* complain about turned off support of c style operators only in the parser,

    so error recovery is better

compiler/msg/errore.msg

@@ -1671,9 +1671,12 @@ parser_e_suspending_externals_not_supported_on_current_platform=03368_E_Declarin
 parser_w_widechar_set_reduced=03369_W_Reducing Widechar set to single-byte AnsiChar set.
 % The base type of a set can only have 255 elements. Sets of wide characters
 % are reduced to sets of 1-byte characters.
-parser_e_nostringaliasinsystem=03370_e_Using 'string' alias is not allowed in the system unit. Use short-,ansi- or unicodestring.
+parser_e_nostringaliasinsystem=03370_E_Using 'string' alias is not allowed in the system unit. Use short-,ansi- or unicodestring.
 % As a safeguard, the system unit may only use basic string types, not the
 % string alias which is dependent on the mode in which a unit is compiled.
+parser_e_coperators_off=03371_E_C styled assignment operators are turned off
+% By default, c style assignment operators (+=, -=, *=, /=) are turn off. Either turn them on by the command line
+% parameter -Sc or in the source code by {$COPERATORS ON}
 %
 % \end{description}
 %

compiler/msgidx.inc

@@ -490,6 +490,7 @@ const
   parser_e_suspending_externals_not_supported_on_current_platform=03368;
   parser_w_widechar_set_reduced=03369;
   parser_e_nostringaliasinsystem=03370;
+  parser_e_coperators_off=03371;
   type_e_mismatch=04000;
   type_e_incompatible_types=04001;
   type_e_not_equal_types=04002;
@@ -1177,9 +1178,9 @@ const
   option_info=11024;
   option_help_pages=11025;
 
-  MsgTxtSize = 92723;
+  MsgTxtSize = 92776;
 
   MsgIdxMax : array[1..20] of longint=(
-    29,114,371,134,102,63,148,38,224,71,
+    29,114,372,134,102,63,148,38,224,71,
     69,20,30,1,1,1,1,1,1,1
   );

compiler/pexpr.pas

@@ -4952,24 +4952,32 @@ implementation
              end;
            _PLUSASN :
              begin
+               if not(cs_support_c_operators in current_settings.moduleswitches) then
+                 Message(parser_e_coperators_off);
                consume(_PLUSASN);
                p2:=sub_expr(opcompare,[ef_accept_equal],nil);
                p1:=gen_c_style_operator(addn,p1,p2);
             end;
           _MINUSASN :
             begin
+               if not(cs_support_c_operators in current_settings.moduleswitches) then
+                 Message(parser_e_coperators_off);
                consume(_MINUSASN);
                p2:=sub_expr(opcompare,[ef_accept_equal],nil);
                p1:=gen_c_style_operator(subn,p1,p2);
             end;
           _STARASN :
             begin
+               if not(cs_support_c_operators in current_settings.moduleswitches) then
+                 Message(parser_e_coperators_off);
                consume(_STARASN  );
                p2:=sub_expr(opcompare,[ef_accept_equal],nil);
                p1:=gen_c_style_operator(muln,p1,p2);
             end;
           _SLASHASN :
             begin
+               if not(cs_support_c_operators in current_settings.moduleswitches) then
+                 Message(parser_e_coperators_off);
                consume(_SLASHASN  );
                p2:=sub_expr(opcompare,[ef_accept_equal],nil);
                p1:=gen_c_style_operator(slashn,p1,p2);

compiler/scanner.pas

@@ -5438,7 +5438,7 @@ type
              '+' :
                begin
                  readchar;
-                 if (c='=') and (cs_support_c_operators in current_settings.moduleswitches) then
+                 if c='=' then
                   begin
                     readchar;
                     token:=_PLUSASN;
@@ -5451,7 +5451,7 @@ type
              '-' :
                begin
                  readchar;
-                 if (c='=') and (cs_support_c_operators in current_settings.moduleswitches) then
+                 if c='=' then
                   begin
                     readchar;
                     token:=_MINUSASN;
@@ -5477,7 +5477,7 @@ type
              '*' :
                begin
                  readchar;
-                 if (c='=') and (cs_support_c_operators in current_settings.moduleswitches) then
+                 if c='=' then
                   begin
                     readchar;
                     token:=_STARASN;
@@ -5499,12 +5499,9 @@ type
                  case c of
                    '=' :
                      begin
-                       if (cs_support_c_operators in current_settings.moduleswitches) then
-                        begin
-                          readchar;
-                          token:=_SLASHASN;
-                          goto exit_label;
-                        end;
+                       readchar;
+                       token:=_SLASHASN;
+                       goto exit_label;
                      end;
                    '/' :
                      begin

tests/test/tcop1.pp

@@ -0,0 +1,20 @@
+{ test c style assignment operators }
+
+{$COPERATORS ON}
+var
+  i : Single;
+begin
+  i:=1234;
+  i += 1;
+  if i<>1235 then
+    halt(1);
+  i -= 1;
+  if i<>1234 then
+    halt(2);
+  i *= 2;
+  if i<>2468 then
+    halt(3);
+  i /= 2;
+  if i<>1234 then
+    halt(4);
+end.

tests/test/tcop2.pp

@@ -0,0 +1,11 @@
+{ %fail }
+{ test c style assignment operators }
+
+{$COPERATORS OFF}
+
+var
+  i : Single;
+begin
+  i:=1234;
+  i += 1;
+end.

tests/test/tcop3.pp

@@ -0,0 +1,11 @@
+{ %fail }
+{ test c style assignment operators }
+
+{$COPERATORS OFF}
+
+var
+  i : Single;
+begin
+  i:=1234;
+  i -= 1;
+end.

tests/test/tcop4.pp

@@ -0,0 +1,11 @@
+{ %fail }
+{ test c style assignment operators }
+
+{$COPERATORS OFF}
+
+var
+  i : Single;
+begin
+  i:=1234;
+  i *= 2;
+end.

tests/test/tcop5.pp

@@ -0,0 +1,11 @@
+{ %fail }
+{ test c style assignment operators }
+
+{$COPERATORS OFF}
+
+var
+  i : Single;
+begin
+  i:=1234;
+  i /= 2;
+end.