call.c (build_over_call): Make pedwarns about dropped qualifiers into full-fledged errors.

	* call.c (build_over_call): Make pedwarns about dropped qualifiers
	into full-fledged errors.
	* cvt.c (convert_to_reference): Likewise.
	* typeck.c (convert_for_assignment): Likewise.

From-SVN: r22809

8 files changed, 73 insertions, 46 deletions

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index bbb22f67a1c..ba552234ac4 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,5 +1,10 @@
 1998-10-04  Mark Mitchell  <mark@markmitchell.com>
 
+	* call.c (build_over_call): Make pedwarns about dropped qualifiers
+	into full-fledged errors.
+	* cvt.c (convert_to_reference): Likewise.
+	* typeck.c (convert_for_assignment): Likewise.
+
 	* search.c (expand_upcast_vtables): In addition to unsetting 
 	TREE_READONLY, remove top-level const type qualifier.
 
diff --git a/gcc/cp/call.c b/gcc/cp/call.c
index adec61c6014..808c11b4c2e 100644
--- a/gcc/cp/call.c
+++ b/gcc/cp/call.c
@@ -3297,8 +3297,8 @@ build_over_call (cand, args, flags)
 	  char *p = (dv && dc ? "const and volatile"
 		              : dc ? "const" : dv ? "volatile" : "");
 
-	  cp_pedwarn ("passing `%T' as `this' argument of `%#D' discards %s",
-		      TREE_TYPE (argtype), fn, p);
+	  cp_error ("passing `%T' as `this' argument of `%#D' discards %s",
+		    TREE_TYPE (argtype), fn, p);
 	}
       /* [class.mfct.nonstatic]: If a nonstatic member function of a class
 	 X is called for an object that is not of type X, or of a type
diff --git a/gcc/cp/cvt.c b/gcc/cp/cvt.c
index 06c5290c424..f2b41d80b14 100644
--- a/gcc/cp/cvt.c
+++ b/gcc/cp/cvt.c
@@ -450,24 +450,34 @@ convert_to_reference (reftype, expr, convtype, flags, decl)
 	  tree ttl = TREE_TYPE (reftype);
 	  tree ttr = lvalue_type (expr);
 
-	  if (! real_lvalue_p (expr) && ! TYPE_READONLY (ttl))
+	  /* [dcl.init.ref] says that if an rvalue is used to
+	     initialize a reference, then the reference must be to a
+	     non-volatile const type.  */
+	  if (! real_lvalue_p (expr)
+	      && (!TYPE_READONLY (ttl) || TYPE_VOLATILE (ttl)))
 	    {
-	      if (decl)
-		/* Ensure semantics of [dcl.init.ref] */
-		cp_pedwarn ("initialization of non-const reference `%#T' from rvalue `%T'",
-			    reftype, intype);
+	      char* msg;
+
+	      if (TYPE_VOLATILE (ttl) && decl)
+		msg = "initialization of volatile reference type `%#T'";
+	      else if (TYPE_VOLATILE (ttl))
+		msg = "conversion to volatile reference type `%#T'";
+	      else if (decl)
+		msg = "initialization of non-const reference type `%#T'";
 	      else
-		cp_pedwarn ("conversion to non-const `%T' from rvalue `%T'",
-			    reftype, intype);
+		msg = "conversion to non-const reference type `%#T'";
+
+	      cp_error (msg, reftype);
+	      cp_error ("from rvalue of type `%T'", intype);
 	    }
 	  else if (! (convtype & CONV_CONST))
 	    {
 	      if (! TYPE_READONLY (ttl) && TYPE_READONLY (ttr))
-		cp_pedwarn ("conversion from `%T' to `%T' discards const",
-			    ttr, reftype);
+		cp_error ("conversion from `%T' to `%T' discards const",
+			  ttr, reftype);
 	      else if (! TYPE_VOLATILE (ttl) && TYPE_VOLATILE (ttr))
-		cp_pedwarn ("conversion from `%T' to `%T' discards volatile",
-			    ttr, reftype);
+		cp_error ("conversion from `%T' to `%T' discards volatile",
+			  ttr, reftype);
 	    }
 	}
 
diff --git a/gcc/cp/typeck.c b/gcc/cp/typeck.c
index d0be08addad..9e2c1232743 100644
--- a/gcc/cp/typeck.c
+++ b/gcc/cp/typeck.c
@@ -6808,20 +6808,20 @@ convert_for_assignment (type, rhs, errtype, fndecl, parmnum)
 	  if (! TYPE_READONLY (ttl) && TYPE_READONLY (ttr))
 	    {
 	      if (fndecl)
-		cp_pedwarn ("passing `%T' as argument %P of `%D' discards const",
-			    rhstype, parmnum, fndecl);
+		cp_error ("passing `%T' as argument %P of `%D' discards const",
+			  rhstype, parmnum, fndecl);
 	      else
-		cp_pedwarn ("%s to `%T' from `%T' discards const",
-			    errtype, type, rhstype);
+		cp_error ("%s to `%T' from `%T' discards const",
+			  errtype, type, rhstype);
 	    }
 	  if (! TYPE_VOLATILE (ttl) && TYPE_VOLATILE (ttr))
 	    {
 	      if (fndecl)
-		cp_pedwarn ("passing `%T' as argument %P of `%D' discards volatile",
-			    rhstype, parmnum, fndecl);
+		cp_error ("passing `%T' as argument %P of `%D' discards volatile",
+			  rhstype, parmnum, fndecl);
 	      else
-		cp_pedwarn ("%s to `%T' from `%T' discards volatile",
-			    errtype, type, rhstype);
+		cp_error ("%s to `%T' from `%T' discards volatile",
+			  errtype, type, rhstype);
 	    }
 	}
 
@@ -6874,19 +6874,19 @@ convert_for_assignment (type, rhs, errtype, fndecl, parmnum)
 		  if (string_conv_p (type, rhs, 1))
 		    /* converting from string constant to char *, OK.  */;
 		  else if (fndecl)
-		    cp_pedwarn ("passing `%T' as argument %P of `%D' discards const",
-				rhstype, parmnum, fndecl);
+		    cp_error ("passing `%T' as argument %P of `%D' discards const",
+			      rhstype, parmnum, fndecl);
 		  else
-		    cp_pedwarn ("%s to `%T' from `%T' discards const",
+		    cp_error ("%s to `%T' from `%T' discards const",
 				errtype, type, rhstype);
 		}
 	      else if (! TYPE_VOLATILE (ttl) && TYPE_VOLATILE (ttr))
 		{
 		  if (fndecl)
-		    cp_pedwarn ("passing `%T' as argument %P of `%D' discards volatile",
+		    cp_error ("passing `%T' as argument %P of `%D' discards volatile",
 				rhstype, parmnum, fndecl);
 		  else
-		    cp_pedwarn ("%s to `%T' from `%T' discards volatile",
+		    cp_error ("%s to `%T' from `%T' discards volatile",
 				errtype, type, rhstype);
 		}
 	      else if (TREE_CODE (ttl) == TREE_CODE (ttr)
@@ -6948,20 +6948,20 @@ convert_for_assignment (type, rhs, errtype, fndecl, parmnum)
 	      if (const_parity)
 		{
 		  if (fndecl)
-		    cp_pedwarn ("passing `%T' as argument %P of `%D' discards const",
-				rhstype, parmnum, fndecl);
+		    cp_error ("passing `%T' as argument %P of `%D' discards const",
+			      rhstype, parmnum, fndecl);
 		  else
-		    cp_pedwarn ("%s to `%T' from `%T' discards const",
+		    cp_error ("%s to `%T' from `%T' discards const",
 				errtype, type, rhstype);
 		}
 	      if (volatile_parity)
 		{
 		  if (fndecl)
-		    cp_pedwarn ("passing `%T' as argument %P of `%D' discards volatile",
-				rhstype, parmnum, fndecl);
+		    cp_error ("passing `%T' as argument %P of `%D' discards volatile",
+			      rhstype, parmnum, fndecl);
 		  else
-		    cp_pedwarn ("%s to `%T' from `%T' discards volatile",
-				errtype, type, rhstype);
+		    cp_error ("%s to `%T' from `%T' discards volatile",
+			      errtype, type, rhstype);
 		}
 	      if (unsigned_parity > 0)
 		{
diff --git a/gcc/testsuite/g++.old-deja/g++.brendan/crash39.C b/gcc/testsuite/g++.old-deja/g++.brendan/crash39.C
index 67f5538756b..a19187295ec 100644
--- a/gcc/testsuite/g++.old-deja/g++.brendan/crash39.C
+++ b/gcc/testsuite/g++.old-deja/g++.brendan/crash39.C
@@ -29,5 +29,5 @@ public:
 #include <string>
 
 class foo {public: foo () {}};
-class bar {public: bar (foo& dflt);};
+class bar {public: bar (const foo& dflt);};
 class baz: public bar {public: baz (): bar (foo ()) {}};
diff --git a/gcc/testsuite/g++.old-deja/g++.brendan/reference1.C b/gcc/testsuite/g++.old-deja/g++.brendan/reference1.C
index 2a0c2939e4f..84ad6f4bf20 100644
--- a/gcc/testsuite/g++.old-deja/g++.brendan/reference1.C
+++ b/gcc/testsuite/g++.old-deja/g++.brendan/reference1.C
@@ -12,10 +12,10 @@
 extern "C" void printf (char *, ...); 
 
 struct base {
-	int data_member;
+	mutable int data_member;
 
 	base () {}
-	void function_member ();
+	void function_member () const;
 };
 
 base base_object;
@@ -26,7 +26,7 @@ int call_count = 0;
 
 int main ()
 {
-	base& base_ref = base_returning_function ();
+	const base& base_ref = base_returning_function ();
 
 	base_ref.function_member ();
 	base_ref.function_member ();
@@ -48,6 +48,6 @@ base base_returning_function ()
 	return local_base_object;
 }
 
-void base::function_member ()
+void base::function_member () const
 {
 }
diff --git a/gcc/testsuite/g++.old-deja/g++.mike/p785.C b/gcc/testsuite/g++.old-deja/g++.mike/p785.C
index 2188707cade..7d61b093edd 100644
--- a/gcc/testsuite/g++.old-deja/g++.mike/p785.C
+++ b/gcc/testsuite/g++.old-deja/g++.mike/p785.C
@@ -6883,7 +6883,8 @@ and this notice must be preserved on all copies.
 
 typedef void (*GctNameRefProcedure)(GctNameRef&);
 typedef GctNameRef  (*GctNameRefMapper)(GctNameRef&);
-typedef GctNameRef  (*GctNameRefCombiner)(GctNameRef&, GctNameRef&);
+typedef GctNameRef& (*GctNameRefCombiner)(const GctNameRef&, 
+					  const GctNameRef&);
 typedef int  (*GctNameRefPredicate)(GctNameRef&);
 typedef int  (*GctNameRefComparator)(GctNameRef&, GctNameRef&);
 
@@ -6916,11 +6917,11 @@ public:
                         GctNameRefList();
                         GctNameRefList(GctNameRef& head);
                         GctNameRefList(GctNameRef& head, GctNameRefList& tl);
-                        GctNameRefList(GctNameRefList& a);
+                        GctNameRefList(const GctNameRefList& a);
                         GctNameRefList(Pix p);
                         ~GctNameRefList();
 
-  GctNameRefList&              operator = (GctNameRefList& a);
+  GctNameRefList&              operator = (const GctNameRefList& a);
 
   int                   null();
   int                   valid();
@@ -7003,11 +7004,11 @@ inline void dereference(GctNameRefListNode* p)
 }
 
 
-inline GctNameRefListNode* newGctNameRefListNode(GctNameRef& h)
+inline GctNameRefListNode* newGctNameRefListNode(const GctNameRef& h)
 {
   GctNameRefListNode* p = new GctNameRefListNode;
   p->ref = 1;
-  p->hd = h;
+  p->hd = (GctNameRef&) h;
   return p;
 }
 
@@ -7048,9 +7049,10 @@ inline GctNameRefList::GctNameRefList(GctNameRef& head, GctNameRefList& tl)
   reference(P->tl);
 }
 
-inline GctNameRefList::GctNameRefList(GctNameRefList& a)
+inline GctNameRefList::GctNameRefList(const GctNameRefList& a)
 {
-  reference(a.P);
+  GctNameRefList& gl = (GctNameRefList&) a;
+  reference(gl.P);
   P = a.P;
 }
 
@@ -7151,7 +7153,7 @@ public:
 
 static init_NilGctNameRefListNode NilGctNameRefListNode_initializer;
 
-GctNameRefList& GctNameRefList::operator = (GctNameRefList& a)
+GctNameRefList& GctNameRefList::operator = (const GctNameRefList& a)
 {
   reference(a.P);
   dereference(P);
diff --git a/gcc/testsuite/g++.old-deja/g++.other/ref1.C b/gcc/testsuite/g++.old-deja/g++.other/ref1.C
new file mode 100644
index 00000000000..b6d82aa25ca
--- /dev/null
+++ b/gcc/testsuite/g++.old-deja/g++.other/ref1.C
@@ -0,0 +1,10 @@
+// Build don't link:
+
+int f();
+
+void g()
+{
+  const int& i = f(); // OK
+  int& j = f(); // ERROR - initialization of non-const reference 
+  const volatile int& k = f(); // ERROR - initialization of volatile ref
+}