gccgo: internal compiler error for interface with cyclic result types #25851
Description
With
gccgo (google-gccgo-261288) 9.0.0 20180607 (experimental) Copyright (C) 2018 Free Software Foundation, Inc. This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. the following program
$ cat x.go package main func main() { } type I interface { M1() interface { I } M2() interface { I } } type S struct{} func (S) M1() interface{ I } { return nil } func (S) M2() interface{ I } { return nil }crashes the compiler:
$ gccgo x.go gccgo: internal compiler error: Segmentation fault signal terminated program go1 Please submit a full bug report, with preprocessed source if appropriate. See <http://go.ext.google.com/go/> for instructions. The program compiles (somewhat surprisingly) without error if the struct definition is absent:
$ cat x.go package main func main() { } type I interface { M1() interface { I } M2() interface { I } }For the reference:
- go/types accepts this code (not clear that it should)
- cmd/compile doesn't terminate (issue cmd/compile: recursive embedded interface types cause stack overflow #25262)
cc: @thanm