re PR c++/57942 (g++-4.8.1 tries to instantiate wrong constructor)

/cp
2013-07-24  Paolo Carlini  <paolo.carlini@oracle.com>

	PR c++/57942
	* typeck.c (ptr_reasonably_similar): Use COMPARE_STRICT if one of
	the target types is incomplete; return a bool, not an int.
	* cp-tree.h (ptr_reasonably_similar): Adjust declaration.

/testsuite
2013-07-24  Paolo Carlini  <paolo.carlini@oracle.com>

	PR c++/57942
	* g++.dg/inherit/pr57942.C: New.

From-SVN: r201201

5 files changed, 35 insertions, 9 deletions

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 862e859..f7052cb 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,10 @@
+2013-07-24  Paolo Carlini  <paolo.carlini@oracle.com>
+
+	PR c++/57942
+	* typeck.c (ptr_reasonably_similar): Use COMPARE_STRICT if one of
+	the target types is incomplete; return a bool, not an int.
+	* cp-tree.h (ptr_reasonably_similar): Adjust declaration.
+
 2013-07-22  Paolo Carlini  <paolo.carlini@oracle.com>
 
 	* cp-tree.h (DERIVED_FROM_P): Pass tf_none to lookup_base, not
diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h
index 459c0e2..4a2271f 100644
--- a/gcc/cp/cp-tree.h
+++ b/gcc/cp/cp-tree.h
@@ -6022,7 +6022,7 @@ extern tree convert_for_initialization		(tree, tree, tree, int,
 extern int comp_ptr_ttypes			(tree, tree);
 extern bool comp_ptr_ttypes_const		(tree, tree);
 extern bool error_type_p			(const_tree);
-extern int ptr_reasonably_similar		(const_tree, const_tree);
+extern bool ptr_reasonably_similar		(const_tree, const_tree);
 extern tree build_ptrmemfunc			(tree, tree, int, bool,
 						 tsubst_flags_t);
 extern int cp_type_quals			(const_tree);
diff --git a/gcc/cp/typeck.c b/gcc/cp/typeck.c
index ef781a3..6f33055 100644
--- a/gcc/cp/typeck.c
+++ b/gcc/cp/typeck.c
@@ -8599,10 +8599,10 @@ error_type_p (const_tree type)
     }
 }
 
-/* Returns 1 if to and from are (possibly multi-level) pointers to the same
+/* Returns true if to and from are (possibly multi-level) pointers to the same
    type or inheritance-related types, regardless of cv-quals.  */
 
-int
+bool
 ptr_reasonably_similar (const_tree to, const_tree from)
 {
   for (; ; to = TREE_TYPE (to), from = TREE_TYPE (from))
@@ -8614,7 +8614,7 @@ ptr_reasonably_similar (const_tree to, const_tree from)
 	return !error_type_p (to);
 
       if (TREE_CODE (to) != TREE_CODE (from))
-	return 0;
+	return false;
 
       if (TREE_CODE (from) == OFFSET_TYPE
 	  && comptypes (TYPE_OFFSET_BASETYPE (to),
@@ -8624,19 +8624,24 @@ ptr_reasonably_similar (const_tree to, const_tree from)
 
       if (TREE_CODE (to) == VECTOR_TYPE
 	  && vector_types_convertible_p (to, from, false))
-	return 1;
+	return true;
 
       if (TREE_CODE (to) == INTEGER_TYPE
 	  && TYPE_PRECISION (to) == TYPE_PRECISION (from))
-	return 1;
+	return true;
 
       if (TREE_CODE (to) == FUNCTION_TYPE)
 	return !error_type_p (to) && !error_type_p (from);
 
       if (!TYPE_PTR_P (to))
-	return comptypes
-	  (TYPE_MAIN_VARIANT (to), TYPE_MAIN_VARIANT (from),
-	   COMPARE_BASE | COMPARE_DERIVED);
+	{
+	  /* When either type is incomplete avoid DERIVED_FROM_P,
+	     which may call complete_type (c++/57942).  */
+	  bool b = !COMPLETE_TYPE_P (to) || !COMPLETE_TYPE_P (from);
+	  return comptypes
+	    (TYPE_MAIN_VARIANT (to), TYPE_MAIN_VARIANT (from),
+	     b ? COMPARE_STRICT : COMPARE_BASE | COMPARE_DERIVED);
+	}
     }
 }
 
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 7b24942e..1cfb5a4 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2013-07-24  Paolo Carlini  <paolo.carlini@oracle.com>
+
+	PR c++/57942
+	* g++.dg/inherit/pr57942.C: New.
+
 2013-07-23  Michael Meissner  <meissner@linux.vnet.ibm.com>
 
 	* gcc.target/powerpc/bool2.h: New file, test the code generation
diff --git a/gcc/testsuite/g++.dg/inherit/pr57942.C b/gcc/testsuite/g++.dg/inherit/pr57942.C
new file mode 100644
index 0000000..580e9ec
--- /dev/null
+++ b/gcc/testsuite/g++.dg/inherit/pr57942.C
@@ -0,0 +1,9 @@
+// PR c++/57942
+
+template<typename T> struct S { typename T::error type; };
+struct X {};
+void f(S<int>*);
+void f(...);
+void g() { f((X*)0); }
+struct Y;
+void h() { f((Y*)0); }