Go patch committed: Use package path with embedded builtin

[Ian Lance Taylor via Gcc-patches]

This patch to the Go frontend changes the mangled name of a struct to
use the package path with an embedded builtin type.  The test case is
https://go.dev/cl/414235.  This fixes https://go.dev/issue/52856.
Bootstrapped and ran Go testsuite on x86_64-pc-linux-gnu.  Committed
to mainline.

Ian

74956337e8276e5bc9524104b01c147374dd94e7
diff --git a/gcc/go/gofrontend/MERGE b/gcc/go/gofrontend/MERGE
index 551ea650acf..13cb6ea4046 100644
--- a/gcc/go/gofrontend/MERGE
+++ b/gcc/go/gofrontend/MERGE
@@ -1,4 +1,4 @@
-d5b4abed2f206e492890acc20738e89617ea542c
+c7238f58a26131b7611eff6f555cab02af8a623c
 
 The first line of this file holds the git revision number of the last
 merge done from the gofrontend repository.
diff --git a/gcc/go/gofrontend/names.cc b/gcc/go/gofrontend/names.cc
index f85d84ceadf..dac7f20f5c1 100644
--- a/gcc/go/gofrontend/names.cc
+++ b/gcc/go/gofrontend/names.cc
@@ -831,15 +831,28 @@ Struct_type::do_mangled_name(Gogo* gogo, std::string* ret,
              ret->push_back(' ');
            }
 
-         // For an anonymous field with an alias type, the field name
-         // is the alias name.
-         if (p->is_anonymous()
-             && p->type()->named_type() != NULL
-             && p->type()->named_type()->is_alias())
-           p->type()->named_type()->append_symbol_type_name(gogo, true, ret,
-                                                            is_non_identifier);
+         const Type* ft = p->type();
+         const Named_type* nt = ft->named_type();
+
+         if (p->is_anonymous() && nt != NULL && nt->is_builtin())
+           {
+             // For an embedded field with a builtin type, we must
+             // include a package path.  Otherwise embedding builtin
+             // types in different packages will produce identical
+             // types, which shouldn't happen because the builtin
+             // types are not exported.
+             ret->append(gogo->pkgpath());
+             ret->push_back('.');
+             nt->append_symbol_type_name(gogo, true, ret, is_non_identifier);
+           }
+         else if (p->is_anonymous() && nt != NULL && nt->is_alias())
+           {
+             // For an anonymous field with an alias type, the field name
+             // is the alias name.
+             nt->append_symbol_type_name(gogo, true, ret, is_non_identifier);
+           }
          else
-           this->append_mangled_name(p->type(), gogo, ret, is_non_identifier);
+           this->append_mangled_name(ft, gogo, ret, is_non_identifier);
 
          if (p->has_tag())
            {