[Ada] Removal of technical debt

gcc/ada/

	* exp_ch6.adb (Add_Simple_Call_By_Copy_Code): Add comments
	regarding special handling of components which depend on
	discriminants.
	* exp_dist.adb (Build_From_Any_Function): Add Real_Rep actual
	for calls to Has_Stream_Attribute_Definition.
	(Build_To_Any_Function): Likewise.
	(Build_TypeCode_Function): Likewise.
	* freeze.adb (Freeze_Entity): Add missing comment for Test_E.
	* libgnat/s-utf_32.adb: Remove disabled warning comments and
	temporarily inserted pragma warnings.  Remove very old (2006 and
	2012) comments about bootstrapping older versions.
	* par.adb (P_Identifier): Add new parameter Force_Msg.
	* par-ch2.adb (P_Identifier): Restructure and clean up function.
	* par-ch3.adb (P_Defining_Identifier): Remove code duplication
	for parsing identifiers.
	* sem_attr.adb (Stream_Attribute_Available): Add missing
	comments and add Real_Rep actual for calls to
	Has_Stream_Attribute_Definition.
	* sem_cat.adb (Has_Read_Write_Attribute): Add Real_Rep actual
	for calls to Has_Stream_Attribute_Definition.
	(Has_Stream_Attribute_Definition): Remove local Real_Rep and fix
	recursive calls. Add default value for Real_Rep.
	* sem_cat.ads (Has_Stream_Attribute_Definition): Add new out
	parameter "Real_Rep".
	* sem_type.adb (Add_Entry): Add condition to avoid passing
	non-function calls to Function_Interp_Has_Abstract_Op.
	(Function_Interp_Has_Abstract_Op): Add missing comments and
	remove check for Is_Overloadable.
	* sem_util.adb (Derivation_Too_Early_To_Inherit): Remove
	duplicated code.

1 files changed, 7 insertions, 1 deletions

diff --git a/gcc/ada/par.adb b/gcc/ada/par.adb
index 312c41100d5..c577d283c42 100644
--- a/gcc/ada/par.adb
+++ b/gcc/ada/par.adb
@@ -649,10 +649,16 @@ function Par (Configuration_Pragmas : Boolean) return List_Id is
       --  procedure more than once for the same pragma. All parse-time pragma
       --  handling must be prepared to handle such multiple calls correctly.
 
-      function P_Identifier (C : Id_Check := None) return Node_Id;
+      function P_Identifier
+        (C         : Id_Check := None;
+         Force_Msg : Boolean  := False) return Node_Id;
       --  Scans out an identifier. The parameter C determines the treatment
       --  of reserved identifiers. See declaration of Id_Check for details.
 
+      --  An appropriate error message, pointing to the token, is also issued
+      --  if either this is the first occurrence of misuse of this identifier,
+      --  or if Force_Msg is True.
+
       function P_Pragmas_Opt return List_Id;
       --  This function scans for a sequence of pragmas in other than a
       --  declaration sequence or statement sequence context. All pragmas