patch 8.0.0663: unexpected error message only when 'verbose' is set

Problem:    Giving an error message only when 'verbose' set is unexpected.
Solution:   Give a warning message instead.

runtime/doc/eval.txt

@@ -1,4 +1,4 @@
-*eval.txt*	For Vim version 8.0.  Last change: 2017 Jun 22
+*eval.txt*	For Vim version 8.0.  Last change: 2017 Jun 23
 
 
 		  VIM REFERENCE MANUAL	  by Bram Moolenaar
@@ -8722,6 +8722,9 @@ See |:verbose-cmd| for more information.
 			not used an error message is given.  When [!] is used,
 			an existing function is silently replaced.  Unless it
 			is currently being executed, that is an error.
+			NOTE: Use ! wisely.  If used without care it can cause
+			an existing function to be replaced unexpectedly,
+			which is hard to debug.
 
 			For the {arguments} see |function-argument|.
 
@@ -8771,7 +8774,7 @@ See |:verbose-cmd| for more information.
 			implies that the effect of |:nohlsearch| is undone
 			when the function returns.
 
-				*:endf* *:endfunction* *E126* *E193* *E946*
+				*:endf* *:endfunction* *E126* *E193* *W22*
 :endf[unction] [argument]
 			The end of a function definition.  Best is to put it
 			on a line by its own, without [argument].
@@ -8780,12 +8783,16 @@ See |:verbose-cmd| for more information.
 				| command	command to execute next
 				\n command	command to execute next
 				" comment	always ignored
-				anything else	ignored, unless 'verbose' is
-						non-zero
+				anything else	ignored, warning given when
+						'verbose' is non-zero
 			The support for a following command was added in Vim
 			8.0.0654, before that any argument was silently
 			ignored.
 
+			To be able to define a function inside an `:execute`
+			command, use line breaks instead of |:bar|: >
+				:exe "func Foo()\necho 'foo'\nendfunc"
+<
 				*:delf* *:delfunction* *E130* *E131* *E933*
 :delf[unction][!] {name}
 			Delete function {name}.

src/message.c

@@ -3471,6 +3471,13 @@ give_warning(char_u *message, int hl)
     --no_wait_return;
 }
 
+    void
+give_warning2(char_u *message, char_u *a1, int hl)
+{
+    vim_snprintf((char *)IObuff, IOSIZE, (char *)message, a1);
+    give_warning(IObuff, hl);
+}
+
 /*
  * Advance msg cursor to column "col".
  */

src/proto/message.pro

@@ -75,6 +75,7 @@ void verbose_leave_scroll(void);
 void verbose_stop(void);
 int verbose_open(void);
 void give_warning(char_u *message, int hl);
+void give_warning2(char_u *message, char_u *a1, int hl);
 void msg_advance(int col);
 int do_dialog(int type, char_u *title, char_u *message, char_u *buttons, int dfltbutton, char_u *textfield, int ex_cmd);
 void display_confirm_msg(void);

src/testdir/test_vimscript.vim

@@ -1381,10 +1381,12 @@ func Test_endfunction_trailing()
 
     set verbose=1
     exe "func Xtest()\necho 'hello'\nendfunc \" garbage"
+    call assert_notmatch('W22:', split(execute('1messages'), "\n")[0])
     call assert_true(exists('*Xtest'))
     delfunc Xtest
 
-    call assert_fails("func Xtest()\necho 'hello'\nendfunc garbage", 'E946')
+    exe "func Xtest()\necho 'hello'\nendfunc garbage"
+    call assert_match('W22:', split(execute('1messages'), "\n")[0])
     call assert_true(exists('*Xtest'))
     delfunc Xtest
     set verbose=0

src/userfunc.c

@@ -2137,7 +2137,9 @@ ex_function(exarg_T *eap)
 		    /* Another command follows. */
 		    eap->nextcmd = line_arg;
 		else if (*p != NUL && *p != '"' && p_verbose > 0)
-		    EMSG2((char_u *)_("E946: Text found after :endfunction: %s"), p);
+		    give_warning2(
+			 (char_u *)_("W22: Text found after :endfunction: %s"),
+			 p, TRUE);
 		if (line_arg == NULL)
 		    vim_free(theline);
 		break;

src/version.c

@@ -764,6 +764,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    663,
 /**/
     662,
 /**/