[PATCH 1/2] c++: make cxx_incomplete_type_diagnostic return bool

[PATCH 1/2] c++: make cxx_incomplete_type_diagnostic return bool

[Jason Merrill]

Tested x86_64-pc-linux-gnu, applying to trunk.

-- 8< --

Like other diagnostic functions that might be silenced by options, it should
return whether or not it actually emitted a diagnostic.

gcc/cp/ChangeLog:

	* typeck2.cc (cxx_incomplete_type_diagnostic): Return bool.
	* cp-tree.h (cxx_incomplete_type_diagnostic): Adjust.
---
 gcc/cp/cp-tree.h  |  8 ++++----
 gcc/cp/typeck2.cc | 34 ++++++++++++++++++----------------
 2 files changed, 22 insertions(+), 20 deletions(-)

diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h
index 622752ae4e6..a14eb8d0b9a 100644
--- a/gcc/cp/cp-tree.h
+++ b/gcc/cp/cp-tree.h
@@ -8155,7 +8155,7 @@ extern void maybe_warn_pessimizing_move	     (tree, tree, bool);
 
 /* in typeck2.cc */
 extern void require_complete_eh_spec_types	(tree, tree);
-extern void cxx_incomplete_type_diagnostic	(location_t, const_tree,
+extern bool cxx_incomplete_type_diagnostic	(location_t, const_tree,
 						 const_tree, diagnostic_t);
 inline location_t
 loc_or_input_loc (location_t loc)
@@ -8178,12 +8178,12 @@ cp_expr_loc_or_input_loc (const_tree t)
   return cp_expr_loc_or_loc (t, input_location);
 }
 
-inline void
+inline bool
 cxx_incomplete_type_diagnostic (const_tree value, const_tree type,
 				diagnostic_t diag_kind)
 {
-  cxx_incomplete_type_diagnostic (cp_expr_loc_or_input_loc (value),
-				  value, type, diag_kind);
+  return cxx_incomplete_type_diagnostic (cp_expr_loc_or_input_loc (value),
+					 value, type, diag_kind);
 }
 
 extern void cxx_incomplete_type_error		(location_t, const_tree,
diff --git a/gcc/cp/typeck2.cc b/gcc/cp/typeck2.cc
index c56b69164e2..76a7a7f6b98 100644
--- a/gcc/cp/typeck2.cc
+++ b/gcc/cp/typeck2.cc
@@ -292,7 +292,7 @@ cxx_incomplete_type_inform (const_tree type)
    and TYPE is the type that was invalid.  DIAG_KIND indicates the
    type of diagnostic (see diagnostic.def).  */
 
-void
+bool
 cxx_incomplete_type_diagnostic (location_t loc, const_tree value,
 				const_tree type, diagnostic_t diag_kind)
 {
@@ -304,7 +304,7 @@ cxx_incomplete_type_diagnostic (location_t loc, const_tree value,
 
   /* Avoid duplicate error message.  */
   if (TREE_CODE (type) == ERROR_MARK)
-    return;
+    return false;
 
   if (value)
     {
@@ -336,7 +336,7 @@ cxx_incomplete_type_diagnostic (location_t loc, const_tree value,
       break;
 
     case VOID_TYPE:
-      emit_diagnostic (diag_kind, loc, 0,
+      complained = emit_diagnostic (diag_kind, loc, 0,
 		       "invalid use of %qT", type);
       break;
 
@@ -346,7 +346,7 @@ cxx_incomplete_type_diagnostic (location_t loc, const_tree value,
 	  type = TREE_TYPE (type);
 	  goto retry;
 	}
-      emit_diagnostic (diag_kind, loc, 0,
+      complained = emit_diagnostic (diag_kind, loc, 0,
 		       "invalid use of array with unspecified bounds");
       break;
 
@@ -365,12 +365,12 @@ cxx_incomplete_type_diagnostic (location_t loc, const_tree value,
 	       add a fix-it hint.  */
 	    if (type_num_arguments (TREE_TYPE (member)) == 1)
 	      richloc.add_fixit_insert_after ("()");
-	    emit_diagnostic (diag_kind, &richloc, 0,
+	    complained = emit_diagnostic (diag_kind, &richloc, 0,
 			     "invalid use of member function %qD "
 			     "(did you forget the %<()%> ?)", member);
 	  }
 	else
-	  emit_diagnostic (diag_kind, loc, 0,
+	  complained = emit_diagnostic (diag_kind, loc, 0,
 			   "invalid use of member %qD "
 			   "(did you forget the %<&%> ?)", member);
       }
@@ -380,38 +380,38 @@ cxx_incomplete_type_diagnostic (location_t loc, const_tree value,
       if (is_auto (type))
 	{
 	  if (CLASS_PLACEHOLDER_TEMPLATE (type))
-	    emit_diagnostic (diag_kind, loc, 0,
+	    complained = emit_diagnostic (diag_kind, loc, 0,
 			     "invalid use of placeholder %qT", type);
 	  else
-	    emit_diagnostic (diag_kind, loc, 0,
+	    complained = emit_diagnostic (diag_kind, loc, 0,
 			     "invalid use of %qT", type);
 	}
       else
-	emit_diagnostic (diag_kind, loc, 0,
+	complained = emit_diagnostic (diag_kind, loc, 0,
 			 "invalid use of template type parameter %qT", type);
       break;
 
     case BOUND_TEMPLATE_TEMPLATE_PARM:
-      emit_diagnostic (diag_kind, loc, 0,
+      complained = emit_diagnostic (diag_kind, loc, 0,
 		       "invalid use of template template parameter %qT",
 		       TYPE_NAME (type));
       break;
 
     case TYPE_PACK_EXPANSION:
-      emit_diagnostic (diag_kind, loc, 0,
+      complained = emit_diagnostic (diag_kind, loc, 0,
 		       "invalid use of pack expansion %qT", type);
       break;
 
     case TYPENAME_TYPE:
     case DECLTYPE_TYPE:
-      emit_diagnostic (diag_kind, loc, 0,
+      complained = emit_diagnostic (diag_kind, loc, 0,
 		       "invalid use of dependent type %qT", type);
       break;
 
     case LANG_TYPE:
       if (type == init_list_type_node)
 	{
-	  emit_diagnostic (diag_kind, loc, 0,
+	  complained = emit_diagnostic (diag_kind, loc, 0,
 			   "invalid use of brace-enclosed initializer list");
 	  break;
 	}
@@ -419,20 +419,22 @@ cxx_incomplete_type_diagnostic (location_t loc, const_tree value,
       if (value && TREE_CODE (value) == COMPONENT_REF)
 	goto bad_member;
       else if (value && TREE_CODE (value) == ADDR_EXPR)
-	emit_diagnostic (diag_kind, loc, 0,
+	complained = emit_diagnostic (diag_kind, loc, 0,
 			 "address of overloaded function with no contextual "
 			 "type information");
       else if (value && TREE_CODE (value) == OVERLOAD)
-	emit_diagnostic (diag_kind, loc, 0,
+	complained = emit_diagnostic (diag_kind, loc, 0,
 			 "overloaded function with no contextual type information");
       else
-	emit_diagnostic (diag_kind, loc, 0,
+	complained = emit_diagnostic (diag_kind, loc, 0,
 			 "insufficient contextual information to determine type");
       break;
 
     default:
       gcc_unreachable ();
     }
+
+  return complained;
 }
 
 /* Print an error message for invalid use of an incomplete type.

base-commit: 66c7257b675068fe62505d74873371fd0508b499
-- 
2.31.1

[PATCH 2/2] c++: make trait of incomplete type a permerror [PR109277]

[Jason Merrill]

Tested x86_64-pc-linux-gnu, applying to trunk.

-- 8< --

An incomplete type argument to several traits is specified to be undefined
behavior in the library; since it's a compile-time property, we diagnose
it.  But apparently some code was relying on the previous behavior of not
diagnosing.  So let's make it a permerror.

The assert in cxx_incomplete_type_diagnostic didn't like that, and I don't
see the point of having the assert, so let's just remove it.

	PR c++/109277

gcc/cp/ChangeLog:

	* semantics.cc (check_trait_type): Handle incomplete type directly.
	* typeck2.cc (cxx_incomplete_type_diagnostic): Remove assert.

gcc/testsuite/ChangeLog:

	* g++.dg/ext/is_convertible5.C: New test.
---
 gcc/cp/semantics.cc                        | 7 ++++++-
 gcc/cp/typeck2.cc                          | 4 ----
 gcc/testsuite/g++.dg/ext/is_convertible5.C | 7 +++++++
 3 files changed, 13 insertions(+), 5 deletions(-)
 create mode 100644 gcc/testsuite/g++.dg/ext/is_convertible5.C

diff --git a/gcc/cp/semantics.cc b/gcc/cp/semantics.cc
index 99a76e3ed65..45e0b0e81d3 100644
--- a/gcc/cp/semantics.cc
+++ b/gcc/cp/semantics.cc
@@ -12107,7 +12107,12 @@ check_trait_type (tree type, int kind = 1)
   if (VOID_TYPE_P (type))
     return true;
 
-  return !!complete_type_or_else (strip_array_types (type), NULL_TREE);
+  type = complete_type (strip_array_types (type));
+  if (!COMPLETE_TYPE_P (type)
+      && cxx_incomplete_type_diagnostic (NULL_TREE, type, DK_PERMERROR)
+      && !flag_permissive)
+    return false;
+  return true;
 }
 
 /* Process a trait expression.  */
diff --git a/gcc/cp/typeck2.cc b/gcc/cp/typeck2.cc
index 76a7a7f6b98..bf03967a71f 100644
--- a/gcc/cp/typeck2.cc
+++ b/gcc/cp/typeck2.cc
@@ -298,10 +298,6 @@ cxx_incomplete_type_diagnostic (location_t loc, const_tree value,
 {
   bool is_decl = false, complained = false;
 
-  gcc_assert (diag_kind == DK_WARNING 
-	      || diag_kind == DK_PEDWARN 
-	      || diag_kind == DK_ERROR);
-
   /* Avoid duplicate error message.  */
   if (TREE_CODE (type) == ERROR_MARK)
     return false;
diff --git a/gcc/testsuite/g++.dg/ext/is_convertible5.C b/gcc/testsuite/g++.dg/ext/is_convertible5.C
new file mode 100644
index 00000000000..ab9be05afea
--- /dev/null
+++ b/gcc/testsuite/g++.dg/ext/is_convertible5.C
@@ -0,0 +1,7 @@
+// PR c++/109277
+// { dg-do compile { target c++11 } }
+// { dg-options -fpermissive }
+
+struct a;
+struct b{};
+static_assert (!__is_convertible (a, b), ""); // { dg-warning "incomplete" }
-- 
2.31.1