Revert "Berry `var` allowed in with walrus operator `:=` (#19018)" (#19019)

This reverts commit 8f06552eee.

CHANGELOG.md

@@ -9,7 +9,6 @@ All notable changes to this project will be documented in this file.
 - Matter add option to disable bridge mode (#18992)
 - Support for SGP41 TVOC/NOx Sensor (#18880)
 - Command ``BrRestart`` to restart the Berry VM (experimental)
-- Berry `var` allowed in with walrus operator `:=`
 
 ### Breaking Changed
 - Berry `bool( [] )` and `bool( {} )` now evaluate as `false` (#18986)

lib/libesp32/berry/src/be_parser.c

@@ -1135,22 +1135,8 @@ static void sub_expr(bparser *parser, bexpdesc *e, int prio)
 static void walrus_expr(bparser *parser, bexpdesc *e)
 {
     int line = parser->lexer.linenumber;
-    btokentype op = next_type(parser);
-    if (op == KeyVar) {
-        /* 'var' ID ':=' expr */
-        scan_next_token(parser); /* skip 'var' */
-        bstring *name;
-        name = next_token(parser).u.s;
-        match_token(parser, TokenId); /* match and skip ID */
-        new_var(parser, name, e); /* new variable */         
-        op = next_type(parser);
-        if (op != OptWalrus) {
-            parser_error(parser, "'var' in expr must be followed by ':='");
-        }
-    } else {
     sub_expr(parser, e, ASSIGN_OP_PRIO);    /* left expression */
-        op = next_type(parser);
-    }
+    btokentype op = next_type(parser);
     if (op == OptWalrus) {
         check_symbol(parser, e);
         bexpdesc e1 = *e;           /* copy var to e1, e will get the result of expression */
@@ -1163,7 +1149,8 @@ static void walrus_expr(bparser *parser, bexpdesc *e)
         }
         if (be_code_setvar(parser->finfo, &e1, e, btrue /* do not release register */ )) {
             parser->lexer.linenumber = line;
-            parser_error(parser, "try to assign constant expressions.");
+            parser_error(parser,
+                "try to assign constant expressions.");
         }
     }
 }