go version go1.4 darwin/amd64

This:

type foo struct {
    bar foo
}

produces the expected error message:

invalid recursive type foo

But if more than one recursive reference is present:

type foo struct {
    bar foo
    blah foo
}

then it crashes, rather than reporting the error as expected:

/usr/local/go/pkg/tool/darwin_amd64/6g: signal: segmentation fault