cmd/compile: do not report internal compiler error after ordinary compiler error

[rsc]

For #21882, instead of checking in the actual fix, I'd like to just silence any "internal compiler error" that happens after a regular compiler error has already been printed. The old C version of the compiler did this and it was quite effective. This change would be very low risk, in contrast to trying to fix actual errors.

[mdempsky]

Currently, we have code in Fatalf to only print stack traces for dev builds, and to instead just print a message asking users to file a bug report for release builds.

Is the issue that behavior isn't working as intended, or that you don't think we should even do that if we've printed an actual error first?

[mdempsky]

Yeah, looks like that code is broken.

[mdempsky]

Changing Fatalf to check for "go" instead of "release" changes #21882 to print:

/tmp/q.go:3:6: invalid recursive type N
/tmp/q.go:3:6: internal compiler error: invalid alignment for N

Please file a bug report including a short program that triggers the error.
https://golang.org/issue/new

Is that desirable, or do you prefer we squelch the error altogether since there was a proper error?

[rsc]

Please silence the whole thing. If there was already an error reported and then the compiler shoots itself in the foot, better to just let the user fix the reported error and try again. If no error was reported yet, then of course print the internal error.

This logic was invaluable when Dmitriy was fuzzing the compiler. It just eliminates a whole class of mostly useless bug reports. :-)

[gopherbot]

Change https://golang.org/cl/70850 mentions this issue: cmd/compile: omit ICE diagnostics after normal error messages

[mdempsky]

Reopening for Go 1.9.x.

[rsc]

CL 22252 OK for Go 1.9.2. (not the right number)
CL 70850 OK for Go 1.9.2.

[gopherbot]

Change https://golang.org/cl/70985 mentions this issue: [release-branch.go1.9] cmd/compile: omit ICE diagnostics after normal error messages

[rsc]

go1.9.2 has been packaged and includes:

• CL 70850

The release is posted at golang.org/dl.

— golang.org/x/build/cmd/releasebot, Oct 26 21:09:22 UTC