[PATCH] PR modula2/120389 Assigning wrong type to an array causes an ICE

[PATCH] PR modula2/120389 Assigning wrong type to an array causes an ICE

Although cherry picked as described.  The cherry pick does not include
the command option (-fm2-strict-type-reason) introduced in:
gcc/m2/gm2-lang.cc, gcc/m2/lang.opt and gcc/doc/gm2.texi from the
original patch.

This patch provides follow on fixes for undetected type violations
which can occur then Lvalues are generated during assignment.
For example array accesses and with statements.  The type checker
M2Check.mod has been overhauled and cleaned up.

gcc/m2/ChangeLog:

	PR modula2/120389
	* gm2-compiler/M2Check.def (AssignmentTypeCompatible): Add new
	parameter enableReason.
	* gm2-compiler/M2Check.mod (EquivalenceProcedure): New type.
	(falseReason2): New procedure function.
	(falseReason1): Ditto.
	(falseReason0): Ditto.
	(checkTypeEquivalence): Rewrite.
	(checkUnboundedArray): Ditto.
	(checkUnbounded): Ditto.
	(checkArrayTypeEquivalence): Ditto.
	(checkCharStringTypeEquivalence): Ditto.
	(buildError4): Add false reason.
	(buildError2): Ditto.
	(IsTyped): Use GetDType.
	(IsTypeEquivalence): New procedure function.
	(checkVarTypeEquivalence): Ditto.
	(checkVarEquivalence ): Rewrite.
	(checkConstMeta): Ditto.
	(checkEnumField): New procedure function.
	(checkEnumFieldEquivalence): Ditto.
	(checkSubrangeTypeEquivalence): Rewrite.
	(checkSystemEquivalence): Ditto.
	(checkTypeKindViolation): Ditto.
	(doCheckPair): Ditto.
	(InitEquivalenceArray): New procedure.
	(addEquivalence): Ditto.
	(checkProcType): Rewrite.
	(deconstruct): Deallocate reason string.
	(AssignmentTypeCompatible): Initialize reason and reasonEnable
	fields.
	(ParameterTypeCompatible): Ditto.
	(doExpressionTypeCompatible): Ditto.
	* gm2-compiler/M2GenGCC.mod (CodeIndrX) Rewrite.
	(CheckBinaryExpressionTypes): Rewrite and simplify now that the
	type checker is more robust.
	(CheckElementSetTypes): Ditto.
	(CodeXIndr): Add new range assignment type check.
	* gm2-compiler/M2MetaError.def: Correct comments.
	* gm2-compiler/M2Options.def (SetStrictTypeAssignment): New procedure.
	(SetStrictTypeReason): Ditto.
	* gm2-compiler/M2Options.mod: (SetStrictTypeAssignment): New procedure.
	(SetStrictTypeReason): Ditto.
	(StrictTypeReason): Initialize.
	(StrictTypeAssignment): Ditto.
	* gm2-compiler/M2Quads.mod (CheckBreak): Delete.
	(BreakQuad): New global variable.
	(BreakAtQuad): Delete.
	(gdbhook): New procedure.
	(BreakWhenQuadCreated): Ditto.
	(CheckBreak): Ditto.
	(Init): Call BreakWhenQuadCreated and gdbhook.
	(doBuildAssignment): Add type assignment range check.
	(CheckProcTypeAndProcedure): Only check if the procedure
	types differ.
	(doIndrX): Add type IndrX range check.
	(CheckReturnType): Add range return type check.
	* gm2-compiler/M2Range.def (InitTypesIndrXCheck): New procedure
	function.
	(InitTypesReturnTypeCheck): Ditto.
	* gm2-compiler/M2Range.mod (InitTypesIndrXCheck): New procedure
	function.
	(InitTypesReturnTypeCheck): Ditto.
	(HandlerExists): Add new clauses.
	(FoldAssignment): Pass extra FALSE parameter to
	AssignmentTypeCompatible.
	(FoldTypeReturnFunc): New procedure.
	(FoldTypeAssign): Ditto.
	(FoldTypeIndrX): Ditto.
	(CodeTypeAssign): Rewrite.
	(CodeTypeIndrX): New procedure.
	(CodeTypeReturnFunc): Ditto.
	(FoldTypeCheck): Add new case clauses.
	(CodeTypeCheck): Ditto.
	(FoldRangeCheckLower): Ditto.
	(IssueWarning): Ditto.
	* gm2-gcc/m2options.h (M2Options_SetStrictTypeAssignment): New
	function prototype.
	(M2Options_SetStrictTypeReason): Ditto.

gcc/testsuite/ChangeLog:

	PR modula2/120389
	* gm2/pim/fail/testcharint.mod: New test.
	* gm2/pim/fail/testindrx.mod: New test.
	* gm2/pim/pass/testxindr.mod: New test.
	* gm2/pim/pass/testxindr2.mod: New test.
	* gm2/pim/pass/testxindr3.mod: New test.

(cherry picked from commit e131ba3de5f487f5e957ba1b011c960fce557c7b)

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