[3.12] gh-110938: Fix error messages for indented blocks with functio… (#110990)

[3.12] gh-110938: Fix error messages for indented blocks with functions and classes with generic type parameters (GH-110973)
(cherry picked from commit 24e4ec7766fd471deb5b7e5087f0e7dba8576cfb)

Co-authored-by: Pablo Galindo Salgado <Pablogsal@gmail.com>

4 files changed, 46 insertions, 22 deletions

diff --git a/Grammar/python.gram b/Grammar/python.gram
index c442db2..a4fd3f2 100644
--- a/Grammar/python.gram
+++ b/Grammar/python.gram
@@ -1369,11 +1369,11 @@ invalid_for_stmt:
     | [ASYNC] a='for' star_targets 'in' star_expressions ':' NEWLINE !INDENT {
         RAISE_INDENTATION_ERROR("expected an indented block after 'for' statement on line %d", a->lineno) }
 invalid_def_raw:
-    | [ASYNC] a='def' NAME '(' [params] ')' ['->' expression] ':' NEWLINE !INDENT {
+    | [ASYNC] a='def' NAME [type_params] '(' [params] ')' ['->' expression] ':' NEWLINE !INDENT {
         RAISE_INDENTATION_ERROR("expected an indented block after function definition on line %d", a->lineno) }
 invalid_class_def_raw:
-    | 'class' NAME ['(' [arguments] ')'] NEWLINE { RAISE_SYNTAX_ERROR("expected ':'") }
-    | a='class' NAME ['(' [arguments] ')'] ':' NEWLINE !INDENT {
+    | 'class' NAME [type_params] ['(' [arguments] ')'] NEWLINE { RAISE_SYNTAX_ERROR("expected ':'") }
+    | a='class' NAME [type_params] ['(' [arguments] ')'] ':' NEWLINE !INDENT {
         RAISE_INDENTATION_ERROR("expected an indented block after class definition on line %d", a->lineno) }
 
 invalid_double_starred_kvpairs:
diff --git a/Lib/test/test_syntax.py b/Lib/test/test_syntax.py
index 52fc357..f5cf966 100644
--- a/Lib/test/test_syntax.py
+++ b/Lib/test/test_syntax.py
@@ -1446,11 +1446,21 @@ Specialized indentation errors:
    Traceback (most recent call last):
    IndentationError: expected an indented block after function definition on line 1
 
+   >>> def foo[T](x, /, y, *, z=2):
+   ... pass
+   Traceback (most recent call last):
+   IndentationError: expected an indented block after function definition on line 1
+
    >>> class Blech(A):
    ... pass
    Traceback (most recent call last):
    IndentationError: expected an indented block after class definition on line 1
 
+   >>> class Blech[T](A):
+   ... pass
+   Traceback (most recent call last):
+   IndentationError: expected an indented block after class definition on line 1
+
    >>> match something:
    ... pass
    Traceback (most recent call last):
diff --git a/Misc/NEWS.d/next/Core and Builtins/2023-10-17-11-03-45.gh-issue-110938.X3sbMb.rst b/Misc/NEWS.d/next/Core and Builtins/2023-10-17-11-03-45.gh-issue-110938.X3sbMb.rst
new file mode 100644
index 0000000..a2f9319
--- /dev/null
+++ b/Misc/NEWS.d/next/Core and Builtins/2023-10-17-11-03-45.gh-issue-110938.X3sbMb.rst
@@ -0,0 +1,2 @@
+Fix error messages for indented blocks with functions and classes with
+generic type parameters. Patch by Pablo Galindo
diff --git a/Parser/parser.c b/Parser/parser.c
index 42201c4..25b4ead 100644
--- a/Parser/parser.c
+++ b/Parser/parser.c
@@ -24069,7 +24069,7 @@ invalid_for_stmt_rule(Parser *p)
 }
 
 // invalid_def_raw:
-//     | ASYNC? 'def' NAME '(' params? ')' ['->' expression] ':' NEWLINE !INDENT
+//     | ASYNC? 'def' NAME type_params? '(' params? ')' ['->' expression] ':' NEWLINE !INDENT
 static void *
 invalid_def_raw_rule(Parser *p)
 {
@@ -24082,12 +24082,12 @@ invalid_def_raw_rule(Parser *p)
     }
     void * _res = NULL;
     int _mark = p->mark;
-    { // ASYNC? 'def' NAME '(' params? ')' ['->' expression] ':' NEWLINE !INDENT
+    { // ASYNC? 'def' NAME type_params? '(' params? ')' ['->' expression] ':' NEWLINE !INDENT
         if (p->error_indicator) {
             p->level--;
             return NULL;
         }
-        D(fprintf(stderr, "%*c> invalid_def_raw[%d-%d]: %s\n", p->level, ' ', _mark, p->mark, "ASYNC? 'def' NAME '(' params? ')' ['->' expression] ':' NEWLINE !INDENT"));
+        D(fprintf(stderr, "%*c> invalid_def_raw[%d-%d]: %s\n", p->level, ' ', _mark, p->mark, "ASYNC? 'def' NAME type_params? '(' params? ')' ['->' expression] ':' NEWLINE !INDENT"));
         Token * _literal;
         Token * _literal_1;
         Token * _literal_2;
@@ -24097,6 +24097,8 @@ invalid_def_raw_rule(Parser *p)
         UNUSED(_opt_var_1); // Silence compiler warnings
         void *_opt_var_2;
         UNUSED(_opt_var_2); // Silence compiler warnings
+        void *_opt_var_3;
+        UNUSED(_opt_var_3); // Silence compiler warnings
         Token * a;
         expr_ty name_var;
         Token * newline_var;
@@ -24107,13 +24109,15 @@ invalid_def_raw_rule(Parser *p)
             &&
             (name_var = _PyPegen_name_token(p))  // NAME
             &&
+            (_opt_var_1 = type_params_rule(p), !p->error_indicator)  // type_params?
+            &&
             (_literal = _PyPegen_expect_token(p, 7))  // token='('
             &&
-            (_opt_var_1 = params_rule(p), !p->error_indicator)  // params?
+            (_opt_var_2 = params_rule(p), !p->error_indicator)  // params?
             &&
             (_literal_1 = _PyPegen_expect_token(p, 8))  // token=')'
             &&
-            (_opt_var_2 = _tmp_226_rule(p), !p->error_indicator)  // ['->' expression]
+            (_opt_var_3 = _tmp_226_rule(p), !p->error_indicator)  // ['->' expression]
             &&
             (_literal_2 = _PyPegen_expect_token(p, 11))  // token=':'
             &&
@@ -24122,7 +24126,7 @@ invalid_def_raw_rule(Parser *p)
             _PyPegen_lookahead_with_int(0, _PyPegen_expect_token, p, INDENT)  // token=INDENT
         )
         {
-            D(fprintf(stderr, "%*c+ invalid_def_raw[%d-%d]: %s succeeded!\n", p->level, ' ', _mark, p->mark, "ASYNC? 'def' NAME '(' params? ')' ['->' expression] ':' NEWLINE !INDENT"));
+            D(fprintf(stderr, "%*c+ invalid_def_raw[%d-%d]: %s succeeded!\n", p->level, ' ', _mark, p->mark, "ASYNC? 'def' NAME type_params? '(' params? ')' ['->' expression] ':' NEWLINE !INDENT"));
             _res = RAISE_INDENTATION_ERROR ( "expected an indented block after function definition on line %d" , a -> lineno );
             if (_res == NULL && PyErr_Occurred()) {
                 p->error_indicator = 1;
@@ -24133,7 +24137,7 @@ invalid_def_raw_rule(Parser *p)
         }
         p->mark = _mark;
         D(fprintf(stderr, "%*c%s invalid_def_raw[%d-%d]: %s failed!\n", p->level, ' ',
-                  p->error_indicator ? "ERROR!" : "-", _mark, p->mark, "ASYNC? 'def' NAME '(' params? ')' ['->' expression] ':' NEWLINE !INDENT"));
+                  p->error_indicator ? "ERROR!" : "-", _mark, p->mark, "ASYNC? 'def' NAME type_params? '(' params? ')' ['->' expression] ':' NEWLINE !INDENT"));
     }
     _res = NULL;
   done:
@@ -24142,8 +24146,8 @@ invalid_def_raw_rule(Parser *p)
 }
 
 // invalid_class_def_raw:
-//     | 'class' NAME ['(' arguments? ')'] NEWLINE
-//     | 'class' NAME ['(' arguments? ')'] ':' NEWLINE !INDENT
+//     | 'class' NAME type_params? ['(' arguments? ')'] NEWLINE
+//     | 'class' NAME type_params? ['(' arguments? ')'] ':' NEWLINE !INDENT
 static void *
 invalid_class_def_raw_rule(Parser *p)
 {
@@ -24156,15 +24160,17 @@ invalid_class_def_raw_rule(Parser *p)
     }
     void * _res = NULL;
     int _mark = p->mark;
-    { // 'class' NAME ['(' arguments? ')'] NEWLINE
+    { // 'class' NAME type_params? ['(' arguments? ')'] NEWLINE
         if (p->error_indicator) {
             p->level--;
             return NULL;
         }
-        D(fprintf(stderr, "%*c> invalid_class_def_raw[%d-%d]: %s\n", p->level, ' ', _mark, p->mark, "'class' NAME ['(' arguments? ')'] NEWLINE"));
+        D(fprintf(stderr, "%*c> invalid_class_def_raw[%d-%d]: %s\n", p->level, ' ', _mark, p->mark, "'class' NAME type_params? ['(' arguments? ')'] NEWLINE"));
         Token * _keyword;
         void *_opt_var;
         UNUSED(_opt_var); // Silence compiler warnings
+        void *_opt_var_1;
+        UNUSED(_opt_var_1); // Silence compiler warnings
         expr_ty name_var;
         Token * newline_var;
         if (
@@ -24172,12 +24178,14 @@ invalid_class_def_raw_rule(Parser *p)
             &&
             (name_var = _PyPegen_name_token(p))  // NAME
             &&
-            (_opt_var = _tmp_227_rule(p), !p->error_indicator)  // ['(' arguments? ')']
+            (_opt_var = type_params_rule(p), !p->error_indicator)  // type_params?
+            &&
+            (_opt_var_1 = _tmp_227_rule(p), !p->error_indicator)  // ['(' arguments? ')']
             &&
             (newline_var = _PyPegen_expect_token(p, NEWLINE))  // token='NEWLINE'
         )
         {
-            D(fprintf(stderr, "%*c+ invalid_class_def_raw[%d-%d]: %s succeeded!\n", p->level, ' ', _mark, p->mark, "'class' NAME ['(' arguments? ')'] NEWLINE"));
+            D(fprintf(stderr, "%*c+ invalid_class_def_raw[%d-%d]: %s succeeded!\n", p->level, ' ', _mark, p->mark, "'class' NAME type_params? ['(' arguments? ')'] NEWLINE"));
             _res = RAISE_SYNTAX_ERROR ( "expected ':'" );
             if (_res == NULL && PyErr_Occurred()) {
                 p->error_indicator = 1;
@@ -24188,17 +24196,19 @@ invalid_class_def_raw_rule(Parser *p)
         }
         p->mark = _mark;
         D(fprintf(stderr, "%*c%s invalid_class_def_raw[%d-%d]: %s failed!\n", p->level, ' ',
-                  p->error_indicator ? "ERROR!" : "-", _mark, p->mark, "'class' NAME ['(' arguments? ')'] NEWLINE"));
+                  p->error_indicator ? "ERROR!" : "-", _mark, p->mark, "'class' NAME type_params? ['(' arguments? ')'] NEWLINE"));
     }
-    { // 'class' NAME ['(' arguments? ')'] ':' NEWLINE !INDENT
+    { // 'class' NAME type_params? ['(' arguments? ')'] ':' NEWLINE !INDENT
         if (p->error_indicator) {
             p->level--;
             return NULL;
         }
-        D(fprintf(stderr, "%*c> invalid_class_def_raw[%d-%d]: %s\n", p->level, ' ', _mark, p->mark, "'class' NAME ['(' arguments? ')'] ':' NEWLINE !INDENT"));
+        D(fprintf(stderr, "%*c> invalid_class_def_raw[%d-%d]: %s\n", p->level, ' ', _mark, p->mark, "'class' NAME type_params? ['(' arguments? ')'] ':' NEWLINE !INDENT"));
         Token * _literal;
         void *_opt_var;
         UNUSED(_opt_var); // Silence compiler warnings
+        void *_opt_var_1;
+        UNUSED(_opt_var_1); // Silence compiler warnings
         Token * a;
         expr_ty name_var;
         Token * newline_var;
@@ -24207,7 +24217,9 @@ invalid_class_def_raw_rule(Parser *p)
             &&
             (name_var = _PyPegen_name_token(p))  // NAME
             &&
-            (_opt_var = _tmp_228_rule(p), !p->error_indicator)  // ['(' arguments? ')']
+            (_opt_var = type_params_rule(p), !p->error_indicator)  // type_params?
+            &&
+            (_opt_var_1 = _tmp_228_rule(p), !p->error_indicator)  // ['(' arguments? ')']
             &&
             (_literal = _PyPegen_expect_token(p, 11))  // token=':'
             &&
@@ -24216,7 +24228,7 @@ invalid_class_def_raw_rule(Parser *p)
             _PyPegen_lookahead_with_int(0, _PyPegen_expect_token, p, INDENT)  // token=INDENT
         )
         {
-            D(fprintf(stderr, "%*c+ invalid_class_def_raw[%d-%d]: %s succeeded!\n", p->level, ' ', _mark, p->mark, "'class' NAME ['(' arguments? ')'] ':' NEWLINE !INDENT"));
+            D(fprintf(stderr, "%*c+ invalid_class_def_raw[%d-%d]: %s succeeded!\n", p->level, ' ', _mark, p->mark, "'class' NAME type_params? ['(' arguments? ')'] ':' NEWLINE !INDENT"));
             _res = RAISE_INDENTATION_ERROR ( "expected an indented block after class definition on line %d" , a -> lineno );
             if (_res == NULL && PyErr_Occurred()) {
                 p->error_indicator = 1;
@@ -24227,7 +24239,7 @@ invalid_class_def_raw_rule(Parser *p)
         }
         p->mark = _mark;
         D(fprintf(stderr, "%*c%s invalid_class_def_raw[%d-%d]: %s failed!\n", p->level, ' ',
-                  p->error_indicator ? "ERROR!" : "-", _mark, p->mark, "'class' NAME ['(' arguments? ')'] ':' NEWLINE !INDENT"));
+                  p->error_indicator ? "ERROR!" : "-", _mark, p->mark, "'class' NAME type_params? ['(' arguments? ')'] ':' NEWLINE !INDENT"));
     }
     _res = NULL;
   done: