patch 9.1.0314: Vim9: Can define a class in a function

Problem:  Vim9: Can define a class in a function
          (Doug Kearns)
Solution: Give an error for a class defined in a function,
          slightly reword some public error messages
          (Yegappan Lakshmanan)

fixes: #13184
fixes: #13326
closes: #14537

Signed-off-by: Yegappan Lakshmanan <yegappan@yahoo.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/errors.h b/src/errors.h
index 00f7df0..4387a29 100644
--- a/src/errors.h
+++ b/src/errors.h
@@ -3412,9 +3412,9 @@
 EXTERN char e_invalid_type_for_object_variable_str[]
 	INIT(= N_("E1330: Invalid type for object variable: %s"));
 EXTERN char e_public_must_be_followed_by_var_static_final_or_const[]
-	INIT(= N_("E1331: Public must be followed by \"var\" or \"static\" or \"final\" or \"const\""));
+	INIT(= N_("E1331: public must be followed by \"var\" or \"static\" or \"final\" or \"const\""));
 EXTERN char e_public_variable_name_cannot_start_with_underscore_str[]
-	INIT(= N_("E1332: Public variable name cannot start with underscore: %s"));
+	INIT(= N_("E1332: public variable name cannot start with underscore: %s"));
 EXTERN char e_cannot_access_protected_variable_str[]
 	INIT(= N_("E1333: Cannot access protected variable \"%s\" in class \"%s\""));
 // E1334 unused
@@ -3532,9 +3532,9 @@
 EXTERN char e_object_method_str_accessible_only_using_object_str[]
 	INIT(= N_("E1386: Object method \"%s\" accessible only using class \"%s\" object"));
 EXTERN char e_public_variable_not_supported_in_interface[]
-	INIT(= N_("E1387: Public variable not supported in an interface"));
+	INIT(= N_("E1387: public variable not supported in an interface"));
 EXTERN char e_public_keyword_not_supported_for_method[]
-	INIT(= N_("E1388: Public keyword not supported for a method"));
+	INIT(= N_("E1388: public keyword not supported for a method"));
 EXTERN char e_missing_name_after_implements[]
 	INIT(= N_("E1389: Missing name after implements"));
 EXTERN char e_cannot_use_an_object_variable_except_with_the_new_method_str[]
@@ -3615,6 +3615,8 @@
 	INIT(= N_("E1427: Enum \"%s\" name cannot be modified"));
 EXTERN char e_duplicate_enum_str[]
 	INIT(= N_("E1428: Duplicate enum value: %s"));
+EXTERN char e_class_can_only_be_used_in_script[]
+	INIT(= N_("E1429: Class can only be used in a script"));
 #endif
 // E1429 - E1499 unused (reserved for Vim9 class support)
 EXTERN char e_cannot_mix_positional_and_non_positional_str[]
diff --git a/src/testdir/test_vim9_class.vim b/src/testdir/test_vim9_class.vim
index 6d6d178..5957f57 100644
--- a/src/testdir/test_vim9_class.vim
+++ b/src/testdir/test_vim9_class.vim
@@ -400,7 +400,7 @@
       enddef
     endclass
   END
-  v9.CheckSourceFailure(lines, 'E1331: Public must be followed by "var" or "static"', 3)
+  v9.CheckSourceFailure(lines, 'E1388: public keyword not supported for a method', 3)
 
   # Using the "public" keyword when defining a class method
   lines =<< trim END
@@ -410,7 +410,7 @@
       enddef
     endclass
   END
-  v9.CheckSourceFailure(lines, 'E1388: Public keyword not supported for a method', 3)
+  v9.CheckSourceFailure(lines, 'E1388: public keyword not supported for a method', 3)
 
   # Using the "public" keyword when defining an object protected method
   lines =<< trim END
@@ -420,7 +420,7 @@
       enddef
     endclass
   END
-  v9.CheckSourceFailure(lines, 'E1331: Public must be followed by "var" or "static"', 3)
+  v9.CheckSourceFailure(lines, 'E1388: public keyword not supported for a method', 3)
 
   # Using the "public" keyword when defining a class protected method
   lines =<< trim END
@@ -430,7 +430,7 @@
       enddef
     endclass
   END
-  v9.CheckSourceFailure(lines, 'E1388: Public keyword not supported for a method', 3)
+  v9.CheckSourceFailure(lines, 'E1388: public keyword not supported for a method', 3)
 
   # Using a "def" keyword without an object method name
   lines =<< trim END
@@ -1191,7 +1191,7 @@
       public var _val = 10
     endclass
   END
-  v9.CheckSourceFailure(lines, 'E1332: Public variable name cannot start with underscore: public var _val = 10', 3)
+  v9.CheckSourceFailure(lines, 'E1332: public variable name cannot start with underscore: public var _val = 10', 3)
 
   lines =<< trim END
     vim9script
@@ -1287,7 +1287,7 @@
       public val = 1
     endclass
   END
-  v9.CheckSourceFailure(lines, 'E1331: Public must be followed by "var" or "static"', 3)
+  v9.CheckSourceFailure(lines, 'E1331: public must be followed by "var" or "static"', 3)
 
   # Modify a instance variable using the class name in the script context
   lines =<< trim END
@@ -6537,7 +6537,7 @@
       public static var num: number
     endinterface
   END
-  v9.CheckSourceFailure(lines, 'E1387: Public variable not supported in an interface', 3)
+  v9.CheckSourceFailure(lines, 'E1387: public variable not supported in an interface', 3)
 
   lines =<< trim END
     vim9script
@@ -6545,7 +6545,7 @@
       public static var num: number
     endinterface
   END
-  v9.CheckSourceFailure(lines, 'E1387: Public variable not supported in an interface', 3)
+  v9.CheckSourceFailure(lines, 'E1387: public variable not supported in an interface', 3)
 
   lines =<< trim END
     vim9script
@@ -10625,4 +10625,17 @@
   v9.CheckScriptFailure(lines, 'E476: Invalid command: pass', 1)
 enddef
 
+" Test for defining a class in a function
+def Test_class_definition_in_a_function()
+  var lines =<< trim END
+    vim9script
+    def Foo()
+      class A
+      endclass
+    enddef
+    defcompile
+  END
+  v9.CheckScriptFailure(lines, 'E1429: Class can only be used in a script', 1)
+enddef
+
 " vim: ts=8 sw=2 sts=2 expandtab tw=80 fdm=marker
diff --git a/src/version.c b/src/version.c
index dd7f203..9faa053 100644
--- a/src/version.c
+++ b/src/version.c
@@ -705,6 +705,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    314,
+/**/
     313,
 /**/
     312,
diff --git a/src/vim9class.c b/src/vim9class.c
index a6b3ee2..52c2f76 100644
--- a/src/vim9class.c
+++ b/src/vim9class.c
@@ -2080,6 +2080,12 @@
 	    has_public = TRUE;
 	    p = skipwhite(line + 6);
 
+	    if (STRNCMP(p, "def", 3) == 0)
+	    {
+		emsg(_(e_public_keyword_not_supported_for_method));
+		break;
+	    }
+
 	    if (STRNCMP(p, "var", 3) != 0 && STRNCMP(p, "static", 6) != 0
 		&& STRNCMP(p, "final", 5) != 0 && STRNCMP(p, "const", 5) != 0)
 	    {
diff --git a/src/vim9compile.c b/src/vim9compile.c
index c6b0247..7e1d911 100644
--- a/src/vim9compile.c
+++ b/src/vim9compile.c
@@ -4028,10 +4028,13 @@
 		    line = (char_u *)"";
 		    break;
 
+	    case CMD_class:
+		    emsg(_(e_class_can_only_be_used_in_script));
+		    goto erret;
+
 	    case CMD_type:
 		    emsg(_(e_type_can_only_be_used_in_script));
 		    goto erret;
-		    break;
 
 	    case CMD_global:
 		    if (check_global_and_subst(ea.cmd, p) == FAIL)