disallow GOTO when it could corrupt the estack

- this occurs inside a FOR or CASE statement
- GOTO out of a WHILE or REPEAT loop  works

pcomp/pcomp.pas

@@ -5813,6 +5813,19 @@ begin
 	matchToken(ColonToken);
 end;
 
+procedure parseGotoStatement;
+var aLabl: LablRef;
+begin
+	readNextToken;
+	matchToken(IdentToken);
+	aLabl := findLabel(curProcedure, lastToken.tokenText);
+	if aLabl = nil then
+		errorExit2('GOTO to undefined label', lastToken.tokenText);
+	if curProcedure^.estackCleanup > 0 then
+		errorExit2('GOTO not allowed inside FOR or CASE', '');
+	emitLabelJump(aLabl);
+end;
+
 procedure parseStatement;
 var sym: SymblRef;
 	cnst: ConstRef;
@@ -5838,13 +5851,7 @@ begin
 	end;
 
 	if checkToken(GotoToken) then
-	begin
-		readNextToken;
-		matchToken(IdentToken);
-		aLabl := findLabel(curProcedure, lastToken.tokenText);
-		if aLabl = nil then errorExit2('GOTO to undefined label', lastToken.tokenText);
-		emitLabelJump(aLabl);
-	end
+		parseGotoStatement
 	else
 	if checkToken(IfToken) then
 		parseIfStatement

tests/gototest.pas

@@ -0,0 +1,22 @@
+program gototest;
+var i:integer;
+label l1,l2;
+begin
+	goto l1;
+	writeln('skipped');
+	l1: writeln('goto destination 1');
+	{
+	for i := 1 to 10 do
+	begin
+		goto l2;
+	end;
+	}
+	{
+	case i of
+	1: writeln('1');
+	2: goto l2;
+	3..10: writeln('3 - 10');
+	end;
+	l2: writeln('goto destination 2');
+	}
+end.