0x1)
	/home/alberto/go/src/fmt/print.go:563 +0x49d fp=0xc440521d80 sp=0xc440521cf0
fmt.(*pp).printArg(0xc4255258c0, 0xb8b9a0, 0xc420051d40, 0x76)
	/home/alberto/go/src/fmt/print.go:679 +0x185 fp=0xc440521e00 sp=0xc440521d80
fmt.(*pp).doPrintf(0xc4255258c0, 0xba0a49, 0x18, 0xc440522150, 0x1, 0x1)
	/home/alberto/go/src/fmt/print.go:996 +0x169 fp=0xc440521f30 sp=0xc440521e00
fmt.Fprintf(0xef39a0, 0xc42000c018, 0xba0a49, 0x18, 0xc440522150, 0x1, 0x1, 0x2e, 0x0, 0x0)
	/home/alberto/go/src/fmt/print.go:181 +0x76 fp=0xc440521f98 sp=0xc440521f30
fmt.Printf(0xba0a49, 0x18, 0xc440522150, 0x1, 0x1, 0x2e, 0x0, 0x0)
	/home/alberto/go/src/fmt/print.go:190 +0x72 fp=0xc440521ff8 sp=0xc440521f98
cmd/compile/internal/gc.Fatalf(0xba0a49, 0x18, 0xc440522150, 0x1, 0x1)
	/home/alberto/go/src/cmd/compile/internal/gc/subr.go:170 +0x106 fp=0xc440522068 sp=0xc440521ff8
cmd/compile/internal/gc.dowidth(0xc420051d40)
	/home/alberto/go/src/cmd/compile/internal/gc/align.go:186 +0xfb0 fp=0xc4405221a0 sp=0xc440522068
cmd/compile/internal/types.(*Type).Fields(0xc420051d40, 0x0)
	/home/alberto/go/src/cmd/compile/internal/types/type.go:792 +0x84 fp=0xc4405221e0 sp=0xc4405221a0
cmd/compile/internal/types.(*Fields).Len(...)
	/home/alberto/go/src/cmd/compile/internal/types/type.go:1215
cmd/compile/internal/types.(*Type).NumFields(0xc420051d40, 0x0)
	/home/alberto/go/src/cmd/compile/internal/types/type.go:1215 +0x2b fp=0xc440522200 sp=0xc4405221e0
cmd/compile/internal/types.(*Type).IsEmptyInterface(0xc420051d40, 0x0)
	/home/alberto/go/src/cmd/compile/internal/types/type.go:1202 +0x44 fp=0xc440522220 sp=0xc440522200
cmd/compile/internal/gc.typefmt(0xc420051d40, 0x0, 0x0, 0x1, 0x0, 0x0)
	/home/alberto/go/src/cmd/compile/internal/gc/fmt.go:775 +0x1e79 fp=0xc4405224f0 sp=0xc440522220
cmd/compile/internal/gc.tconv(0xc420051d40, 0x0, 0x0, 0x0, 0x0, 0x0)
	/home/alberto/go/src/cmd/compile/internal/gc/fmt.go:1809 +0x7a fp=0xc440522530 sp=0xc4405224f0
cmd/compile/internal/gc.typeFormat(0xc420051d40, 0xef87e0, 0xc425525800, 0xc400000076, 0x0)
	/home/alberto/go/src/cmd/compile/internal/gc/fmt.go:1787 +0x92 fp=0xc4405225d8 sp=0xc440522530
cmd/compile/internal/gc.Main.func4(0xc420051d40, 0xef87e0, 0xc425525800, 0xc400000076, 0x0)
	/home/alberto/go/src/cmd/compile/internal/gc/main.go:393 +0x51 fp=0xc440522610 sp=0xc4405225d8
cmd/compile/internal/types.(*Type).Format(0xc420051d40, 0xef87e0, 0xc425525800, 0x76)
	/home/alberto/go/src/cmd/compile/internal/types/utils.go:67 +0x5a fp=0xc440522648 sp=0xc440522610
fmt.(*pp).handleMethods(0xc425525800, 0xc400000076, 0x1)
	/home/alberto/go/src/fmt/print.go:563 +0x49d fp=0xc4405226d8 sp=0xc440522648
fmt.(*pp).printArg(0xc425525800, 0xb8b9a0, 0xc420051d40, 0x76)
	/home/alberto/go/src/fmt/print.go:679 +0x185 fp=0xc440522758 sp=0xc4405226d8
fmt.(*pp).doPrintf(0xc425525800, 0xba0a49, 0x18, 0xc440522aa8, 0x1, 0x1)
	/home/alberto/go/src/fmt/print.go:996 +0x169 fp=0xc440522888 sp=0xc440522758
fmt.Fprintf(0xef39a0, 0xc42000c018, 0xba0a49, 0x18, 0xc440522aa8, 0x1, 0x1, 0x2e, 0x0, 0x0)
	/home/alberto/go/src/fmt/print.go:181 +0x76 fp=0xc4405228f0 sp=0xc440522888
fmt.Printf(0xba0a49, 0x18, 0xc440522aa8, 0x1, 0x1, 0x2e, 0x0, 0x0)
	/home/alberto/go/src/fmt/print.go:190 +0x72 fp=0xc440522950 sp=0xc4405228f0
cmd/compile/internal/gc.Fatalf(0xba0a49, 0x18, 0xc440522aa8, 0x1, 0x1)
	/home/alberto/go/src/cmd/compile/internal/gc/subr.go:170 +0x106 fp=0xc4405229c0 sp=0xc440522950
cmd/compile/internal/gc.dowidth(0xc420051d40)
	/home/alberto/go/src/cmd/compile/internal/gc/align.go:186 +0xfb0 fp=0xc440522af8 sp=0xc4405229c0
cmd/compile/internal/types.(*Type).Fields(0xc420051d40, 0x0)
	/home/alberto/go/src/cmd/compile/internal/types/type.go:792 +0x84 fp=0xc440522b38 sp=0xc440522af8
cmd/compile/internal/types.(*Fields).Len(...)
	/home/alberto/go/src/cmd/compile/internal/types/type.go:1215
cmd/compile/internal/types.(*Type).NumFields(0xc420051d40, 0x0)
	/home/alberto/go/src/cmd/compile/internal/types/type.go:1215 +0x2b fp=0xc440522b58 sp=0xc440522b38
cmd/compile/internal/types.(*Type).IsEmptyInterface(0xc420051d40, 0x0)
	/home/alberto/go/src/cmd/compile/internal/types/type.go:1202 +0x44 fp=0xc440522b78 sp=0xc440522b58
cmd/compile/internal/gc.typefmt(0xc420051d40, 0x0, 0x0, 0x1, 0x0, 0x0)
	/home/alberto/go/src/cmd/compile/internal/gc/fmt.go:775 +0x1e79 fp=0xc440522e48 sp=0xc440522b78
cmd/compile/internal/gc.tconv(0xc420051d40, 0x0, 0x0, 0x0, 0x0, 0x0)
	/home/alberto/go/src/cmd/compile/internal/gc/fmt.go:1809 +0x7a fp=0xc440522e88 sp=0xc440522e48
cmd/compile/internal/gc.typeFormat(0xc420051d40, 0xef87e0, 0xc425525740, 0xc400000076, 0x0)
	/home/alberto/go/src/cmd/compile/internal/gc/fmt.go:1787 +0x92 fp=0xc440522f30 sp=0xc440522e88
cmd/compile/internal/gc.Main.func4(0xc420051d40, 0xef87e0, 0xc425525740, 0xc400000076, 0x0)
	/home/alberto/go/src/cmd/compile/internal/gc/main.go:393 +0x51 fp=0xc440522f68 sp=0xc440522f30
cmd/compile/internal/types.(*Type).Format(0xc420051d40, 0xef87e0, 0xc425525740, 0x76)
	/home/alberto/go/src/cmd/compile/internal/types/utils.go:67 +0x5a fp=0xc440522fa0 sp=0xc440522f68
fmt.(*pp).handleMethods(0xc425525740, 0xc400000076, 0x1)
	/home/alberto/go/src/fmt/print.go:563 +0x49d fp=0xc440523030 sp=0xc440522fa0
fmt.(*pp).printArg(0xc425525740, 0xb8b9a0, 0xc420051d40, 0x76)
	/home/alberto/go/src/fmt/print.go:679 +0x185 fp=0xc4405230b0 sp=0xc440523030
fmt.(*pp).doPrintf(0xc425525740, 0xba0a49, 0x18, 0xc440523400, 0x1, 0x1)
	/home/alberto/go/src/fmt/print.go:996 +0x169 fp=0xc4405231e0 sp=0xc4405230b0
fmt.Fprintf(0xef39a0, 0xc42000c018, 0xba0a49, 0x18, 0xc440523400, 0x1, 0x1, 0x2e, 0x0, 0x0)
	/home/alberto/go/src/fmt/print.go:181 +0x76 fp=0xc440523248 sp=0xc4405231e0
fmt.Printf(0xba0a49, 0x18, 0xc440523400, 0x1, 0x1, 0x2e, 0x0, 0x0)
	/home/alberto/go/src/fmt/print.go:190 +0x72 fp=0xc4405232a8 sp=0xc440523248
cmd/compile/internal/gc.Fatalf(0xba0a49, 0x18, 0xc440523400, 0x1, 0x1)
	/home/alberto/go/src/cmd/compile/internal/gc/subr.go:170 +0x106 fp=0xc440523318 sp=0xc4405232a8
cmd/compile/internal/gc.dowidth(0xc420051d40)
	/home/alberto/go/src/cmd/compile/internal/gc/align.go:186 +0xfb0 fp=0xc440523450 sp=0xc440523318
cmd/compile/internal/types.(*Type).Fields(0xc420051d40, 0x0)
	/home/alberto/go/src/cmd/compile/internal/types/type.go:792 +0x84 fp=0xc440523490 sp=0xc440523450
cmd/compile/internal/types.(*Fields).Len(...)
	/home/alberto/go/src/cmd/compile/internal/types/type.go:1215
cmd/compile/internal/types.(*Type).NumFields(0xc420051d40, 0x0)
	/home/alberto/go/src/cmd/compile/internal/types/type.go:1215 +0x2b fp=0xc4405234b0 sp=0xc440523490
cmd/compile/internal/types.(*Type).IsEmptyInterface(0xc420051d40, 0x0)
	/home/alberto/go/src/cmd/compile/internal/types/type.go:1202 +0x44 fp=0xc4405234d0 sp=0xc4405234b0
cmd/compile/internal/gc.typefmt(0xc420051d40, 0x0, 0x0, 0x1, 0x0, 0x0)
	/home/alberto/go/src/cmd/compile/internal/gc/fmt.go:775 +0x1e79 fp=0xc4405237a0 sp=0xc4405234d0
cmd/compile/internal/gc.tconv(0xc420051d40, 0x0, 0x0, 0x0, 0x0, 0x0)
	/home/alberto/go/src/cmd/compile/internal/gc/fmt.go:1809 +0x7a fp=0xc4405237e0 sp=0xc4405237a0
cmd/compile/internal/gc.typeFormat(0xc420051d40, 0xef87e0, 0xc425525680, 0xc400000076, 0x0)
	/home/alberto/go/src/cmd/compile/internal/gc/fmt.go:1787 +0x92 fp=0xc440523888 sp=0xc4405237e0
cmd/compile/internal/gc.Main.func4(0xc420051d40, 0xef87e0, 0xc425525680, 0xc400000076, 0x0)
	/home/alberto/go/src/cmd/compile/internal/gc/main.go:393 +0x51 fp=0xc4405238c0 sp=0xc440523888
cmd/compile/internal/types.(*Type).Format(0xc420051d40, 0xef87e0, 0xc425525680, 0x76)
	/home/alberto/go/src/cmd/compile/internal/types/utils.go:67 +0x5a fp=0xc4405238f8 sp=0xc4405238c0
fmt.(*pp).handleMethods(0xc425525680, 0xc400000076, 0x1)
	/home/alberto/go/src/fmt/print.go:563 +0x49d fp=0xc440523988 sp=0xc4405238f8
fmt.(*pp).printArg(0xc425525680, 0xb8b9a0, 0xc420051d40, 0x76)
	/home/alberto/go/src/fmt/print.go:679 +0x185 fp=0xc440523a08 sp=0xc440523988
fmt.(*pp).doPrintf(0xc425525680, 0xba0a49, 0x18, 0xc440523d58, 0x1, 0x1)
	/home/alberto/go/src/fmt/print.go:996 +0x169 fp=0xc440523b38 sp=0xc440523a08
fmt.Fprintf(0xef39a0, 0xc42000c018, 0xba0a49, 0x18, 0xc440523d58, 0x1, 0x1, 0x2e, 0x0, 0x0)
	/home/alberto/go/src/fmt/print.go:181 +0x76 fp=0xc440523ba0 sp=0xc440523b38
fmt.Printf(0xba0a49, 0x18, 0xc440523d58, 0x1, 0x1, 0x2e, 0x0, 0x0)
	/home/alberto/go/src/fmt/print.go:190 +0x72 fp=0xc440523c00 sp=0xc440523ba0
cmd/compile/internal/gc.Fatalf(0xba0a49, 0x18, 0xc440523d58, 0x1, 0x1)
	/home/alberto/go/src/cmd/compile/internal/gc/subr.go:170 +0x106 fp=0xc440523c70 sp=0xc440523c00
cmd/compile/internal/gc.dowidth(0xc420051d40)
	/home/alberto/go/src/cmd/compile/internal/gc/align.go:186 +0xfb0 fp=0xc440523da8 sp=0xc440523c70
cmd/compile/internal/types.(*Type).Fields(0xc420051d40, 0x0)
	/home/alberto/go/src/cmd/compile/internal/types/type.go:792 +0x84 fp=0xc440523de8 sp=0xc440523da8
cmd/compile/internal/types.(*Fields).Len(...)
	/home/alberto/go/src/cmd/compile/internal/types/type.go:1215
cmd/compile/internal/types.(*Type).NumFields(0xc420051d40, 0x0)
	/home/alberto/go/src/cmd/compile/internal/types/type.go:1215 +0x2b fp=0xc440523e08 sp=0xc440523de8
cmd/compile/internal/types.(*Type).IsEmptyInterface(0xc420051d40, 0x0)
	/home/alberto/go/src/cmd/compile/internal/types/type.go:1202 +0x44 fp=0xc440523e28 sp=0xc440523e08
cmd/compile/internal/gc.typefmt(0xc420051d40, 0x0, 0x0, 0x1, 0x0, 0x0)
	/home/alberto/go/src/cmd/compile/internal/gc/fmt.go:775 +0x1e79 fp=0xc4405240f8 sp=0xc440523e28
cmd/compile/internal/gc.tconv(0xc420051d40, 0x0, 0x0, 0x0, 0x0, 0x0)
	/home/alberto/go/src/cmd/compile/internal/gc/fmt.go:1809 +0x7a fp=0xc440524138 sp=0xc4405240f8
cmd/compile/internal/gc.typeFormat(0xc420051d40, 0xef87e0, 0xc4255255c0, 0xc400000076, 0x0)
	/home/alberto/go/src/cmd/compile/internal/gc/fmt.go:1787 +0x92 fp=0xc4405241e0 sp=0xc440524138
...additional frames elided...
created by cmd/compile/internal/gc.compileFunctions
	/home/alberto/go/src/cmd/compile/internal/gc/pgen.go:278 +0x10b

goroutine 1 [semacquire]:
sync.runtime_Semacquire(0xc420014d7c)
	/home/alberto/go/src/runtime/sema.go:56 +0x39
sync.(*WaitGroup).Wait(0xc420014d70)
	/home/alberto/go/src/sync/waitgroup.go:131 +0x74
cmd/compile/internal/gc.compileFunctions()
	/home/alberto/go/src/cmd/compile/internal/gc/pgen.go:290 +0x1d3
cmd/compile/internal/gc.Main(0xbb0c68)
	/home/alberto/go/src/cmd/compile/internal/gc/main.go:580 +0x2854
main.main()
	/home/alberto/go/src/cmd/compile/main.go:49 +0x95

[ALTree]

cc @josharian

[mvdan]

internal compiler error while reporting an internal compiler error is the best kind of error.

[josharian]

Nice one. Testing fixes, will be on their way soon.

[gopherbot]

CL https://golang.org/cl/42131 mentions this issue.

[gopherbot]

CL https://golang.org/cl/42130 mentions this issue.