AST-reflecting approach

Grammar/python.gram

@@ -1075,13 +1075,13 @@ starred_expression[expr_ty]:
 kwarg_or_starred[KeywordOrStarred*]:
     | invalid_kwarg
     | a=NAME '=' b=expression? {
-        _PyPegen_keyword_or_starred(p, CHECK(keyword_ty, _PyAST_keyword(a->v.Name.id, b ? b : a, EXTRA)), 1) }
+        _PyPegen_keyword_or_starred(p, CHECK(keyword_ty, _PyAST_keyword(a->v.Name.id, b, EXTRA)), 1) }
     | a=starred_expression { _PyPegen_keyword_or_starred(p, a, 0) }
 
 kwarg_or_double_starred[KeywordOrStarred*]:
     | invalid_kwarg
     | a=NAME '=' b=expression? {
-        _PyPegen_keyword_or_starred(p, CHECK(keyword_ty, _PyAST_keyword(a->v.Name.id, b ? b : a, EXTRA)), 1) }
+        _PyPegen_keyword_or_starred(p, CHECK(keyword_ty, _PyAST_keyword(a->v.Name.id, b, EXTRA)), 1) }
     | '**' a=expression { _PyPegen_keyword_or_starred(p, CHECK(keyword_ty, _PyAST_keyword(NULL, a, EXTRA)), 1) }
 
 # ASSIGNMENT TARGETS

Parser/Python.asdl

@@ -125,7 +125,7 @@ module Python
            attributes (int lineno, int col_offset, int? end_lineno, int? end_col_offset)
 
     -- keyword arguments supplied to call (NULL identifier for **kwargs)
-    keyword = (identifier? arg, expr value)
+    keyword = (identifier? arg, expr? value)
                attributes (int lineno, int col_offset, int? end_lineno, int? end_col_offset)
 
     -- import name with optional 'as' alias.

Python/ast.c

@@ -87,9 +87,11 @@ static int
 validate_keywords(struct validator *state, asdl_keyword_seq *keywords)
 {
     assert(!PyErr_Occurred());
-    for (Py_ssize_t i = 0; i < asdl_seq_LEN(keywords); i++)
-        if (!validate_expr(state, (asdl_seq_GET(keywords, i))->value, Load))
+    for (Py_ssize_t i = 0; i < asdl_seq_LEN(keywords); i++) {
+        keyword_ty k = asdl_seq_GET(keywords, i);
+        if (k->value && !validate_expr(state, k->value, Load))
             return 0;
+    }
     return 1;
 }
 

Python/ast_opt.c

@@ -1169,7 +1169,7 @@ astfold_expr(expr_ty node_, PyArena *ctx_, _PyASTOptimizeState *state)
 static int
 astfold_keyword(keyword_ty node_, PyArena *ctx_, _PyASTOptimizeState *state)
 {
-    CALL(astfold_expr, expr_ty, node_->value);
+    CALL_OPT(astfold_expr, expr_ty, node_->value);
     return 1;
 }
 

Python/compile.c

@@ -5237,7 +5237,12 @@ compiler_subkwargs(struct compiler *c, location loc,
     if (n > 1 && !big) {
         for (i = begin; i < end; i++) {
             kw = asdl_seq_GET(keywords, i);
-            VISIT(c, expr, kw->value);
+            if (kw->value) {
+                VISIT(c, expr, kw->value);
+            }
+            else {
+               RETURN_IF_ERROR(compiler_nameop(c, loc, kw->arg, Load));
+            }
         }
         keys = PyTuple_New(n);
         if (keys == NULL) {
@@ -5257,7 +5262,12 @@ compiler_subkwargs(struct compiler *c, location loc,
     for (i = begin; i < end; i++) {
         kw = asdl_seq_GET(keywords, i);
         ADDOP_LOAD_CONST(c, loc, kw->arg);
-        VISIT(c, expr, kw->value);
+        if (kw->value) {
+            VISIT(c, expr, kw->value);
+        }
+        else {
+            RETURN_IF_ERROR(compiler_nameop(c, loc, kw->arg, Load));
+        }
         if (big) {
             ADDOP_I(c, NO_LOCATION, MAP_ADD, 1);
         }
@@ -5370,6 +5380,7 @@ compiler_call_helper(struct compiler *c, location loc,
                     ADDOP_I(c, loc, BUILD_MAP, 0);
                     have_dict = 1;
                 }
+                assert(kw->value);
                 VISIT(c, expr, kw->value);
                 ADDOP_I(c, loc, DICT_MERGE, 1);
             }
@@ -6018,7 +6029,12 @@ compiler_dictcomp(struct compiler *c, expr_ty e)
 static int
 compiler_visit_keyword(struct compiler *c, keyword_ty k)
 {
-    VISIT(c, expr, k->value);
+    if (k->value) {
+        VISIT(c, expr, k->value);
+    }
+    else {
+        RETURN_IF_ERROR(compiler_nameop(c, LOC(k), k->arg, Load));
+    }
     return SUCCESS;
 }
 

Python/symtable.c

@@ -1947,6 +1947,26 @@ symtable_handle_namedexpr(struct symtable *st, expr_ty e)
     return 1;
 }
 
+static int
+symtable_name(struct symtable *st, identifier name, expr_context_ty ctx,
+              int lineno, int col_offset, int end_lineno, int end_col_offset)
+{
+    if (!symtable_add_def(st, name,
+                          ctx == Load ? USE : DEF_LOCAL,
+                          lineno, col_offset, end_lineno, end_col_offset))
+        return 0;
+    /* Special-case super: it counts as a use of __class__ */
+    if (ctx == Load &&
+        _PyST_IsFunctionLike(st->st_cur) &&
+        _PyUnicode_EqualToASCIIString(name, "super")) {
+        if (!symtable_add_def(st, &_Py_ID(__class__), USE,
+                              lineno, col_offset,
+                              end_lineno, end_col_offset))
+            return 0;
+    }
+    return 1;
+}
+
 static int
 symtable_visit_expr(struct symtable *st, expr_ty e)
 {
@@ -2089,16 +2109,8 @@ symtable_visit_expr(struct symtable *st, expr_ty e)
             VISIT(st, expr, e->v.Slice.step)
         break;
     case Name_kind:
-        if (!symtable_add_def(st, e->v.Name.id,
-                              e->v.Name.ctx == Load ? USE : DEF_LOCAL, LOCATION(e)))
+        if (!symtable_name(st, e->v.Name.id, e->v.Name.ctx, LOCATION(e)))
             VISIT_QUIT(st, 0);
-        /* Special-case super: it counts as a use of __class__ */
-        if (e->v.Name.ctx == Load &&
-            _PyST_IsFunctionLike(st->st_cur) &&
-            _PyUnicode_EqualToASCIIString(e->v.Name.id, "super")) {
-            if (!symtable_add_def(st, &_Py_ID(__class__), USE, LOCATION(e)))
-                VISIT_QUIT(st, 0);
-        }
         break;
     /* child nodes of List and Tuple will have expr_context set */
     case List_kind:
@@ -2423,8 +2435,12 @@ symtable_visit_comprehension(struct symtable *st, comprehension_ty lc)
 static int
 symtable_visit_keyword(struct symtable *st, keyword_ty k)
 {
-    VISIT(st, expr, k->value);
-    return 1;
+    if (k->value) {
+        VISIT(st, expr, k->value);
+        return 1;
+    }
+
+    return symtable_name(st, k->arg, Load, LOCATION(k));
 }