1------------------------------------------------------------------------------
2--                                                                          --
3--                         GNAT COMPILER COMPONENTS                         --
4--                                                                          --
5--                              E R R O U T C                               --
6--                                                                          --
7--                                 S p e c                                  --
8--                                                                          --
9--          Copyright (C) 1992-2015, Free Software Foundation, Inc.         --
10--                                                                          --
11-- GNAT is free software;  you can  redistribute it  and/or modify it under --
12-- terms of the  GNU General Public License as published  by the Free Soft- --
13-- ware  Foundation;  either version 3,  or (at your option) any later ver- --
14-- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
15-- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
16-- or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License --
17-- for  more details.  You should have  received  a copy of the GNU General --
18-- Public License  distributed with GNAT; see file COPYING3.  If not, go to --
19-- http://www.gnu.org/licenses for a complete copy of the license.          --
20--                                                                          --
21-- GNAT was originally developed  by the GNAT team at  New York University. --
22-- Extensive contributions were provided by Ada Core Technologies Inc.      --
23--                                                                          --
24------------------------------------------------------------------------------
25
26--  This packages contains global variables and routines common to error
27--  reporting packages, including Errout and Prj.Err.
28
29with Table;
30with Types; use Types;
31
32package Erroutc is
33
34   Class_Flag : Boolean := False;
35   --  This flag is set True when outputting a reference to a class-wide
36   --  type, and is used by Add_Class to insert 'Class at the proper point
37
38   Continuation : Boolean := False;
39   --  Indicates if current message is a continuation. Initialized from the
40   --  Msg_Cont parameter in Error_Msg_Internal and then set True if a \
41   --  insertion character is encountered.
42
43   Continuation_New_Line : Boolean := False;
44   --  Indicates if current message was a continuation line marked with \\ to
45   --  force a new line. Set True if \\ encountered.
46
47   Flag_Source : Source_File_Index;
48   --  Source file index for source file where error is being posted
49
50   Has_Double_Exclam : Boolean := False;
51   --  Set true to indicate that the current message contains the insertion
52   --  sequence !! (force warnings even in non-main unit source files).
53
54   Is_Serious_Error : Boolean := False;
55   --  Set True for a serious error (i.e. any message that is not a warning
56   --  or style message, and that does not contain a | insertion character).
57
58   Is_Unconditional_Msg : Boolean := False;
59   --  Set True to indicate that the current message contains the insertion
60   --  character ! and is thus to be treated as an unconditional message.
61
62   Is_Warning_Msg : Boolean := False;
63   --  Set True to indicate if current message is warning message (contains ?
64   --  or contains < and Error_Msg_Warn is True.
65
66   Is_Info_Msg : Boolean := False;
67   --  Set True to indicate that the current message starts with the characters
68   --  "info: " and is to be treated as an information message. This string
69   --  will be prepended to the message and all its continuations.
70
71   Is_Check_Msg : Boolean := False;
72   --  Set True to indicate that the current message starts with one of
73   --  "high: ", "medium: ", "low: " and is to be treated as a check message.
74
75   Warning_Msg_Char : Character;
76   --  Warning character, valid only if Is_Warning_Msg is True
77   --    ' '      -- ?   or <   appeared on its own in message
78   --    '?'      -- ??  or <<  appeared in message
79   --    'x'      -- ?x? or <x< appeared in message (x = a .. z)
80   --    'X'      -- ?X? or <X< appeared in message (X = A .. Z)
81   --    '*'      -- ?*? or <*< appeared in message
82   --    '$'      -- ?$? or <$< appeared in message
83   --  In the case of the < sequences, this is set only if the message is
84   --  actually a warning, i.e. if Error_Msg_Warn is True
85
86   Is_Style_Msg : Boolean := False;
87   --  Set True to indicate if the current message is a style message
88   --  (i.e. a message whose text starts with the characters "(style)").
89
90   Kill_Message : Boolean := False;
91   --  A flag used to kill weird messages (e.g. those containing uninterpreted
92   --  implicit type references) if we have already seen at least one message
93   --  already. The idea is that we hope the weird message is a junk cascaded
94   --  message that should be suppressed.
95
96   Last_Killed : Boolean := False;
97   --  Set True if the most recently posted non-continuation message was
98   --  killed. This is used to determine the processing of any continuation
99   --  messages that follow.
100
101   List_Pragmas_Index : Int := 0;
102   --  Index into List_Pragmas table
103
104   List_Pragmas_Mode : Boolean := False;
105   --  Starts True, gets set False by pragma List (Off), True by List (On)
106
107   Manual_Quote_Mode : Boolean := False;
108   --  Set True in manual quotation mode
109
110   Max_Msg_Length : constant := 1024 + 2 * Int (Column_Number'Last);
111   --  Maximum length of error message. The addition of 2 * Column_Number'Last
112   --  ensures that two insertion tokens of maximum length can be accommodated.
113   --  The value of 1024 is an arbitrary value that should be more than long
114   --  enough to accommodate any reasonable message (and for that matter, some
115   --  pretty unreasonable messages).
116
117   Msg_Buffer : String (1 .. Max_Msg_Length);
118   --  Buffer used to prepare error messages
119
120   Msglen : Integer := 0;
121   --  Number of characters currently stored in the message buffer
122
123   Suppress_Message : Boolean;
124   --  A flag used to suppress certain obviously redundant messages (i.e.
125   --  those referring to a node whose type is Any_Type). This suppression
126   --  is effective only if All_Errors_Mode is off.
127
128   Suppress_Instance_Location : Boolean := False;
129   --  Normally, if a # location in a message references a location within
130   --  a generic template, then a note is added giving the location of the
131   --  instantiation. If this variable is set True, then this note is not
132   --  output. This is used for internal processing for the case of an
133   --  illegal instantiation. See Error_Msg routine for further details.
134
135   ----------------------------
136   -- Message ID Definitions --
137   ----------------------------
138
139   type Error_Msg_Id is new Int;
140   --  A type used to represent specific error messages. Used by the clients
141   --  of this package only in the context of the Get_Error_Id and
142   --  Change_Error_Text subprograms.
143
144   No_Error_Msg : constant Error_Msg_Id := 0;
145   --  A constant which is different from any value returned by Get_Error_Id.
146   --  Typically used by a client to indicate absence of a saved Id value.
147
148   Cur_Msg : Error_Msg_Id := No_Error_Msg;
149   --  Id of most recently posted error message
150
151   function Get_Msg_Id return Error_Msg_Id;
152   --  Returns the Id of the message most recently posted using one of the
153   --  Error_Msg routines.
154
155   function Get_Location (E : Error_Msg_Id) return Source_Ptr;
156   --  Returns the flag location of the error message with the given id E
157
158   -----------------------------------
159   -- Error Message Data Structures --
160   -----------------------------------
161
162   --  The error messages are stored as a linked list of error message objects
163   --  sorted into ascending order by the source location (Sloc). Each object
164   --  records the text of the message and its source location.
165
166   --  The following record type and table are used to represent error
167   --  messages, with one entry in the table being allocated for each message.
168
169   type Error_Msg_Object is record
170      Text : String_Ptr;
171      --  Text of error message, fully expanded with all insertions
172
173      Next : Error_Msg_Id;
174      --  Pointer to next message in error chain. A value of No_Error_Msg
175      --  indicates the end of the chain.
176
177      Prev : Error_Msg_Id;
178      --  Pointer to previous message in error chain. Only set during the
179      --  Finalize procedure. A value of No_Error_Msg indicates the first
180      --  message in the chain.
181
182      Sfile : Source_File_Index;
183      --  Source table index of source file. In the case of an error that
184      --  refers to a template, always references the original template
185      --  not an instantiation copy.
186
187      Sptr : Source_Ptr;
188      --  Flag pointer. In the case of an error that refers to a template,
189      --  always references the original template, not an instantiation copy.
190      --  This value is the actual place in the source that the error message
191      --  will be posted. Note that an error placed on an instantiation will
192      --  have Sptr pointing to the instantiation point.
193
194      Optr : Source_Ptr;
195      --  Flag location used in the call to post the error. This is normally
196      --  the same as Sptr, except when an error is posted on a particular
197      --  instantiation of a generic. In such a case, Sptr will point to
198      --  the original source location of the instantiation itself, but
199      --  Optr will point to the template location (more accurately to the
200      --  template copy in the instantiation copy corresponding to the
201      --  instantiation referenced by Sptr).
202
203      Line : Physical_Line_Number;
204      --  Line number for error message
205
206      Col : Column_Number;
207      --  Column number for error message
208
209      Warn : Boolean;
210      --  True if warning message
211
212      Info : Boolean;
213      --  True if info message
214
215      Check : Boolean;
216      --  True if check message
217
218      Warn_Err : Boolean;
219      --  True if this is a warning message which is to be treated as an error
220      --  as a result of a match with a Warning_As_Error pragma.
221
222      Warn_Chr : Character;
223      --  Warning character (note: set even if Warning_Doc_Switch is False)
224      --    ' '      -- ?   or <   appeared on its own in message
225      --    '?'      -- ??  or <<  appeared in message
226      --    'x'      -- ?x? or <x< appeared in message (x = a .. z)
227      --    'X'      -- ?X? or <X< appeared in message (X = A .. Z)
228      --    '*'      -- ?*? or <*< appeared in message
229      --    '$'      -- ?$? or <$< appeared in message
230      --  In the case of the < sequences, this is set only if the message is
231      --  actually a warning, i.e. if Error_Msg_Warn is True
232
233      Style : Boolean;
234      --  True if style message (starts with "(style)")
235
236      Serious : Boolean;
237      --  True if serious error message (not a warning and no | character)
238
239      Uncond : Boolean;
240      --  True if unconditional message (i.e. insertion character ! appeared)
241
242      Msg_Cont : Boolean;
243      --  This is used for logical messages that are composed of multiple
244      --  individual messages. For messages that are not part of such a
245      --  group, or that are the first message in such a group. Msg_Cont
246      --  is set to False. For subsequent messages in a group, Msg_Cont
247      --  is set to True. This is used to make sure that such a group of
248      --  messages is either suppressed or retained as a group (e.g. in
249      --  the circuit that deletes identical messages).
250
251      Deleted : Boolean;
252      --  If this flag is set, the message is not printed. This is used
253      --  in the circuit for deleting duplicate/redundant error messages.
254   end record;
255
256   package Errors is new Table.Table (
257     Table_Component_Type => Error_Msg_Object,
258     Table_Index_Type     => Error_Msg_Id,
259     Table_Low_Bound      => 1,
260     Table_Initial        => 200,
261     Table_Increment      => 200,
262     Table_Name           => "Error");
263
264   First_Error_Msg : Error_Msg_Id;
265   --  The list of error messages, i.e. the first entry on the list of error
266   --  messages. This is not the same as the physically first entry in the
267   --  error message table, since messages are not always inserted in sequence.
268
269   Last_Error_Msg : Error_Msg_Id;
270   --  The last entry on the list of error messages. Note: this is not the same
271   --  as the physically last entry in the error message table, since messages
272   --  are not always inserted in sequence.
273
274   --------------------------
275   -- Warning Mode Control --
276   --------------------------
277
278   --  Pragma Warnings allows warnings to be turned off for a specified region
279   --  of code, and the following tables are the data structures used to keep
280   --  track of these regions.
281
282   --  The first table is used for the basic command line control, and for the
283   --  forms of Warning with a single ON or OFF parameter.
284
285   --  It contains pairs of source locations, the first being the start
286   --  location for a warnings off region, and the second being the end
287   --  location. When a pragma Warnings (Off) is encountered, a new entry is
288   --  established extending from the location of the pragma to the end of the
289   --  current source file. A subsequent pragma Warnings (On) adjusts the end
290   --  point of this entry appropriately.
291
292   --  If all warnings are suppressed by command switch, then there is a dummy
293   --  entry (put there by Errout.Initialize) at the start of the table which
294   --  covers all possible Source_Ptr values. Note that the source pointer
295   --  values in this table always reference the original template, not an
296   --  instantiation copy, in the generic case.
297
298   --  Reason is the reason from the pragma Warnings (Off,..) or the null
299   --  string if no reason parameter is given.
300
301   type Warnings_Entry is record
302      Start  : Source_Ptr;
303      Stop   : Source_Ptr;
304      Reason : String_Id;
305   end record;
306
307   package Warnings is new Table.Table (
308     Table_Component_Type => Warnings_Entry,
309     Table_Index_Type     => Natural,
310     Table_Low_Bound      => 1,
311     Table_Initial        => 100,
312     Table_Increment      => 200,
313     Table_Name           => "Warnings");
314
315   --  The second table is used for the specific forms of the pragma, where
316   --  the first argument is ON or OFF, and the second parameter is a string
317   --  which is the pattern to match for suppressing a warning.
318
319   type Specific_Warning_Entry is record
320      Start : Source_Ptr;
321      Stop  : Source_Ptr;
322      --  Starting and ending source pointers for the range. These are always
323      --  from the same source file.
324
325      Reason : String_Id;
326      --  Reason string from pragma Warnings, or null string if none
327
328      Msg : String_Ptr;
329      --  Message from pragma Warnings (Off, string)
330
331      Open : Boolean;
332      --  Set to True if OFF has been encountered with no matching ON
333
334      Used : Boolean;
335      --  Set to True if entry has been used to suppress a warning
336
337      Config : Boolean;
338      --  True if pragma is configuration pragma (in which case no matching Off
339      --  pragma is required, and it is not required that a specific warning be
340      --  suppressed).
341   end record;
342
343   package Specific_Warnings is new Table.Table (
344     Table_Component_Type => Specific_Warning_Entry,
345     Table_Index_Type     => Natural,
346     Table_Low_Bound      => 1,
347     Table_Initial        => 100,
348     Table_Increment      => 200,
349     Table_Name           => "Specific_Warnings");
350
351   --  Note on handling configuration case versus specific case. A complication
352   --  arises from this example:
353
354   --     pragma Warnings (Off, "not referenced*");
355   --     procedure Mumble (X : Integer) is
356   --     pragma Warnings (On, "not referenced*");
357   --     begin
358   --        null;
359   --     end Mumble;
360
361   --  The trouble is that the first pragma is technically a configuration
362   --  pragma, and yet it is clearly being used in the context of thinking of
363   --  it as a specific case. To deal with this, what we do is that the On
364   --  entry can match a configuration pragma from the same file, and if we
365   --  find such an On entry, we cancel the indication of it being the
366   --  configuration case. This seems to handle all cases we run into ok.
367
368   -----------------
369   -- Subprograms --
370   -----------------
371
372   procedure Add_Class;
373   --  Add 'Class to buffer for class wide type case (Class_Flag set)
374
375   function Buffer_Ends_With (C : Character) return Boolean;
376   --  Tests if message buffer ends with given character
377
378   function Buffer_Ends_With (S : String) return Boolean;
379   --  Tests if message buffer ends with given string preceded by a space
380
381   procedure Buffer_Remove (C : Character);
382   --  Remove given character fron end of buffer if it is present
383
384   procedure Buffer_Remove (S : String);
385   --  Removes given string from end of buffer if it is present at end of
386   --  buffer, and preceded by a space.
387
388   function Compilation_Errors return Boolean;
389   --  Returns true if errors have been detected, or warnings in -gnatwe
390   --  (treat warnings as errors) mode.
391
392   procedure dmsg (Id : Error_Msg_Id);
393   --  Debugging routine to dump an error message
394
395   procedure Debug_Output (N : Node_Id);
396   --  Called from Error_Msg_N and Error_Msg_NE to generate line of debug
397   --  output giving node number (of node N) if the debug X switch is set.
398
399   procedure Check_Duplicate_Message (M1, M2 : Error_Msg_Id);
400   --  This function is passed the Id values of two error messages. If either
401   --  M1 or M2 is a continuation message, or is already deleted, the call is
402   --  ignored. Otherwise a check is made to see if M1 and M2 are duplicated or
403   --  redundant. If so, the message to be deleted and all its continuations
404   --  are marked with the Deleted flag set to True.
405
406   function Get_Warning_Tag (Id : Error_Msg_Id) return String;
407   --  Given an error message ID, return tag showing warning message class, or
408   --  the null string if this option is not enabled or this is not a warning.
409
410   procedure Output_Error_Msgs (E : in out Error_Msg_Id);
411   --  Output source line, error flag, and text of stored error message and all
412   --  subsequent messages for the same line and unit. On return E is set to be
413   --  one higher than the last message output.
414
415   procedure Output_Line_Number (L : Logical_Line_Number);
416   --  Output a line number as six digits (with leading zeroes suppressed),
417   --  followed by a period and a blank (note that this is 8 characters which
418   --  means that tabs in the source line will not get messed up). Line numbers
419   --  that match or are less than the last Source_Reference pragma are listed
420   --  as all blanks, avoiding output of junk line numbers.
421
422   procedure Output_Msg_Text (E : Error_Msg_Id);
423   --  Outputs characters of text in the text of the error message E. Note that
424   --  no end of line is output, the caller is responsible for adding the end
425   --  of line. If Error_Msg_Line_Length is non-zero, this is the routine that
426   --  splits the line generating multiple lines of output, and in this case
427   --  the last line has no terminating end of line character.
428
429   procedure Prescan_Message (Msg : String);
430   --  Scans message text and sets the following variables:
431   --
432   --    Is_Warning_Msg is set True if Msg is a warning message (contains a
433   --    question mark character), and False otherwise.
434   --
435   --    Is_Style_Msg is set True if Msg is a style message (starts with
436   --    "(style)") and False otherwise.
437   --
438   --    Is_Info_Msg is set True if Msg is an information message (starts
439   --    with "info: ". Such messages must contain a ? sequence since they
440   --    are also considered to be warning messages, and get a tag.
441   --
442   --    Is_Serious_Error is set to True unless the message is a warning or
443   --    style message or contains the character | (non-serious error).
444   --
445   --    Is_Unconditional_Msg is set True if the message contains the character
446   --    ! and is otherwise set False.
447   --
448   --    Has_Double_Exclam is set True if the message contains the sequence !!
449   --    and is otherwise set False.
450   --
451   --  We need to know right away these aspects of a message, since we will
452   --  test these values before doing the full error scan.
453   --
454   --  Note that the call has no effect for continuation messages (those whose
455   --  first character is '\'), and all variables are left unchanged.
456
457   procedure Purge_Messages (From : Source_Ptr; To : Source_Ptr);
458   --  All error messages whose location is in the range From .. To (not
459   --  including the end points) will be deleted from the error listing.
460
461   function Same_Error (M1, M2 : Error_Msg_Id) return Boolean;
462   --  See if two messages have the same text. Returns true if the text of the
463   --  two messages is identical, or if one of them is the same as the other
464   --  with an appended "instance at xxx" tag.
465
466   procedure Set_Msg_Blank;
467   --  Sets a single blank in the message if the preceding character is a
468   --  non-blank character other than a left parenthesis or minus. Has no
469   --  effect if manual quote mode is turned on.
470
471   procedure Set_Msg_Blank_Conditional;
472   --  Sets a single blank in the message if the preceding character is a
473   --  non-blank character other than a left parenthesis or quote. Has no
474   --  effect if manual quote mode is turned on.
475
476   procedure Set_Msg_Char (C : Character);
477   --  Add a single character to the current message. This routine does not
478   --  check for special insertion characters (they are just treated as text
479   --  characters if they occur).
480
481   procedure Set_Msg_Insertion_File_Name;
482   --  Handle file name insertion (left brace insertion character)
483
484   procedure Set_Msg_Insertion_Line_Number (Loc, Flag : Source_Ptr);
485   --  Handle line number insertion (# insertion character). Loc is the
486   --  location to be referenced, and Flag is the location at which the
487   --  flag is posted (used to determine whether to add "in file xxx")
488
489   procedure Set_Msg_Insertion_Name_Literal;
490
491   procedure Set_Msg_Insertion_Name;
492   --  Handle name insertion (% insertion character)
493
494   procedure Set_Msg_Insertion_Reserved_Name;
495   --  Handle insertion of reserved word name (* insertion character)
496
497   procedure Set_Msg_Insertion_Reserved_Word
498     (Text : String;
499      J    : in out Integer);
500   --  Handle reserved word insertion (upper case letters). The Text argument
501   --  is the current error message input text, and J is an index which on
502   --  entry points to the first character of the reserved word, and on exit
503   --  points past the last character of the reserved word. Note that RM and
504   --  SPARK are treated specially and not considered to be keywords.
505
506   procedure Set_Msg_Insertion_Run_Time_Name;
507   --  If package System contains a definition for Run_Time_Name (see package
508   --  Targparm for details), then this procedure will insert a message of
509   --  the form (name) into the current error message, with name set in mixed
510   --  case (upper case after any spaces). If no run time name is defined,
511   --  then this routine has no effect).
512
513   procedure Set_Msg_Insertion_Uint;
514   --  Handle Uint insertion (^ insertion character)
515
516   procedure Set_Msg_Int (Line : Int);
517   --  Set the decimal representation of the argument in the error message
518   --  buffer with no leading zeroes output.
519
520   procedure Set_Msg_Name_Buffer;
521   --  Output name from Name_Buffer, with surrounding quotes unless manual
522   --  quotation mode is in effect.
523
524   procedure Set_Msg_Quote;
525   --  Set quote if in normal quote mode, nothing if in manual quote mode
526
527   procedure Set_Msg_Str (Text : String);
528   --  Add a sequence of characters to the current message. This routine does
529   --  not check for special insertion characters (they are just treated as
530   --  text characters if they occur). It does perform the transformation of
531   --  the special strings _xxx (xxx = Pre/Post/Type_Invariant) to xxx'Class.
532
533   procedure Set_Next_Non_Deleted_Msg (E : in out Error_Msg_Id);
534   --  Given a message id, move to next message id, but skip any deleted
535   --  messages, so that this results in E on output being the first non-
536   --  deleted message following the input value of E, or No_Error_Msg if
537   --  the input value of E was either already No_Error_Msg, or was the
538   --  last non-deleted message.
539
540   procedure Set_Specific_Warning_Off
541     (Loc    : Source_Ptr;
542      Msg    : String;
543      Reason : String_Id;
544      Config : Boolean;
545      Used   : Boolean := False);
546   --  This is called in response to the two argument form of pragma Warnings
547   --  where the first argument is OFF, and the second argument is a string
548   --  which identifies a specific warning to be suppressed. The first argument
549   --  is the start of the suppression range, and the second argument is the
550   --  string from the pragma. Loc is the location of the pragma (which is the
551   --  start of the range to suppress). Reason is the reason string from the
552   --  pragma, or the null string if no reason is given. Config is True for the
553   --  configuration pragma case (where there is no requirement for a matching
554   --  OFF pragma). Used is set True to disable the check that the warning
555   --  actually has the effect of suppressing a warning.
556
557   procedure Set_Specific_Warning_On
558     (Loc : Source_Ptr;
559      Msg : String;
560      Err : out Boolean);
561   --  This is called in response to the two argument form of pragma Warnings
562   --  where the first argument is ON, and the second argument is a string
563   --  which identifies a specific warning to be suppressed. The first argument
564   --  is the end of the suppression range, and the second argument is the
565   --  string from the pragma. Err is set to True on return to report the error
566   --  of no matching Warnings Off pragma preceding this one.
567
568   procedure Set_Warnings_Mode_Off (Loc : Source_Ptr; Reason : String_Id);
569   --  Called in response to a pragma Warnings (Off) to record the source
570   --  location from which warnings are to be turned off. Reason is the
571   --  Reason from the pragma, or the null string if none is given.
572
573   procedure Set_Warnings_Mode_On (Loc : Source_Ptr);
574   --  Called in response to a pragma Warnings (On) to record the source
575   --  location from which warnings are to be turned back on.
576
577   function Warnings_Suppressed (Loc : Source_Ptr) return String_Id;
578   --  Determines if given location is covered by a warnings off suppression
579   --  range in the warnings table (or is suppressed by compilation option,
580   --  which generates a warning range for the whole source file). This routine
581   --  only deals with the general ON/OFF case, not specific warnings. The
582   --  returned result is No_String if warnings are not suppressed. If warnings
583   --  are suppressed for the given location, then corresponding Reason
584   --  parameter from the pragma is returned (or the null string if no Reason
585   --  parameter was present).
586
587   function Warning_Specifically_Suppressed
588     (Loc : Source_Ptr;
589      Msg : String_Ptr;
590      Tag : String := "") return String_Id;
591   --  Determines if given message to be posted at given location is suppressed
592   --  by specific ON/OFF Warnings pragmas specifying this particular message.
593   --  If the warning is not suppressed then No_String is returned, otherwise
594   --  the corresponding warning string is returned (or the null string if no
595   --  Warning argument was present in the pragma). Tag is the error message
596   --  tag for the message in question or the null string if there is no tag.
597   --
598   --  Note: we have a null default for Tag to deal with calls from an old
599   --  branch of gnat2why, which does not know about tags in the calls but
600   --  which uses the latest version of erroutc.
601
602   function Warning_Treated_As_Error (Msg : String) return Boolean;
603   --  Returns True if the warning message Msg matches any of the strings
604   --  given by Warning_As_Error pragmas, as stored in the Warnings_As_Errors
605   --  table by Set_Warning_As_Error.
606
607   type Error_Msg_Proc is
608     access procedure (Msg : String; Flag_Location : Source_Ptr);
609   procedure Validate_Specific_Warnings (Eproc : Error_Msg_Proc);
610   --  Checks that specific warnings are consistent (for non-configuration
611   --  case, properly closed, and used). The argument is a pointer to the
612   --  Error_Msg procedure to be called if any inconsistencies are detected.
613
614end Erroutc;
615