c++: constexpr new diagnostic location

Presenting the allocation location as the location of the outermost
expression we're trying to evaluate is inaccurate; let's provide both
locations.

gcc/cp/ChangeLog:

	* constexpr.cc (cxx_eval_outermost_constant_expr): Give both
	expression and allocation location in allocated storage diagnostics.

gcc/testsuite/ChangeLog:

	* g++.dg/cpp1y/constexpr-new.C: Adjust diagnostics.
	* g++.dg/cpp1z/constexpr-asm-5.C: Likewise.
	* g++.dg/cpp26/static_assert1.C: Likewise.
	* g++.dg/cpp2a/constexpr-dtor7.C: Likewise.
	* g++.dg/cpp2a/constexpr-new26.C: Likewise.
	* g++.dg/cpp2a/constexpr-new3.C: Likewise.
	* g++.dg/cpp2a/constinit14.C: Likewise.

gcc/cp/constexpr.cc

@@ -9262,9 +9262,11 @@ cxx_eval_outermost_constant_expr (tree t, bool allow_non_constant,
       if (heap_var)
 	{
 	  if (!allow_non_constant && !non_constant_p)
-	    error_at (DECL_SOURCE_LOCATION (heap_var),
-		      "%qE is not a constant expression because it refers to "
-		      "a result of %<operator new%>", t);
+	    {
+	      error ("%qE is not a constant expression because it refers to "
+		     "a result of %<operator new%>", t);
+	      inform (DECL_SOURCE_LOCATION (heap_var), "allocated here");
+	    }
 	  r = t;
 	  non_constant_p = true;
 	}
@@ -9273,9 +9275,11 @@ cxx_eval_outermost_constant_expr (tree t, bool allow_non_constant,
 	  if (DECL_NAME (heap_var) != heap_deleted_identifier)
 	    {
 	      if (!allow_non_constant && !non_constant_p)
-		error_at (DECL_SOURCE_LOCATION (heap_var),
-			  "%qE is not a constant expression because allocated "
-			  "storage has not been deallocated", t);
+		{
+		  error ("%qE is not a constant expression because allocated "
+			 "storage has not been deallocated", t);
+		  inform (DECL_SOURCE_LOCATION (heap_var), "allocated here");
+		}
 	      r = t;
 	      non_constant_p = true;
 	    }

gcc/testsuite/g++.dg/cpp1y/constexpr-new.C

@@ -6,7 +6,9 @@ constexpr int *f4(bool b) {
     return nullptr;
   } else {
     return new int{42}; // { dg-error "call to non-.constexpr." "" { target c++17_down } }
-  }			// { dg-error "is not a constant expression because allocated storage has not been deallocated" "" { target c++2a } .-1 }
+    // { dg-message "allocated here" "" { target c++20 } .-1 }
+  }
 }
 static_assert(f4(true) == nullptr, "");
-static_assert(f4(false) == nullptr, ""); // { dg-error "non-.constant. condition|" }
+static_assert(f4(false) == nullptr, ""); // { dg-error "non-constant condition" }
+// { dg-error "is not a constant expression because allocated storage has not been deallocated" "" { target c++20 } .-1 }

gcc/testsuite/g++.dg/cpp1z/constexpr-asm-5.C

@@ -28,7 +28,7 @@ struct M { constexpr K size () const { return {}; }
 	   constexpr L data () const { return {}; } };
 #if  __cpp_constexpr_dynamic_alloc >= 201907L
 struct N { constexpr int size () const { return 3; }
-	   constexpr const char *data () const { return new char[3] { 'b', 'a', 'd' }; } }; // { dg-error "'\\\* N\\\(\\\).N::data\\\(\\\)' is not a constant expression because allocated storage has not been deallocated" "" { target c++20 } }
+	   constexpr const char *data () const { return new char[3] { 'b', 'a', 'd' }; } };
 #endif
 constexpr const char a[] = { 't', 'e', 's', 't' };
 struct O { constexpr int size () const { return 4; }
@@ -117,6 +117,7 @@ foo ()
   asm ((M {}));
 #if __cpp_constexpr_dynamic_alloc >= 201907L
   asm ((N {}));			// { dg-error "constexpr string 'data\\\(\\\)\\\[0\\\]' must be a constant expression" "" { target c++20 } }
+ // { dg-error "'\\\* N\\\(\\\).N::data\\\(\\\)' is not a constant expression because allocated storage has not been deallocated" "" { target c++20 } .-1 }
 #endif
   asm ((O {}));
   asm ((P (0)));
@@ -190,6 +191,7 @@ bar ()
   asm ((M {}));
 #if __cpp_constexpr_dynamic_alloc >= 201907L
   asm ((N {}));			// { dg-error "constexpr string 'data\\\(\\\)\\\[0\\\]' must be a constant expression" "" { target c++20 } }
+ // { dg-error "'\\\* N\\\(\\\).N::data\\\(\\\)' is not a constant expression because allocated storage has not been deallocated" "" { target c++20 } .-1 }
 #endif
   asm ((O {}));
   asm ((P (0)));

gcc/testsuite/g++.dg/cpp26/static_assert1.C

@@ -69,10 +69,11 @@ static_assert (false, M {});	// { dg-warning "'static_assert' with non-string me
 				// { dg-error "static assertion failed: test" "" { target *-*-* } .-1 }
 #if  __cpp_constexpr_dynamic_alloc >= 201907L
 struct N { constexpr int size () const { return 3; }
-	   constexpr const char *data () const { return new char[3] { 'b', 'a', 'd' }; } }; // { dg-error "'\\\* N\\\(\\\).N::data\\\(\\\)' is not a constant expression because allocated storage has not been deallocated" "" { target c++20 } }
+	   constexpr const char *data () const { return new char[3] { 'b', 'a', 'd' }; } };
 static_assert (true, N {});	// { dg-warning "'static_assert' with non-string message only available with" "" { target { c++20 && c++23_down } } }
 static_assert (false, N {});	// { dg-warning "'static_assert' with non-string message only available with" "" { target { c++20 && c++23_down } } }
 				// { dg-error "constexpr string 'data\\\(\\\)\\\[0\\\]' must be a constant expression" "" { target c++20 } .-1 }
+				// { dg-error "'\\\* N\\\(\\\).N::data\\\(\\\)' is not a constant expression because allocated storage has not been deallocated" "" { target c++20 } .-2 }
 #endif
 constexpr const char a[] = { 't', 'e', 's', 't' };
 struct O { constexpr int size () const { return 4; }

gcc/testsuite/g++.dg/cpp2a/constexpr-dtor7.C

@@ -3,7 +3,7 @@
 
 struct S {
   int *s;
-  constexpr S () : s(new int) {}	// { dg-error "is not a constant expression because allocated storage has not been deallocated" }
+  constexpr S () : s(new int) {}
   S (const S &) = delete;
   S &operator= (const S &) = delete;
   constexpr ~S () { delete s; }
@@ -17,3 +17,4 @@ foo (S v)
 }
 
 static_assert (foo (S ()));	// { dg-error "non-constant condition for static assertion" }
+// { dg-error "is not a constant expression because allocated storage has not been deallocated" "" { target *-*-* } .-1 }

gcc/testsuite/g++.dg/cpp2a/constexpr-new26.C

@@ -4,7 +4,7 @@
 constexpr int *
 f7 ()
 {
-  int *p = new int (2);	// { dg-error "is not a constant expression because it refers to a result of" }
+  int *p = new int (2);		// { dg-message "allocated here" }
   delete p;
   return p;
 }
@@ -12,6 +12,5 @@ f7 ()
 void
 g ()
 {
-  constexpr auto v7 = f7 ();
+  constexpr auto v7 = f7 (); // { dg-error "is not a constant expression because it refers to a result of" }
 }
-

gcc/testsuite/g++.dg/cpp2a/constexpr-new3.C

@@ -5,19 +5,19 @@
 constexpr int *
 f1 ()
 {
-  return new int (2);		// { dg-error "is not a constant expression because it refers to a result of" }
+  return new int (2);		// { dg-message "allocated here" }
 }
 
-constexpr auto v1 = f1 ();
+constexpr auto v1 = f1 (); // { dg-error "is not a constant expression because it refers to a result of" }
 
 constexpr bool
 f2 ()
 {
-  int *p = new int (3);		// { dg-error "is not a constant expression because allocated storage has not been deallocated" }
+  int *p = new int (3);		// { dg-message "allocated here" }
   return false;
 }
 
-constexpr auto v2 = f2 ();
+constexpr auto v2 = f2 (); // { dg-error "is not a constant expression because allocated storage has not been deallocated" }
 
 constexpr bool
 f3 ()
@@ -64,12 +64,12 @@ constexpr auto v6 = f6 (); 	// { dg-message "in 'constexpr' expansion of" }
 constexpr int *
 f7 ()
 {
-  int *p = new int (2);		// { dg-error "is not a constant expression because it refers to a result of" }
+  int *p = new int (2);		// { dg-message "allocated here" }
   delete p;
   return p;
 }
 
-constexpr auto v7 = f7 ();
+constexpr auto v7 = f7 (); // { dg-error "is not a constant expression because it refers to a result of" }
 
 constexpr bool
 f8_impl (int *p)

gcc/testsuite/g++.dg/cpp2a/constinit14.C

@@ -2,12 +2,13 @@
 // { dg-do compile { target c++20 } }
 
 struct Value {
-  Value() : v{new int{42}} {}	// { dg-error "result of 'operator new'" "" { target implicit_constexpr } }
+  Value() : v{new int{42}} {}
   int* v;
 };
 
 struct S {
   static constinit inline Value v{}; // { dg-error "variable .S::v. does not have a constant initializer|call to non-.constexpr. function" }
+  // { dg-error "result of 'operator new'" "" { target implicit_constexpr } .-1 }
 };
 
 int main() { return *S::v.v; }