[PR c++/84492] stmt expr ending with overload

We ICEd when returning a stmt expr that ends with an overloaded
function, because instantiate_type did not know what to do with
STMT_EXPRs.  And it shouldn't have to: the expected type of a stmt
expr cannot be used to resolve its value: an unresolved overload
cannot supply the result of a stmt expr.  Catch that and report the
error in the stmt expr before we have a chance to instantiate it.

for  gcc/cp/ChangeLog

	PR c++/84492
	* semantics.c (finish_stmt_expr_expr): Reject unresolved
	overloads used as stmt expr values.

for  gcc/testsuite/ChangeLog

	PR c++/84492
	* g++.dg/pr84492.C: New.

From-SVN: r258269

gcc/cp/ChangeLog

@@ -1,3 +1,9 @@
+2018-03-06  Alexandre Oliva <aoliva@redhat.com>
+
+	PR c++/84492
+	* semantics.c (finish_stmt_expr_expr): Reject unresolved
+	overloads used as stmt expr values.
+
 2018-03-05  Jason Merrill  <jason@redhat.com>
 
 	PR c++/84708 - ICE with lambda in local class NSDMI.

gcc/cp/semantics.c

@@ -2114,7 +2114,14 @@ finish_stmt_expr_expr (tree expr, tree stmt_expr)
     {
       tree type = TREE_TYPE (expr);
 
-      if (processing_template_decl)
+      if (type && type_unknown_p (type))
+	{
+	  error ("a statement expression is an insufficient context"
+		 " for overload resolution");
+	  TREE_TYPE (stmt_expr) = error_mark_node;
+	  return error_mark_node;
+	}
+      else if (processing_template_decl)
 	{
 	  expr = build_stmt (input_location, EXPR_STMT, expr);
 	  expr = add_stmt (expr);

gcc/testsuite/ChangeLog

@@ -1,3 +1,8 @@
+2018-03-06  Alexandre Oliva <aoliva@redhat.com>
+
+	PR c++/84492
+	* g++.dg/pr84492.C: New.
+
 2018-03-05  Bill Schmidt  <wschmidt@linux.vnet.ibm.com>
 
 	* gcc.target/powerpc/spec-barr-1.c: Change called function name to

gcc/testsuite/g++.dg/pr84492.C

@@ -0,0 +1,40 @@
+// { dg-do compile }
+// { dg-options "-fpermissive" }
+
+template<int> int foo()
+{
+  return ({ foo; }); // { dg-error "insufficient context" }
+}
+
+int bar()
+{
+  return ({ foo; }); // { dg-error "insufficient context" }
+}
+
+void bar(int);
+
+typedef void (*bart)(int);
+
+bart barf()
+{
+  return ({ bar; }); // { dg-error "insufficient context" }
+}
+
+bool bark()
+{
+  return ({ barf; }); // ok, no overload
+}
+
+template <typename T>
+class C
+{
+  static int f();
+  bool g()
+  {
+    return ({ f; }); // ok, no overload
+  }
+  bool g(int)
+  {
+    return ({ g; }); // { dg-error "insufficient context" }
+  }
+};