better col_offsets for "for" statements with tuple unpacking #6704

Patch from Frank Wierzbicki.

1 files changed, 12 insertions, 11 deletions

diff --git a/Python/ast.c b/Python/ast.c
index 0644da8..2f975ac 100644
--- a/Python/ast.c
+++ b/Python/ast.c
@@ -1047,7 +1047,7 @@ ast_for_listcomp(struct compiling *c, const node *n)
        list_if: 'if' test [list_iter]
        testlist_safe: test [(',' test)+ [',']]
     */
-    expr_ty elt;
+    expr_ty elt, first;
     asdl_seq *listcomps;
     int i, n_fors;
     node *ch;
@@ -1087,11 +1087,11 @@ ast_for_listcomp(struct compiling *c, const node *n)
         /* Check the # of children rather than the length of t, since
            [x for x, in ... ] has 1 element in t, but still requires a Tuple.
         */
+        first = (expr_ty)asdl_seq_GET(t, 0);
         if (NCH(for_ch) == 1)
-            lc = comprehension((expr_ty)asdl_seq_GET(t, 0), expression, NULL,
-                               c->c_arena);
+            lc = comprehension(first, expression, NULL, c->c_arena);
         else
-            lc = comprehension(Tuple(t, Store, LINENO(ch), ch->n_col_offset,
+            lc = comprehension(Tuple(t, Store, first->lineno, first->col_offset,
                                      c->c_arena),
                                expression, NULL, c->c_arena);
         if (!lc)
@@ -1226,7 +1226,7 @@ ast_for_genexp(struct compiling *c, const node *n)
     for (i = 0; i < n_fors; i++) {
         comprehension_ty ge;
         asdl_seq *t;
-        expr_ty expression;
+        expr_ty expression, first;
         node *for_ch;
         
         REQ(ch, gen_for);
@@ -1241,11 +1241,11 @@ ast_for_genexp(struct compiling *c, const node *n)
 
         /* Check the # of children rather than the length of t, since
            (x for x, in ...) has 1 element in t, but still requires a Tuple. */
+        first = (expr_ty)asdl_seq_GET(t, 0);
         if (NCH(for_ch) == 1)
-            ge = comprehension((expr_ty)asdl_seq_GET(t, 0), expression,
-                               NULL, c->c_arena);
+            ge = comprehension(first, expression, NULL, c->c_arena);
         else
-            ge = comprehension(Tuple(t, Store, LINENO(ch), ch->n_col_offset,
+            ge = comprehension(Tuple(t, Store, first->lineno, first->col_offset,
                                      c->c_arena),
                                expression, NULL, c->c_arena);
 
@@ -2844,7 +2844,7 @@ ast_for_for_stmt(struct compiling *c, const node *n)
 {
     asdl_seq *_target, *seq = NULL, *suite_seq;
     expr_ty expression;
-    expr_ty target;
+    expr_ty target, first;
     const node *node_target;
     /* for_stmt: 'for' exprlist 'in' testlist ':' suite ['else' ':' suite] */
     REQ(n, for_stmt);
@@ -2861,10 +2861,11 @@ ast_for_for_stmt(struct compiling *c, const node *n)
         return NULL;
     /* Check the # of children rather than the length of _target, since
        for x, in ... has 1 element in _target, but still requires a Tuple. */
+    first = (expr_ty)asdl_seq_GET(_target, 0);
     if (NCH(node_target) == 1)
-        target = (expr_ty)asdl_seq_GET(_target, 0);
+        target = first;
     else
-        target = Tuple(_target, Store, LINENO(n), n->n_col_offset, c->c_arena);
+        target = Tuple(_target, Store, first->lineno, first->col_offset, c->c_arena);
 
     expression = ast_for_testlist(c, CHILD(n, 3));
     if (!expression)