[PR C++/83287] Mark lookup for keeping

https://gcc.gnu.org/ml/gcc-patches/2017-12/msg00242.html
	PR c++/83287
	* tree.c (build_min): Check CAST_EXPR arg for OVERLOADs.

	* g++.dg/lookup/pr83287.C: New.

From-SVN: r255429

gcc/cp/ChangeLog

+2017-12-05  Nathan Sidwell  <nathan@acm.org>
+
+	PR c++/83287
+	* tree.c (build_min): Check CAST_EXPR arg for OVERLOADs.
+
 2017-12-05  Martin Liska  <mliska@suse.cz>
 	    Jakub Jelinek  <jakub@redhat.com>
 

gcc/cp/tree.c

@@ -3230,6 +3230,13 @@ build_min (enum tree_code code, tree tt, ...)
     }
 
   va_end (p);
+
+  if (code == CAST_EXPR)
+    /* The single operand is a TREE_LIST, which we have to check.  */
+    for (tree v = TREE_OPERAND (t, 0); v; v = TREE_CHAIN (v))
+      if (TREE_CODE (TREE_VALUE (v)) == OVERLOAD)
+	lookup_keep (TREE_VALUE (v), true);
+
   return t;
 }
 

gcc/testsuite/ChangeLog

+2017-12-05  Nathan Sidwell  <nathan@acm.org>
+
+	PR c++/83287
+	* g++.dg/lookup/pr83287.C: New.
+
 2017-12-05  Jakub Jelinek  <jakub@redhat.com>
 
 	PR testsuite/83289

gcc/testsuite/g++.dg/lookup/pr83287.C

+// PR c++/83287 failed to keep lookup until instantiation time
+
+void foo ();
+
+namespace {
+  void foo (int);
+}
+
+template <class T>
+void bar ()
+{
+  T (*p)() = (T (*)(void)) foo;
+}
+
+void
+baz ()
+{
+  bar<void> ();
+}