[3.10] bpo-45727: Only trigger the 'did you forgot a comma' error suggestion if inside parentheses. (GH-29767)

Backport of GH-29757

Co-authored-by: Pablo Galindo <pablogsal@gmail.com>
diff --git a/Parser/parser.c b/Parser/parser.c
index b14092a..0b6450c 100644
--- a/Parser/parser.c
+++ b/Parser/parser.c
@@ -18288,7 +18288,7 @@ invalid_expression_rule(Parser *p)
         )
         {
             D(fprintf(stderr, "%*c+ invalid_expression[%d-%d]: %s succeeded!\n", p->level, ' ', _mark, p->mark, "!(NAME STRING | SOFT_KEYWORD) disjunction expression_without_invalid"));
-            _res = _PyPegen_check_legacy_stmt ( p , a ) ? NULL : RAISE_SYNTAX_ERROR_KNOWN_RANGE ( a , b , "invalid syntax. Perhaps you forgot a comma?" );
+            _res = _PyPegen_check_legacy_stmt ( p , a ) ? NULL : p -> tokens [ p -> mark - 1 ] -> level == 0 ? NULL : RAISE_SYNTAX_ERROR_KNOWN_RANGE ( a , b , "invalid syntax. Perhaps you forgot a comma?" );
             if (_res == NULL && PyErr_Occurred()) {
                 p->error_indicator = 1;
                 D(p->level--);
diff --git a/Parser/pegen.c b/Parser/pegen.c
index 8946aa3..e37aaf7 100644
--- a/Parser/pegen.c
+++ b/Parser/pegen.c
@@ -692,6 +692,8 @@ initialize_token(Parser *p, Token *token, const char *start, const char *end, in
         return -1;
     }
 
+    token->level = p->tok->level;
+
     const char *line_start = token_type == STRING ? p->tok->multi_line_start : p->tok->line_start;
     int lineno = token_type == STRING ? p->tok->first_lineno : p->tok->lineno;
     int end_lineno = p->tok->lineno;
@@ -1357,7 +1359,7 @@ _PyPegen_run_parser(Parser *p)
         if (p->fill == 0) {
             RAISE_SYNTAX_ERROR("error at start before reading any input");
         }
-        else if (p->tok->done == E_EOF) {
+        else if (last_token->type == ERRORTOKEN && p->tok->done == E_EOF) {
             if (p->tok->level) {
                 raise_unclosed_parentheses_error(p);
             } else {
diff --git a/Parser/pegen.h b/Parser/pegen.h
index 40222d6..04c7b9d 100644
--- a/Parser/pegen.h
+++ b/Parser/pegen.h
@@ -33,6 +33,7 @@ typedef struct _memo {
 typedef struct {
     int type;
     PyObject *bytes;
+    int level;
     int lineno, col_offset, end_lineno, end_col_offset;
     Memo *memo;
 } Token;
diff --git a/Parser/pegen_errors.c b/Parser/pegen_errors.c
index 694184a..93057d1 100644
--- a/Parser/pegen_errors.c
+++ b/Parser/pegen_errors.c
@@ -399,7 +399,7 @@ _Pypegen_set_syntax_error(Parser* p, Token* last_token) {
         RAISE_SYNTAX_ERROR("error at start before reading any input");
     }
     // Parser encountered EOF (End of File) unexpectedtly
-    if (p->tok->done == E_EOF) {
+    if (last_token->type == ERRORTOKEN && p->tok->done == E_EOF) {
         if (p->tok->level) {
             raise_unclosed_parentheses_error(p);
         } else {
@@ -422,4 +422,4 @@ _Pypegen_set_syntax_error(Parser* p, Token* last_token) {
     // _PyPegen_tokenize_full_source_to_check_for_errors will override the existing
     // generic SyntaxError we just raised if errors are found.
     _PyPegen_tokenize_full_source_to_check_for_errors(p);
-}
\ No newline at end of file
+}