What version of Go are you using (go version)?

$ go version
go version go1.12.2 gccgo (GCC) 10.0.0 20190624 (experimental) linux/amd64

Does this issue reproduce with the latest release?

Yes.

What operating system and processor architecture are you using (go env)?

$ go env
GOARCH="amd64"
GOBIN=""
GOCACHE="/usr/local/google/home/thanm/.cache/go-build"
GOEXE=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOOS="linux"
GOPROXY=""
GORACE=""
GOTMPDIR=""
CC="gcc"
CXX="g++"
CGO_ENABLED="1"
GOMOD=""
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-fPIC -m64 -pthread -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build416581980=/tmp/go-build -gno-record-gcc-switches -funwind-tables"

What did you do?

Compile these two packages, first "pf" and the "upf". Source code:

Package "pf":

`package pf

import (
"regexp"
"strings"
)

var (
regexName = regexp.MustCompile(^[_a-zA-Z][_a-zA-Z0-9]*$)
regexFullName = regexp.MustCompile(^[_a-zA-Z][_a-zA-Z0-9]*(\.[_a-zA-Z][_a-zA-Z0-9]*)*$)
)

type Name string

func (n Name) IsValid() bool {
return regexName.MatchString(string(n))
}

type FullName string

func (n FullName) IsValid() bool {
return regexFullName.MatchString(string(n))
}

func (n FullName) Name() Name {
if i := strings.LastIndexByte(string(n), '.'); i >= 0 {
return Name(n[i+1:])
}
return Name(n)
}
`
Package "upf"

`package upf

import "pf"

var n pf.Name

func Expo(fn pf.FullName) pf.Name {
return fn.Name()
}
`

What did you expect to see?

Clean build

What did you see instead?

Assert with this stack trace:

go1: internal compiler error: in package_index, at go/gofrontend/export.cc:1143 0x6af1bb Export::package_index(Package const*) const ../../gcc-trunk/gcc/go/gofrontend/export.cc:1143 0x6beeb8 Export_function_body::package_index(Package const*) const ../../gcc-trunk/gcc/go/gofrontend/export.h:368 0x6beeb8 Expression::export_name(Export_function_body*, Named_object const*) ../../gcc-trunk/gcc/go/gofrontend/expressions.cc:98 0x6ca108 Expression::export_expression(Export_function_body*) const ../../gcc-trunk/gcc/go/gofrontend/expressions.h:1054 0x6ca108 Call_expression::do_export(Export_function_body*) const ../../gcc-trunk/gcc/go/gofrontend/expressions.cc:12226 0x7481c2 Expression::export_expression(Export_function_body*) const ../../gcc-trunk/gcc/go/gofrontend/expressions.h:1054 0x7481c2 Variable_declaration_statement::do_export_statement(Export_function_body*) ../../gcc-trunk/gcc/go/gofrontend/statements.cc:447 0x6fe68b Statement::export_statement(Export_function_body*) ../../gcc-trunk/gcc/go/gofrontend/statements.h:339 0x6fe68b Block::export_block(Export_function_body*) ../../gcc-trunk/gcc/go/gofrontend/gogo.cc:6852 0x74c0e1 Block_statement::export_block(Export_function_body*, Block*, bool) ../../gcc-trunk/gcc/go/gofrontend/statements.cc:2143 0x6fe68b Statement::export_statement(Export_function_body*) ../../gcc-trunk/gcc/go/gofrontend/statements.h:339 0x6fe68b Block::export_block(Export_function_body*) ../../gcc-trunk/gcc/go/gofrontend/gogo.cc:6852 0x6fee14 Function::export_func_with_type(Export*, Named_object const*, Function_type const*, std::vector<Named_object*, std::allocator<Named_object*> >*, bool, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, Block*, Location) ../../gcc-trunk/gcc/go/gofrontend/gogo.cc:5914 0x6ff568 Function::export_func(Export*, Named_object const*) const ../../gcc-trunk/gcc/go/gofrontend/gogo.cc:5768 0x704243 Named_object::export_named_object(Export*) const ../../gcc-trunk/gcc/go/gofrontend/gogo.cc:8493 0x75815a Named_type::do_export(Export*) const ../../gcc-trunk/gcc/go/gofrontend/types.cc:11120 0x6ae957 Type::export_type(Export*) const ../../gcc-trunk/gcc/go/gofrontend/types.h:1076 0x6ae957 Export::write_type_definition(Type const*, int) ../../gcc-trunk/gcc/go/gofrontend/export.cc:1097 0x6aec27 Export::write_types(int) ../../gcc-trunk/gcc/go/gofrontend/export.cc:1034 0x6b32f3 Export::export_globals(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, std::map<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, Package*, std::less<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::allocator<std::pair<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const, Package*> > > const&, std::map<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, Package*, std::less<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::allocator<std::pair<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const, Package*> > > const&, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, Import_init_set const&, Bindings const*) ../../gcc-trunk/gcc/go/gofrontend/export.cc:368
Looks at first blush like a problem with building the package index.