PR modula2/116048 ICE when encountering wrong kind of qualident

Following on from PR-115957 further ICEs can be generated by using the
wrong kind of qualident symbol.  For example using a variable instead of
a type or using a type instead of a const.  This fix tracks the expected
qualident kind state when parsing const, type and variable declarations.
If the error is unrecoverable then a detailed message explaining the
context of the qualident (and why the seen qualident is wrong) is
generated.

gcc/m2/ChangeLog:

	PR modula2/116048
	* Make-lang.in (GM2-COMP-BOOT-DEFS): Add M2StateCheck.def.
	(GM2-COMP-BOOT-MODS): Add M2StateCheck.mod.
	(GM2-COMP-DEFS): Add M2StateCheck.def.
	(GM2-COMP-MODS): Add M2StateCheck.mod.
	* gm2-compiler/M2Quads.mod (StartBuildWith): Generate
	unrecoverable error is the qualident type is NulSym.
	Replace MetaError1 with MetaErrorT1 and position the error
	to the qualident.
	* gm2-compiler/P3Build.bnf (M2StateCheck): Import procedures.
	(seenError): New variable.
	(WasNoError): Remove variable.
	(BlockState): New variable.
	(ErrorString): Rewrite using seenError.
	(CompilationUnit): Ditto.
	(QualidentCheck): New rule.
	(ConstantDeclaration): Bookend with InclConst and ExclConst.
	(Constructor): Add InclConstructor, ExclConstructor and call
	CheckQualident.
	(ConstActualParameters): Call PushState, PopState, InclConstFunc
	and CheckQualident.
	(TypeDeclaration): Bookend with InclType and ExclType.
	(SimpleType): Call QualidentCheck.
	(CaseTag): Ditto.
	(OptReturnType): Ditto.
	(VariableDeclaration): Bookend with InclVar and ExclVar.
	(Designator): Call QualidentCheck.
	(Formal;Type): Ditto.
	* gm2-compiler/PCBuild.bnf (M2StateCheck): Import procedures.
	(ConstantDeclaration): Rewrite using InclConst and ExclConst.
	(Constructor): Bookend with InclConstructor and ExclConstructor.
	Call CheckQualident.
	(ConstructorOrConstActualParameters): Rewrite and cal
	l CheckQualident.
	(ConstActualParameters): Bookend with PushState PopState.
	Call InclConstFunc and CheckQualident.
	* gm2-gcc/init.cc (_M2_M2StateCheck_init): New declaration.
	(_M2_P3Build_init): New declaration.
	(init_PerCompilationInit): Call _M2_M2StateCheck_init and
	_M2_P3Build_init.
	* gm2-compiler/M2StateCheck.def: New file.
	* gm2-compiler/M2StateCheck.mod: New file.

gcc/testsuite/ChangeLog:

	PR modula2/116048
	* gm2/errors/fail/errors-fail.exp: Remove -Wstudents
	and add -Wuninit-variable-checking=all.
	Replace gm2_init_pim with gm2_init_iso.
	* gm2/errors/fail/testfio.mod: Modify test code to
	provoke an error in the first basic block.
	* gm2/errors/fail/testparam.mod: Ditto.
	* gm2/errors/fail/array1.mod: Ditto.
	* gm2/errors/fail/badtype.mod: New test.
	* gm2/errors/fail/badvar.mod: New test.

Signed-off-by: Gaius Mulley <gaiusmod2@gmail.com>

13 files changed, 645 insertions, 56 deletions

diff --git a/gcc/m2/Make-lang.in b/gcc/m2/Make-lang.in
index daa7ef6..2bd60ca 100644
--- a/gcc/m2/Make-lang.in
+++ b/gcc/m2/Make-lang.in
@@ -808,6 +808,7 @@ GM2-COMP-BOOT-DEFS = \
    M2Size.def \
    M2StackAddress.def \
    M2StackWord.def \
+   M2StateCheck.def \
    M2Students.def \
    M2Swig.def \
    M2SymInit.def \
@@ -882,6 +883,7 @@ GM2-COMP-BOOT-MODS = \
    M2Size.mod \
    M2StackAddress.mod \
    M2StackWord.mod \
+   M2StateCheck.mod \
    M2Students.mod \
    M2Swig.mod \
    M2SymInit.mod \
@@ -1090,6 +1092,7 @@ GM2-COMP-DEFS = \
    M2Size.def \
    M2StackAddress.def \
    M2StackWord.def \
+   M2StateCheck.def \
    M2Students.def \
    M2Swig.def \
    M2SymInit.def \
@@ -1161,6 +1164,7 @@ GM2-COMP-MODS = \
    M2Size.mod \
    M2StackAddress.mod \
    M2StackWord.mod \
+   M2StateCheck.mod \
    M2Students.mod \
    M2Swig.mod \
    M2SymInit.mod \
diff --git a/gcc/m2/gm2-compiler/M2Quads.mod b/gcc/m2/gm2-compiler/M2Quads.mod
index 6476806..6230bf7 100644
--- a/gcc/m2/gm2-compiler/M2Quads.mod
+++ b/gcc/m2/gm2-compiler/M2Quads.mod
@@ -12068,31 +12068,34 @@ BEGIN
    PopTFtok (Sym, Type, tok) ;
    DebugLocation (tok, "expression") ;
    Type := SkipType (Type) ;
-
-   Ref := MakeTemporary (tok, LeftValue) ;
-   PutVar (Ref, Type) ;
-   IF GetMode (Sym) = LeftValue
+   IF Type = NulSym
    THEN
-      (* Copy LeftValue.  *)
-      GenQuadO (tok, BecomesOp, Ref, NulSym, Sym, TRUE)
+      MetaErrorT1 (tok,
+                   '{%1Aa} {%1d} has a no type, the {%kWITH} statement requires a variable or parameter of a {%kRECORD} type',
+                   Sym)
    ELSE
-      (* Calculate the address of Sym.  *)
-      GenQuadO (tok, AddrOp, Ref, NulSym, Sym, TRUE)
-   END ;
+      Ref := MakeTemporary (tok, LeftValue) ;
+      PutVar (Ref, Type) ;
+      IF GetMode (Sym) = LeftValue
+      THEN
+         (* Copy LeftValue.  *)
+         GenQuadO (tok, BecomesOp, Ref, NulSym, Sym, TRUE)
+      ELSE
+         (* Calculate the address of Sym.  *)
+         GenQuadO (tok, AddrOp, Ref, NulSym, Sym, TRUE)
+      END ;
 
-   PushWith (Sym, Type, Ref, tok) ;
-   DebugLocation (tok, "with ref") ;
-   IF Type = NulSym
-   THEN
-      MetaError1 ('{%1Ea} {%1d} has a no type, the {%kWITH} statement requires a variable or parameter of a {%kRECORD} type',
-                  Sym)
-   ELSIF NOT IsRecord(Type)
-   THEN
-      MetaError1 ('the {%kWITH} statement requires that {%1Ea} {%1d} be of a {%kRECORD} {%1tsa:type rather than {%1tsa}}',
-		   Sym)
+      PushWith (Sym, Type, Ref, tok) ;
+      DebugLocation (tok, "with ref") ;
+      IF NOT IsRecord(Type)
+      THEN
+         MetaErrorT1 (tok,
+                      'the {%kWITH} statement requires that {%1Ea} {%1d} be of a {%kRECORD} {%1tsa:type rather than {%1tsa}}',
+                      Sym)
+      END ;
+      StartScope (Type)
    END ;
-   StartScope (Type)
- ; DisplayStack ;
+   DisplayStack ;
 END StartBuildWith ;
 
 
diff --git a/gcc/m2/gm2-compiler/M2StateCheck.def b/gcc/m2/gm2-compiler/M2StateCheck.def
new file mode 100644
index 0000000..ca597c2
--- /dev/null
+++ b/gcc/m2/gm2-compiler/M2StateCheck.def
@@ -0,0 +1,154 @@
+(* M2StateCheck.def provide state check tracking for declarations.
+
+Copyright (C) 2024 Free Software Foundation, Inc.
+Contributed by Gaius Mulley <gaiusmod2@gmail.com>.
+
+This file is part of GNU Modula-2.
+
+GNU Modula-2 is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 3, or (at your option)
+any later version.
+
+GNU Modula-2 is distributed in the hope that it will be useful, but
+WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with GNU Modula-2; see the file COPYING3.  If not see
+<http://www.gnu.org/licenses/>.  *)
+
+DEFINITION MODULE M2StateCheck ;
+
+(* This module provides state tracking for VAR, TYPE and CONST
+   declarations.  It should be used by any pass creating
+   symbols in these blocks and it will detect a constant
+   being created from a variable, type from a variable,
+   variable from a constant (instead of type) etc.  *)
+
+TYPE
+   StateCheck ;
+
+
+(*
+   InitState - returns a new initialized StateCheck.
+*)
+
+PROCEDURE InitState () : StateCheck ;
+
+
+(*
+   KillState - destructor for StateCheck.
+*)
+
+PROCEDURE KillState (VAR s: StateCheck) ;
+
+
+(*
+   PushState - duplicates the StateCheck s and chains the new copy to s.
+               Return the copy.
+*)
+
+PROCEDURE PushState (VAR s: StateCheck) ;
+
+
+(*
+   PopState - pops the current state.
+*)
+
+PROCEDURE PopState (VAR s: StateCheck) ;
+
+
+(*
+   InclVar - s := s + {var}.
+*)
+
+PROCEDURE InclVar (s: StateCheck) ;
+
+
+(*
+   InclConst - s := s + {const}.
+*)
+
+PROCEDURE InclConst (s: StateCheck) ;
+
+
+(*
+   InclType - s := s + {type}.
+*)
+
+PROCEDURE InclType (s: StateCheck) ;
+
+
+(*
+   InclConstFunc - s := s + {constfunc}.
+*)
+
+PROCEDURE InclConstFunc (s: StateCheck) ;
+
+
+(*
+   InclVarParam - s := s + {varparam}.
+*)
+
+PROCEDURE InclVarParam (s: StateCheck) ;
+
+
+(*
+   InclConstructor - s := s + {constructor}.
+*)
+
+PROCEDURE InclConstructor (s: StateCheck) ;
+
+
+(*
+   ExclVar - s := s + {var}.
+*)
+
+PROCEDURE ExclVar (s: StateCheck) ;
+
+
+(*
+   ExclConst - s := s + {const}.
+*)
+
+PROCEDURE ExclConst (s: StateCheck) ;
+
+
+(*
+   ExclType - s := s + {type}.
+*)
+
+PROCEDURE ExclType (s: StateCheck) ;
+
+
+(*
+   ExclConstFunc - s := s + {constfunc}.
+*)
+
+PROCEDURE ExclConstFunc (s: StateCheck) ;
+
+
+(*
+   ExclVarParam - s := s + {varparam}.
+*)
+
+PROCEDURE ExclVarParam (s: StateCheck) ;
+
+
+(*
+   ExclConstructor - s := s - {varparam}.
+*)
+
+PROCEDURE ExclConstructor (s: StateCheck) ;
+
+
+(*
+   CheckQualident - checks to see that qualident sym is allowed in the state s.
+*)
+
+PROCEDURE CheckQualident (tok: CARDINAL; s: StateCheck; sym: CARDINAL) ;
+
+
+END M2StateCheck.
diff --git a/gcc/m2/gm2-compiler/M2StateCheck.mod b/gcc/m2/gm2-compiler/M2StateCheck.mod
new file mode 100644
index 0000000..e53cb17
--- /dev/null
+++ b/gcc/m2/gm2-compiler/M2StateCheck.mod
@@ -0,0 +1,344 @@
+(* M2StateCheck.mod provide state check tracking for declarations.
+
+Copyright (C) 2024 Free Software Foundation, Inc.
+Contributed by Gaius Mulley <gaiusmod2@gmail.com>.
+
+This file is part of GNU Modula-2.
+
+GNU Modula-2 is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 3, or (at your option)
+any later version.
+
+GNU Modula-2 is distributed in the hope that it will be useful, but
+WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with GNU Modula-2; see the file COPYING3.  If not see
+<http://www.gnu.org/licenses/>.  *)
+
+IMPLEMENTATION MODULE M2StateCheck ;
+
+FROM Storage IMPORT ALLOCATE ;
+FROM M2MetaError IMPORT MetaErrorStringT1 ;
+FROM DynamicStrings IMPORT String, InitString, ConCat, Mark ;
+FROM SymbolTable IMPORT NulSym, IsType, IsVar, IsConst ;
+
+
+TYPE
+   StateCheck = POINTER TO RECORD
+                              state: StateSet ;
+                              stack,
+                              next : StateCheck ;
+                           END ;
+
+   State = (const, var, type, constfunc, varparam, constructor) ;
+
+   StateSet = SET OF State ;
+
+VAR
+   FreeList: StateCheck ;
+
+
+(*
+   InitState - returns a new initialized StateCheck.
+*)
+
+PROCEDURE InitState () : StateCheck ;
+VAR
+   s: StateCheck ;
+BEGIN
+   s := New () ;
+   WITH s^ DO
+      state := StateSet {} ;
+      stack := NIL ;
+      next := NIL
+   END ;
+   RETURN s
+END InitState ;
+
+
+(*
+   New - returns an uninitialized StateCheck.
+*)
+
+PROCEDURE New () : StateCheck ;
+VAR
+   s: StateCheck ;
+BEGIN
+   IF FreeList = NIL
+   THEN
+      NEW (s)
+   ELSE
+      s := FreeList ;
+      FreeList := FreeList^.next
+   END ;
+   RETURN s
+END New ;
+
+
+(*
+   PushState - duplicates the StateCheck s and chains the new copy to s.
+               Return the copy.
+*)
+
+PROCEDURE PushState (VAR s: StateCheck) ;
+VAR
+   copy: StateCheck ;
+BEGIN
+   copy := InitState () ;
+   copy^.state := s^.state ;
+   copy^.stack := s ;
+   s := copy
+END PushState ;
+
+
+(*
+   KillState - destructor for StateCheck.
+*)
+
+PROCEDURE KillState (VAR s: StateCheck) ;
+VAR
+   t: StateCheck ;
+BEGIN
+   WHILE s^.stack # NIL DO
+      t := s^.stack ;
+      s^.stack := t^.stack ;
+      Dispose (t)
+   END ;
+   Dispose (s)
+END KillState ;
+
+
+(*
+   Dispose - place s onto the FreeList and set s to NIL.
+*)
+
+PROCEDURE Dispose (VAR s: StateCheck) ;
+BEGIN
+   s^.next := FreeList ;
+   FreeList := s
+END Dispose ;
+
+
+(*
+   InclVar - s := s + {var}.
+*)
+
+PROCEDURE InclVar (s: StateCheck) ;
+BEGIN
+   INCL (s^.state, var)
+END InclVar ;
+
+
+(*
+   InclConst - s := s + {const}.
+*)
+
+PROCEDURE InclConst (s: StateCheck) ;
+BEGIN
+   INCL (s^.state, const)
+END InclConst ;
+
+
+(*
+   InclType - s := s + {type}.
+*)
+
+PROCEDURE InclType (s: StateCheck) ;
+BEGIN
+   INCL (s^.state, type)
+END InclType ;
+
+
+(*
+   InclConstFunc - s := s + {constfunc}.
+*)
+
+PROCEDURE InclConstFunc (s: StateCheck) ;
+BEGIN
+   INCL (s^.state, constfunc)
+END InclConstFunc ;
+
+
+(*
+   InclVarParam - s := s + {varparam}.
+*)
+
+PROCEDURE InclVarParam (s: StateCheck) ;
+BEGIN
+   INCL (s^.state, varparam)
+END InclVarParam ;
+
+
+(*
+   InclConstructor - s := s + {constructor}.
+*)
+
+PROCEDURE InclConstructor (s: StateCheck) ;
+BEGIN
+   INCL (s^.state, constructor)
+END InclConstructor ;
+
+
+(*
+   ExclVar - s := s - {var}.
+*)
+
+PROCEDURE ExclVar (s: StateCheck) ;
+BEGIN
+   EXCL (s^.state, var)
+END ExclVar ;
+
+
+(*
+   ExclConst - s := s - {const}.
+*)
+
+PROCEDURE ExclConst (s: StateCheck) ;
+BEGIN
+   EXCL (s^.state, const)
+END ExclConst ;
+
+
+(*
+   ExclType - s := s - {type}.
+*)
+
+PROCEDURE ExclType (s: StateCheck) ;
+BEGIN
+   EXCL (s^.state, type)
+END ExclType ;
+
+
+(*
+   ExclConstFunc - s := s - {constfunc}.
+*)
+
+PROCEDURE ExclConstFunc (s: StateCheck) ;
+BEGIN
+   EXCL (s^.state, constfunc)
+END ExclConstFunc ;
+
+
+(*
+   ExclVarParam - s := s - {varparam}.
+*)
+
+PROCEDURE ExclVarParam (s: StateCheck) ;
+BEGIN
+   EXCL (s^.state, varparam)
+END ExclVarParam ;
+
+
+(*
+   ExclConstructor - s := s - {varparam}.
+*)
+
+PROCEDURE ExclConstructor (s: StateCheck) ;
+BEGIN
+   EXCL (s^.state, constructor)
+END ExclConstructor ;
+
+
+(*
+   PopState - pops the current state.
+*)
+
+PROCEDURE PopState (VAR s: StateCheck) ;
+VAR
+   t: StateCheck ;
+BEGIN
+   t := s ;
+   s := s^.stack ;
+   t^.stack := NIL ;
+   Dispose (t)
+END PopState ;
+
+
+(*
+   CheckQualident - checks to see that qualident sym is allowed in the state s.
+*)
+
+PROCEDURE CheckQualident (tok: CARDINAL; s: StateCheck; sym: CARDINAL) ;
+BEGIN
+   IF sym = NulSym
+   THEN
+      (* Ignore.  *)
+   ELSIF IsType (sym)
+   THEN
+      IF (constfunc IN s^.state) OR (constructor IN s^.state)
+      THEN
+         (* Ok.  *)
+      ELSIF const IN s^.state
+      THEN
+         GenerateError (tok, s, sym)
+      END
+   ELSIF IsConst (sym)
+   THEN
+      IF (constfunc IN s^.state) OR (constructor IN s^.state)
+      THEN
+         (* Ok.  *)
+      ELSIF (var IN s^.state) OR (type IN s^.state)
+      THEN
+         GenerateError (tok, s, sym)
+      END
+   ELSIF IsVar (sym)
+   THEN
+      IF constfunc IN s^.state
+      THEN
+         (* Ok.  *)
+      ELSIF (const IN s^.state) OR (type IN s^.state) OR (var IN s^.state)
+      THEN
+         GenerateError (tok, s, sym)
+      END
+   END
+END CheckQualident ;
+
+
+(*
+   GenerateError - generates an unrecoverable error string based on the state and sym.
+*)
+
+PROCEDURE GenerateError (tok: CARDINAL; s: StateCheck; sym: CARDINAL) ;
+VAR
+   str: String ;
+BEGIN
+   str := InitString ('not expecting a {%1Ad} {%1a: }in a ') ;
+   IF const IN s^.state
+   THEN
+      str := ConCat (str, Mark (InitString ('{%kCONST} block')))
+   ELSIF type IN s^.state
+   THEN
+      str := ConCat (str, Mark (InitString ('{%kTYPE} block')))
+   ELSIF var IN s^.state
+   THEN
+      str := ConCat (str, Mark (InitString ('{%kVAR} block')))
+   END ;
+   IF constfunc IN s^.state
+   THEN
+      str := ConCat (str, Mark (InitString (' and within a constant procedure function actual parameter')))
+   END ;
+   IF constructor IN s^.state
+   THEN
+      str := ConCat (str, Mark (InitString (' and within a constructor')))
+   END ;
+   MetaErrorStringT1 (tok, str, sym)
+END GenerateError ;
+
+
+(*
+   init - initialize the global variables in the module.
+*)
+
+PROCEDURE init ;
+BEGIN
+   FreeList := NIL
+END init ;
+
+
+BEGIN
+   init
+END M2StateCheck.
diff --git a/gcc/m2/gm2-compiler/P3Build.bnf b/gcc/m2/gm2-compiler/P3Build.bnf
index 0cec329..f48b508 100644
--- a/gcc/m2/gm2-compiler/P3Build.bnf
+++ b/gcc/m2/gm2-compiler/P3Build.bnf
@@ -132,6 +132,7 @@ FROM M2Quads IMPORT PushT, PopT, PushTF, PopTF, PopNothing, Annotate,
                     PushInConstExpression, PopInConstExpression,
                     PushInConstParameters, PopInConstParameters, IsInConstParameters,
                     BuildDefaultFieldAlignment, BuildPragmaField,
+                    OperandT, OperandTok,
                     IsAutoPushOn, PushAutoOff, PushAutoOn, PopAuto ;
 
 FROM P3SymBuild IMPORT P3StartBuildProgModule,
@@ -177,6 +178,14 @@ FROM M2Batch IMPORT IsModuleKnown ;
 
 FROM M2CaseList IMPORT BeginCaseList, EndCaseList ;
 
+FROM M2StateCheck IMPORT StateCheck,
+                         InitState, PushState, PopState,
+                         InclConst, ExclConst,
+                         InclType, ExclType,
+                         InclVar, ExclVar,
+                         InclConstructor, ExclConstructor,
+                         InclConstFunc, CheckQualident ;
+
 IMPORT M2Error ;
 
 CONST
@@ -184,19 +193,20 @@ CONST
    DebugAsm  = FALSE ;
 
 VAR
-   WasNoError: BOOLEAN ;
+   seenError : BOOLEAN ;
+   BlockState: StateCheck ;
 
 
 PROCEDURE ErrorString (s: String) ;
 BEGIN
-   ErrorStringAt(s, GetTokenNo ()) ;
-   WasNoError := FALSE
+   ErrorStringAt (s, GetTokenNo ()) ;
+   seenError := TRUE
 END ErrorString ;
 
 
 PROCEDURE ErrorArray (a: ARRAY OF CHAR) ;
 BEGIN
-   ErrorString(InitString(a))
+   ErrorString (InitString (a))
 END ErrorArray ;
 
 
@@ -391,9 +401,9 @@ END Expect ;
 
 PROCEDURE CompilationUnit () : BOOLEAN ;
 BEGIN
-   WasNoError := TRUE ;
+   seenError := FALSE ;
    FileUnit(SetOfStop0{eoftok}, SetOfStop1{}, SetOfStop2{}) ;
-   RETURN( WasNoError )
+   RETURN NOT seenError
 END CompilationUnit ;
 
 
@@ -457,6 +467,8 @@ BEGIN
 END Real ;
 
 % module P3Build end
+BEGIN
+   BlockState := InitState ()
 END P3Build.
 % rules
 error       'ErrorArray' 'ErrorString'
@@ -662,12 +674,25 @@ Qualident :=                                                               % VAR
              { "." Ident }                                                 % END %
            =:
 
+
+QualidentCheck :=                                                          % PushAutoOn %
+                  Qualident
+                                                                           % PopAuto %
+                                                                           % CheckQualident (OperandTok (1), BlockState, OperandT (1)) %
+                                                                           % IF NOT IsAutoPushOn ()
+                                                                             THEN
+                                                                                PopNothing
+                                                                             END %
+                =:
+
 ConstantDeclaration :=                                                     % VAR tokno: CARDINAL ; %
+                                                                           % InclConst (BlockState) %
                                                                            % PushAutoOn %
                        ( Ident "="                                         % tokno := GetTokenNo () -1 %
                                                                            % BuildConst %
                          ConstExpression )                                 % BuildAssignConstant (tokno) %
                                                                            % PopAuto %
+                                                                           % ExclConst (BlockState) %
                      =:
 
 ConstExpression :=                                                         % VAR tokpos: CARDINAL ; %
@@ -764,10 +789,14 @@ ArraySetRecordValue := ComponentValue                                      % Bui
 
 Constructor :=                                                             % VAR tokpos: CARDINAL ; %
                                                                            % DisplayStack %
+                                                                           % InclConstructor (BlockState) %
+                                                                           % CheckQualident (OperandTok (1), BlockState, OperandT (1)) %
                '{'                                                         % tokpos := GetTokenNo () -1 %
                                                                            % BuildConstructorStart (tokpos) %
                   [ ArraySetRecordValue ]                                  % BuildConstructorEnd (tokpos, GetTokenNo())  %
-               '}' =:
+               '}'
+                                                                           % ExclConstructor (BlockState) %
+             =:
 
 ConstSetOrQualidentOrFunction :=                                           % VAR tokpos: CARDINAL ; %
                                                                            % tokpos := GetTokenNo () %
@@ -779,8 +808,12 @@ ConstSetOrQualidentOrFunction :=                                           % VAR
                                      Constructor
                                  ) =:
 
-ConstActualParameters :=                                                   % PushInConstParameters %
+ConstActualParameters :=                                                   % PushState (BlockState) %
+                                                                           % InclConstFunc (BlockState) %
+                                                                           % CheckQualident (OperandTok (1), BlockState, OperandT (1)) %
+                                                                           % PushInConstParameters %
                          ActualParameters                                  % PopInConstParameters %
+                                                                           % PopState (BlockState) %
                        =:
 
 ConstAttribute := "__ATTRIBUTE__" "__BUILTIN__" "(" "("                    % PushAutoOn %
@@ -802,7 +835,9 @@ ByteAlignment :=                                                           % VAR
 
 Alignment := [ ByteAlignment ] =:
 
-TypeDeclaration := Ident "=" Type Alignment
+TypeDeclaration :=                                                         % InclType (BlockState) %
+                   Ident "=" Type Alignment
+                                                                           % ExclType (BlockState) %
                 =:
 
 Type :=
@@ -814,7 +849,7 @@ Type :=
           | ProcedureType )                                                % PopAuto %
       =:
 
-SimpleType := Qualident [ SubrangeType ] | Enumeration | SubrangeType =:
+SimpleType := QualidentCheck [ SubrangeType ] | Enumeration | SubrangeType =:
 
 Enumeration := "("
                    ( IdentList
@@ -900,7 +935,7 @@ FieldList := IdentList ":"
 
 TagIdent := [ Ident ] =:
 
-CaseTag :=  TagIdent [":" Qualident ] =:
+CaseTag :=  TagIdent [":" QualidentCheck ] =:
 
 Varient := [                                                               % BeginVarientList %
              VarientCaseLabelList ":" FieldListSequence                    % EndVarientList %
@@ -980,7 +1015,7 @@ FormalTypeList := "(" ( ")" FormalReturn |
 
 FormalReturn := [ ":" OptReturnType ] =:
 
-OptReturnType := "[" Qualident "]" | Qualident =:
+OptReturnType := "[" QualidentCheck "]" | QualidentCheck =:
 
 ProcedureParameters := ProcedureParameter
                        { "," ProcedureParameter } =:
@@ -1027,10 +1062,12 @@ VarIdentList := VarIdent                                                   % VAR
              =:
 
 VariableDeclaration := VarIdentList ":"
+                                                                           % InclVar (BlockState) %
                        Type Alignment
+                                                                           % ExclVar (BlockState) %
                     =:
 
-Designator := Qualident                                                    % CheckWithReference %
+Designator := QualidentCheck                                               % CheckWithReference %
               { SubDesignator } =:
 
 SubDesignator := "."                                                       % VAR Sym, Type, tok,
@@ -1419,7 +1456,7 @@ OptArg := "[" Ident ":" FormalType [ "=" ConstExpression                   % Bui
 DefOptArg := "[" Ident ":" FormalType "=" ConstExpression                  % BuildOptArgInitializer %
                                                           "]" =:
 
-FormalType := { "ARRAY" "OF" } Qualident =:
+FormalType := { "ARRAY" "OF" } QualidentCheck =:
 
 ModuleDeclaration :=                                                       % VAR modulet: CARDINAL ; %
                                                                            % modulet := GetTokenNo () %
diff --git a/gcc/m2/gm2-compiler/PCBuild.bnf b/gcc/m2/gm2-compiler/PCBuild.bnf
index 0e45b2e..6e263b0 100644
--- a/gcc/m2/gm2-compiler/PCBuild.bnf
+++ b/gcc/m2/gm2-compiler/PCBuild.bnf
@@ -61,7 +61,8 @@ FROM M2Reserved IMPORT tokToTok, toktype,
                        OrTok, TimesTok, DivTok, DivideTok, ModTok, RemTok,
                        AndTok, AmbersandTok, PeriodPeriodTok, ByTok ;
 
-FROM M2Quads IMPORT Top, PushT, PopT, PushTF, PopTF, PopNothing, OperandT, PushTFA,
+FROM M2Quads IMPORT Top, PushT, PopT, PushTF, PopTF, PopNothing, OperandT, OperandTok,
+                    PushTFA,
                     PushTFn, PopTFn, PushTFtok, PopTtok, PopTFtok, PushTtok, PushTFntok,
                     PushT, PushTF, IsAutoPushOn, PushAutoOff, PushAutoOn, PopAuto,
                     BuildTypeForConstructor, BuildConstructor, BuildConstructorEnd,
@@ -120,6 +121,11 @@ FROM SymbolTable IMPORT MakeGnuAsm, PutGnuAsmVolatile, PutGnuAsm, PutGnuAsmInput
 
 FROM M2Batch IMPORT IsModuleKnown ;
 
+FROM M2StateCheck IMPORT StateCheck,
+                         InitState, PushState, PopState, InclConst, ExclConst,
+                         InclConstructor, ExclConstructor,
+                         InclConstFunc, CheckQualident ;
+
 IMPORT M2Error ;
 
 
@@ -128,9 +134,8 @@ CONST
    Pass1     = FALSE ;
 
 VAR
-   InConstParameter,
-   InConstBlock,
-   seenError       : BOOLEAN ;
+   BlockState: StateCheck ;
+   seenError : BOOLEAN ;
 
 
 PROCEDURE ErrorString (s: String) ;
@@ -407,8 +412,7 @@ END Real ;
 
 % module PCBuild end
 BEGIN
-   InConstParameter := FALSE ;
-   InConstBlock := FALSE
+   BlockState := InitState ()
 END PCBuild.
 % rules
 error       'ErrorArray' 'ErrorString'
@@ -597,7 +601,7 @@ Qualident :=                                                               % VAR
            =:
 
 ConstantDeclaration :=                                                     % VAR top: CARDINAL ; %
-                                                                           % InConstBlock := TRUE %
+                                                                           % InclConst (BlockState) %
                                                                            % top := Top() %
                                                                            % PushAutoOn %
                        ( Ident "="                                         % StartDesConst %
@@ -607,7 +611,7 @@ ConstantDeclaration :=                                                     % VAR
                                                                            % EndDesConst %
                                                                            % PopAuto %
                                                                            % Assert(top=Top()) %
-                                                                           % InConstBlock := FALSE %
+                                                                           % ExclConst (BlockState) %
                      =:
 
 ConstExpression :=                                                         % VAR top: CARDINAL ; %
@@ -697,11 +701,14 @@ ComponentValue := ComponentElement [ 'BY' ConstExpression ] =:
 ArraySetRecordValue := ComponentValue { ','                                % NextConstructorField %
                                             ComponentValue } =:
 
-Constructor := '{'                                                         % PushConstructorCastType %
+Constructor := '{'                                                         % InclConstructor (BlockState) %
+                                                                           % CheckQualident (OperandTok (1), BlockState, OperandT (1)) %
+                                                                           % PushConstructorCastType %
                                                                            % PushInConstructor %
                                                                            % BuildConstructor (GetTokenNo ()-1) %
                   [ ArraySetRecordValue ]                                  % PopConstructor %
                '}'                                                         % PopInConstructor %
+                                                                           % ExclConstructor (BlockState) %
                    =:
 
 ConstructorOrConstActualParameters := Constructor | ConstActualParameters  % PushConstFunctionType %
@@ -714,23 +721,21 @@ ConstSetOrQualidentOrFunction :=                                           % Pus
                                                                            % VAR tokpos: CARDINAL ; %
                                                                            % tokpos := GetTokenNo () %
                                  (
-                                   PushQualident                           % IF (NOT InConstParameter) AND InConstBlock
-                                                                             THEN
-                                                                                CheckNotVar (tokpos)
-                                                                             END %
-                                   ( ConstructorOrConstActualParameters |  % PushConstType %
+                                   PushQualident
+                                   ( ConstructorOrConstActualParameters |  % CheckQualident (OperandTok (1), BlockState, OperandT (1)) %
+                                                                           % PushConstType %
                                                                            % PopNothing %
                                                                           )
                                    |                                       % BuildTypeForConstructor (tokpos) %
                                      Constructor )                         % PopAuto %
                                =:
 
-ConstActualParameters :=                                                   % VAR oldConstParameter: BOOLEAN ; %
-                                                                           % oldConstParameter := InConstParameter %
-                                                                           % InConstParameter := TRUE %
+ConstActualParameters :=                                                   % PushState (BlockState) %
+                                                                           % InclConstFunc (BlockState) %
+                                                                           % CheckQualident (OperandTok (1), BlockState, OperandT (1)) %
                                                                            % PushT(0) %
                          "(" [ ConstExpList ] ")"
-                                                                           % InConstParameter := oldConstParameter %
+                                                                           % PopState (BlockState) %
                          =:
 
 ConstExpList :=                                                            % VAR n: CARDINAL ; %
@@ -1023,9 +1028,9 @@ ConstructorOrSimpleDes := Constructor |                                    % Pop
                                           SimpleDes [ ActualParameters ]
                         =:
 
-SetOrDesignatorOrFunction :=                                              % PushAutoOff %
-                                                                          % VAR tokpos: CARDINAL ; %
+SetOrDesignatorOrFunction :=                                              % VAR tokpos: CARDINAL ; %
                                                                           % tokpos := GetTokenNo () %
+                                                                          % PushAutoOff %
                              (
                                PushQualident
                                ( ConstructorOrSimpleDes |                 % PopNothing %
diff --git a/gcc/m2/gm2-gcc/init.cc b/gcc/m2/gm2-gcc/init.cc
index 17ca918..de9fb99 100644
--- a/gcc/m2/gm2-gcc/init.cc
+++ b/gcc/m2/gm2-gcc/init.cc
@@ -105,6 +105,8 @@ EXTERN void _M2_ldtoa_init (int argc, char *argv[], char *envp[]);
 EXTERN void _M2_M2Check_init (int argc, char *argv[], char *envp[]);
 EXTERN void _M2_M2SSA_init (int argc, char *argv[], char *envp[]);
 EXTERN void _M2_M2SymInit_init (int argc, char *argv[], char *envp[]);
+EXTERN void _M2_M2StateCheck_init (int argc, char *argv[], char *envp[]);
+EXTERN void _M2_P3Build_init (int argc, char *argv[], char *envp[]);
 EXTERN void exit (int);
 EXTERN void M2Comp_compile (const char *filename);
 EXTERN void RTExceptions_DefaultErrorCatch (void);
@@ -200,5 +202,7 @@ init_PerCompilationInit (const char *filename)
   _M2_M2SymInit_init (0, NULL, NULL);
   _M2_M2Check_init (0, NULL, NULL);
   _M2_M2LangDump_init (0, NULL, NULL);
+  _M2_M2StateCheck_init (0, NULL, NULL);
+  _M2_P3Build_init (0, NULL, NULL);
   M2Comp_compile (filename);
 }
diff --git a/gcc/testsuite/gm2/errors/fail/array1.mod b/gcc/testsuite/gm2/errors/fail/array1.mod
index 274011b..221b32e 100644
--- a/gcc/testsuite/gm2/errors/fail/array1.mod
+++ b/gcc/testsuite/gm2/errors/fail/array1.mod
@@ -17,9 +17,14 @@ Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. *)
 
 MODULE array1 ;
 
+PROCEDURE init ;
 VAR
    a: ARRAY [FALSE..TRUE] OF CARDINAL ;
    i, j: CARDINAL ;
 BEGIN
    a[i=j] := j
+END init ;
+
+BEGIN
+   init
 END array1.
diff --git a/gcc/testsuite/gm2/errors/fail/badtype.mod b/gcc/testsuite/gm2/errors/fail/badtype.mod
new file mode 100644
index 0000000..32ac3a6
--- /dev/null
+++ b/gcc/testsuite/gm2/errors/fail/badtype.mod
@@ -0,0 +1,10 @@
+MODULE badtype ;
+
+PROCEDURE bar (VAR a: CARDINAL) ;
+TYPE
+   Foo = a ;
+BEGIN
+END bar ;
+
+BEGIN
+END badtype.
diff --git a/gcc/testsuite/gm2/errors/fail/badvar.mod b/gcc/testsuite/gm2/errors/fail/badvar.mod
new file mode 100644
index 0000000..2d67cb6
--- /dev/null
+++ b/gcc/testsuite/gm2/errors/fail/badvar.mod
@@ -0,0 +1,10 @@
+MODULE badvar ;
+
+PROCEDURE bar (VAR a: CARDINAL) ;
+VAR
+   Foo: a ;
+BEGIN
+END bar ;
+
+BEGIN
+END badvar.
diff --git a/gcc/testsuite/gm2/errors/fail/errors-fail.exp b/gcc/testsuite/gm2/errors/fail/errors-fail.exp
index 8af0e72..a8fbd2c 100644
--- a/gcc/testsuite/gm2/errors/fail/errors-fail.exp
+++ b/gcc/testsuite/gm2/errors/fail/errors-fail.exp
@@ -25,7 +25,7 @@ if $tracelevel then {
 # load support procs
 load_lib gm2-torture.exp
 
-gm2_init_pim "${srcdir}/gm2/errors/fail" -Wpedantic -Wstudents -Wunused-variable
+gm2_init_iso "${srcdir}/gm2/errors/fail" -Wpedantic -Wunused-variable -Wuninit-variable-checking=all
 
 foreach testcase [lsort [glob -nocomplain $srcdir/$subdir/*.mod]] {
     # If we're only testing specific files and this isn't one of them, skip it.
diff --git a/gcc/testsuite/gm2/errors/fail/testfio.mod b/gcc/testsuite/gm2/errors/fail/testfio.mod
index fabf93e..f11e09e 100644
--- a/gcc/testsuite/gm2/errors/fail/testfio.mod
+++ b/gcc/testsuite/gm2/errors/fail/testfio.mod
@@ -22,12 +22,16 @@ FROM StdIO IMPORT Write ;
 FROM StrIO IMPORT WriteString, WriteLn ;
 FROM FIO IMPORT Exists, OpenToRead, Close, File, IsNoError, EOF, ReadChar ;
 
+PROCEDURE init ;
 VAR
    i: INTEGER ;
    f: File ;
    c: CARDINAL ;
    a: ARRAY [0..20] OF CHAR ;
 BEGIN
+   IF f = 0
+   THEN
+   END ;
    WriteString('testfio starting') ; WriteLn ;
    c := 1 ;
    WHILE GetArg(a, c) DO
@@ -45,4 +49,8 @@ BEGIN
       END ;
       INC(c)
    END
+END init ;
+
+BEGIN
+   init
 END testfio.
diff --git a/gcc/testsuite/gm2/errors/fail/testparam.mod b/gcc/testsuite/gm2/errors/fail/testparam.mod
index 238334f..142a251 100644
--- a/gcc/testsuite/gm2/errors/fail/testparam.mod
+++ b/gcc/testsuite/gm2/errors/fail/testparam.mod
@@ -19,10 +19,15 @@ MODULE testparam ;
 
 FROM FIO IMPORT IsNoError, Close, EOF ;
 
+PROCEDURE init ;
 VAR
    i: INTEGER ;
 BEGIN
    IF EOF(i)
    THEN
    END
+END init ;
+
+BEGIN
+   init
 END testparam.