[C++ Patch] Three additional bitfield diagnostic tweaks (a regression fix included)

[Paolo Carlini <paolo.carlini@oracle.com>]

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Hi,

I'm bundling together 3 more. In attachment order:

1- Since we decided to explicitly print the wrong type, I suppose we 
want to consistently do that in templates too.

2- Unfortunately I have to fix another buglet I recently introduced, 
completely similar to c++/88222 fixed by Marek. Well, at least we will 
not print anymore an empty '' when the unqualified_id is null because 
the field is unnamed.

3- In the non-static case too, when from grokdeclarator we are calling 
FIELD_DECL and passing the location as first argument, I think we want 
to likewise pass declarator->id_loc when available.

The added/extended testcase exercise all of the above. Tested x86_64-linux.

Thanks, Paolo.

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/cp
2018-12-06  Paolo Carlini  <paolo.carlini@oracle.com>

	* class.c (check_bitfield_decl): In error message about non-integral
	type print the type itself too.
	* decl.c (grokdeclarator): Do not ICE on unnamed bit-fields declared
	friends; when calling build_decl for a FIELD_DECL possibly pass the
	declarator->id_loc.

/testsuite
2018-12-06  Paolo Carlini  <paolo.carlini@oracle.com>

	* g++.dg/parse/bitfield7.C: New.
	* g++.dg/other/bitfield2.C: Check location and type.
	* g++.dg/parse/bitfield1.C: Likewise.
	* g++.dg/parse/bitfield2.C: Likewise.

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Index: cp/class.c
===================================================================
--- cp/class.c	(revision 266840)
+++ cp/class.c	(working copy)
@@ -3218,7 +3218,8 @@ check_bitfield_decl (tree field)
   /* Detect invalid bit-field type.  */
   if (!INTEGRAL_OR_ENUMERATION_TYPE_P (type))
     {
-      error ("bit-field %q+#D with non-integral type", field);
+      error_at (DECL_SOURCE_LOCATION (field),
+		"bit-field %q#D with non-integral type %qT", field, type);
       w = error_mark_node;
     }
   else
Index: cp/decl.c
===================================================================
--- cp/decl.c	(revision 266840)
+++ cp/decl.c	(working copy)
@@ -12446,9 +12446,13 @@ grokdeclarator (const cp_declarator *declarator,
 	  {
 	    if (friendp)
 	      {
-		error_at (declarator->id_loc,
-			  "%qE is neither function nor member function; "
-			  "cannot be declared friend", unqualified_id);
+		if (unqualified_id && declarator)
+		  error_at (declarator->id_loc,
+			    "%qE is neither function nor member function; "
+			    "cannot be declared friend", unqualified_id);
+		else
+		  error ("unnamed field is neither function nor member "
+			 "function; cannot be declared friend");
 		return error_mark_node;
 	      }
 	    decl = NULL_TREE;
@@ -12536,7 +12540,9 @@ grokdeclarator (const cp_declarator *declarator,
 			      unqualified_id);
 		    constexpr_p = false;
 		  }
-		decl = build_decl (input_location,
+		decl = build_decl (declarator
+				   ? declarator->id_loc
+				   : input_location,
 				   FIELD_DECL, unqualified_id, type);
 		DECL_NONADDRESSABLE_P (decl) = bitfield;
 		if (bitfield && !unqualified_id)
Index: testsuite/g++.dg/other/bitfield2.C
===================================================================
--- testsuite/g++.dg/other/bitfield2.C	(revision 266840)
+++ testsuite/g++.dg/other/bitfield2.C	(working copy)
@@ -3,7 +3,7 @@
 
 struct A
 {
-  double d : 2;  // { dg-error "non-integral" }
+  double d : 2;  // { dg-error "10:bit-field .d. with non-integral type .double." }
   A() {}
   ~A() {}
 };
Index: testsuite/g++.dg/parse/bitfield1.C
===================================================================
--- testsuite/g++.dg/parse/bitfield1.C	(revision 266840)
+++ testsuite/g++.dg/parse/bitfield1.C	(working copy)
@@ -2,7 +2,7 @@
 
 struct A
 {
-  double i : 8; // { dg-error "type" }
+  double i : 8; // { dg-error "10:bit-field .i. with non-integral type .double." }
 };
 
 void foo(A& a)
Index: testsuite/g++.dg/parse/bitfield2.C
===================================================================
--- testsuite/g++.dg/parse/bitfield2.C	(revision 266840)
+++ testsuite/g++.dg/parse/bitfield2.C	(working copy)
@@ -4,7 +4,7 @@ struct X {};
 
 struct A
 {
-    X x : 2;            // { dg-error "non-integral type" }
+    X x : 2;            // { dg-error "7:bit-field .x. with non-integral type .X." }
 };
 struct B : A {};
 
@@ -19,7 +19,7 @@ C<int> c;
 template <typename T>
 struct D
 {
-  T t : 3;              // { dg-error "non-integral type" }
+  T t : 3;              // { dg-error "5:bit-field .double D\\<double\\>::t. with non-integral type .double." }
 };
 
 D<double> d;            // { dg-message "required" }
@@ -28,7 +28,7 @@ template <typename T>
 struct E
 {
   typedef T* U;
-  U t : 3;             // { dg-error "non-integral type" }
+  U t : 3;             // { dg-error "5:bit-field .t. with non-integral type .E\\<T\\>::U." }
 };
 
 E<double> e;
Index: testsuite/g++.dg/parse/bitfield7.C
===================================================================
--- testsuite/g++.dg/parse/bitfield7.C	(nonexistent)
+++ testsuite/g++.dg/parse/bitfield7.C	(working copy)
@@ -0,0 +1,4 @@
+struct A
+{
+  friend int : 1;  // { dg-error "unnamed field" }
+};