@randall77 @dr2chase @mdempsky

Closing on the assumption that this is a dup of #52590. Thanks for reporting it.

@ianlancetaylor This is different bug involve initialization of composite literal.

Yeah, #52590 was an exporter issue, but this issue is reproducible with a single source file (i.e., no export involved).

Ah, sorry.

FWIW, the issue repros in Go 1.17 too, after removing generics: https://go.dev/play/p/3iLxskmJgIS?v=goprev

Edit: Simpler: https://go.dev/play/p/UU1h7nOwoyY?v=goprev

@mdempsky Seems the bug was introduced when the compiler was changed to handle array literal with more than 4 elements. This program:

package p

type b bool

func f() {
	func() [10][]bool {
		return [10][]bool{
			[]bool{bool(g(false) < "")},
			[]bool{}, []bool{}, []bool{}, []bool{}}
	}()
}

func g(b) (s string) { return }

compile ok with go1.4 😃

@cuonglm Thanks. Do you want to take this issue?

@cuonglm Thanks. Do you want to take this issue?

Yes, no problem!

@mdempsky So for code like:

package p

func f() {
	var x string
	func() [10][]bool {
		return [10][]bool{
			[]bool{bool(x < "")},
			[]bool{}, []bool{}, []bool{}, []bool{}}
	}()
}

We initialize the code roughly as:

.stmp_1[0] = len(x) < 0
~R0 = .stmp_0

Then call to fixedlit at L573 (cmd/compile/internal/walk/complit.go) rewrites it to:

.stmp_1[0] = .autotmp_4 < 0
~R0 = .stmp_0
autotmp_3 = <nil>
autotmp_2 = &.autotmp_3
.autotmp_4 = len(x)
.autotmp_2[0] = .autotmp_4 < 0
<node VARKILL>

I have no ideal how to fix it yet.

@cuonglm Okay, I can take a look tomorrow. Thanks for investigating!

@cuonglm Okay, I can take a look tomorrow. Thanks for investigating!

Don't mind, I think I figured it out!

Change https://go.dev/cl/403995 mentions this issue: cmd/compile: fix static init of literal contains dynamic exprs

@dmitshur did we want to push for a backport for this one, or does it not make the train for next week?

This isn't a Go 1.18 regression. I don't think it needs to be backported.

Generally ICEs that are triggered only by fuzzing the compiler don't need backporting.
If it generated bad code, then maybe.