patch 9.2.1015: Vim9: v:errmsg is set while looking ahead at a command

Problem:  In Vim9 script a line starting with a dict member is looked
          ahead at, to tell an assignment from an expression.  Where the
          expression runs on into the next line the lookahead cannot
          follow it, and what it makes of that reaches "v:errmsg" and
          whatever is being redirected, though nothing is wrong and the
          function compiles.
Solution: Turn error messages off around the lookahead instead of
          silencing them (Hirohito Higashi).

closes: #21168

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Signed-off-by: Hirohito Higashi <h.east.727@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>

src/ex_docmd.c

@@ -3848,7 +3848,7 @@ find_ex_command(
 		//	name[idx].member = val
 		//	etc.
 		eap->cmdidx = CMD_eval;
-		++emsg_silent;
+		++emsg_off;
 		if (skip_expr(&after, NULL) == OK)
 		{
 		    after = skipwhite(after);
@@ -3857,7 +3857,7 @@ find_ex_command(
 							   && after[2] == '='))
 			eap->cmdidx = CMD_var;
 		}
-		--emsg_silent;
+		--emsg_off;
 		return eap->cmd;
 	    }
 

src/testdir/test_vim9_cmd.vim

@@ -2251,4 +2251,21 @@ def Test_delfunction_dict_funcref()
   v9.CheckScriptSuccess(lines)
 enddef
 
+" Looking ahead at a line that starts with a dict member, to tell an
+" assignment from an expression, must not leave an error behind.
+def Test_no_error_from_looking_ahead()
+  var lines =<< trim END
+      vim9script
+      var d = {Fn: (m: string) => 0}
+      def F(b: bool)
+        d.Fn(b ? 'one'
+               : 'two')
+      enddef
+      v:errmsg = ''
+      defcompile
+      assert_equal('', v:errmsg)
+  END
+  v9.CheckScriptSuccess(lines)
+enddef
+
 " vim: ts=8 sw=2 sts=2 expandtab tw=80 fdm=marker

src/testdir/test_vim9_generics.vim

@@ -1211,7 +1211,7 @@ def Test_generic_obj_method()
     var a = A.new()
     a.Fn<>()
   END
-  v9.CheckSourceFailureList(lines, ["E1555: Empty type list specified for generic function '<>()'"])
+  v9.CheckSourceFailureList(lines, ["E1555: Empty type list specified for generic function 'Fn'"])
 
   lines =<< trim END
     vim9script
@@ -1295,7 +1295,7 @@ def Test_generic_obj_method_call_from_another_method()
     enddef
     defcompile
   END
-  v9.CheckSourceFailureList(lines, ["E1555: Empty type list specified for generic function '<>()'"])
+  v9.CheckSourceFailureList(lines, ["E1555: Empty type list specified for generic function 'Fn'"])
 
   lines =<< trim END
     vim9script
@@ -1476,7 +1476,7 @@ def Test_generic_class_method()
     endclass
     A.Fn<>()
   END
-  v9.CheckSourceFailureList(lines, ["E1555: Empty type list specified for generic function '<>()'"])
+  v9.CheckSourceFailureList(lines, ["E1555: Empty type list specified for generic function 'Fn'"])
 
   lines =<< trim END
     vim9script
@@ -1554,7 +1554,7 @@ def Test_generic_class_method_call_from_another_method()
     enddef
     defcompile
   END
-  v9.CheckSourceFailureList(lines, ["E1555: Empty type list specified for generic function '<>()'"])
+  v9.CheckSourceFailureList(lines, ["E1555: Empty type list specified for generic function 'Fn'"])
 
   lines =<< trim END
     vim9script

src/version.c

@@ -763,6 +763,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1015,
 /**/
     1014,
 /**/