On Wed, Feb 13, 2019 at 11:44:42AM -0500, Jason Merrill wrote:
> On 2/13/19 12:13 AM, Marek Polacek wrote:
> > Here we ICE because we're in a template and the constructor contains an
> > OVERLOAD, so calling check_narrowing -> maybe_constant_value crashes.
> > 
> > check_narrowing deliberately calls maybe_constant_value and not
> > fold_non_dependent_expr so as to avoid instantiating expressions twice.
> > 
> > So let's use instantiate_non_dependent_expr_sfinae to deal with the 
> > OVERLOAD;
> > fold_non_dependent_expr always calls maybe_constant_value and we can avoid
> > that call.
> > 
> > Bootstrapped/regtested on x86_64-linux, ok for trunk?
> > 
> > 2019-02-12  Marek Polacek  <pola...@redhat.com>
> > 
> >     PR c++/89297 - ICE with OVERLOAD in template.
> >     * semantics.c (finish_compound_literal): Call
> >     instantiate_non_dependent_expr_sfinae.
> > 
> >     * g++.dg/cpp0x/initlist113.C: New test.
> > 
> > diff --git gcc/cp/semantics.c gcc/cp/semantics.c
> > index 786f18ab0c8..e89a38d3cba 100644
> > --- gcc/cp/semantics.c
> > +++ gcc/cp/semantics.c
> > @@ -2826,9 +2826,13 @@ finish_compound_literal (tree type, tree 
> > compound_literal,
> >       return error_mark_node;
> >     compound_literal = reshape_init (type, compound_literal, complain);
> >     if (SCALAR_TYPE_P (type)
> > -      && !BRACE_ENCLOSED_INITIALIZER_P (compound_literal)
> > -      && !check_narrowing (type, compound_literal, complain))
> > -    return error_mark_node;
> > +      && !BRACE_ENCLOSED_INITIALIZER_P (compound_literal))
> > +    {
> > +      compound_literal
> > +   = instantiate_non_dependent_expr_sfinae (compound_literal, complain);
> > +      if (!check_narrowing (type, compound_literal, complain))
> > +   return error_mark_node;
> > +    }
> 
> Since you change 'compound_literal', this seems to mean we will end up
> returning a constructor containing instantiated trees later instantiation
> isn't prepared to handle.

Interesting, I don't recall seeing that, and it certainly regtested fine.  So
then we could instantiate the complit just for the check_narrowing purposes
and proceed as before?

2019-02-13  Marek Polacek  <pola...@redhat.com>

        PR c++/89297 - ICE with OVERLOAD in template.
        * semantics.c (finish_compound_literal): Call
        instantiate_non_dependent_expr_sfinae.

        * g++.dg/cpp0x/initlist113.C: New test.

diff --git gcc/cp/semantics.c gcc/cp/semantics.c
index 786f18ab0c8..79f07f3a264 100644
--- gcc/cp/semantics.c
+++ gcc/cp/semantics.c
@@ -2826,9 +2826,13 @@ finish_compound_literal (tree type, tree 
compound_literal,
     return error_mark_node;
   compound_literal = reshape_init (type, compound_literal, complain);
   if (SCALAR_TYPE_P (type)
-      && !BRACE_ENCLOSED_INITIALIZER_P (compound_literal)
-      && !check_narrowing (type, compound_literal, complain))
-    return error_mark_node;
+      && !BRACE_ENCLOSED_INITIALIZER_P (compound_literal))
+    {
+      tree t = instantiate_non_dependent_expr_sfinae (compound_literal,
+                                                     complain);
+      if (!check_narrowing (type, t, complain))
+       return error_mark_node;
+    }
   if (TREE_CODE (type) == ARRAY_TYPE
       && TYPE_DOMAIN (type) == NULL_TREE)
     {
diff --git gcc/testsuite/g++.dg/cpp0x/initlist113.C 
gcc/testsuite/g++.dg/cpp0x/initlist113.C
new file mode 100644
index 00000000000..0b7e7ff606a
--- /dev/null
+++ gcc/testsuite/g++.dg/cpp0x/initlist113.C
@@ -0,0 +1,11 @@
+// PR c++/89297
+// { dg-do compile { target c++11 } }
+
+int id(int v) { return v; }
+float id(float v) { return v; }
+
+template <typename>
+int foo(int v)
+{
+    return int{id(v)};
+}

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