commit ec4717b67c17d8970828f4f9c81ac8794f65a44f
Author: Jason Merrill <jason@redhat.com>
Date: Sat Jun 18 15:03:12 2011 -0400
PR c++/43831
* parser.c (cp_parser_lambda_introducer): Complain about redundant
captures.
* semantics.c (add_capture): Likewise.
(register_capture_members): Clear IDENTIFIER_MARKED.
@@ -7485,6 +7485,10 @@ cp_parser_lambda_introducer (cp_parser* parser, tree lambda_expr)
/* Possibly capture `this'. */
if (cp_lexer_next_token_is_keyword (parser->lexer, RID_THIS))
{
+ location_t loc = cp_lexer_peek_token (parser->lexer)->location;
+ if (LAMBDA_EXPR_DEFAULT_CAPTURE_MODE (lambda_expr) == CPLD_COPY)
+ pedwarn (loc, 0, "explicit by-copy capture of %<this%> redundant "
+ "with by-copy capture default");
cp_lexer_consume_token (parser->lexer);
add_capture (lambda_expr,
/*id=*/this_identifier,
@@ -7568,6 +7572,21 @@ cp_parser_lambda_introducer (cp_parser* parser, tree lambda_expr)
capture_init_expr
= unqualified_name_lookup_error (capture_init_expr);
+ if (LAMBDA_EXPR_DEFAULT_CAPTURE_MODE (lambda_expr) != CPLD_NONE
+ && !explicit_init_p)
+ {
+ if (LAMBDA_EXPR_DEFAULT_CAPTURE_MODE (lambda_expr) == CPLD_COPY
+ && capture_kind == BY_COPY)
+ pedwarn (capture_token->location, 0, "explicit by-copy capture "
+ "of %qD redundant with by-copy capture default",
+ capture_id);
+ if (LAMBDA_EXPR_DEFAULT_CAPTURE_MODE (lambda_expr) == CPLD_REFERENCE
+ && capture_kind == BY_REFERENCE)
+ pedwarn (capture_token->location, 0, "explicit by-reference "
+ "capture of %qD redundant with by-reference capture "
+ "default", capture_id);
+ }
+
add_capture (lambda_expr,
capture_id,
capture_init_expr,
@@ -8516,8 +8516,8 @@ tree
add_capture (tree lambda, tree id, tree initializer, bool by_reference_p,
bool explicit_init_p)
{
- tree type;
- tree member;
+ char *buf;
+ tree type, member, name;
type = lambda_capture_field_type (initializer);
if (by_reference_p)
@@ -8527,18 +8527,31 @@ add_capture (tree lambda, tree id, tree initializer, bool by_reference_p,
error ("cannot capture %qE by reference", initializer);
}
+ /* Add __ to the beginning of the field name so that user code
+ won't find the field with name lookup. We can't just leave the name
+ unset because template instantiation uses the name to find
+ instantiated fields. */
+ buf = (char *) alloca (IDENTIFIER_LENGTH (id) + 3);
+ buf[1] = buf[0] = '_';
+ memcpy (buf + 2, IDENTIFIER_POINTER (id),
+ IDENTIFIER_LENGTH (id) + 1);
+ name = get_identifier (buf);
+
+ /* If TREE_TYPE isn't set, we're still in the introducer, so check
+ for duplicates. */
+ if (!TREE_TYPE (lambda))
+ {
+ if (IDENTIFIER_MARKED (name))
+ {
+ pedwarn (input_location, 0,
+ "already captured %qD in lambda expression", id);
+ return NULL_TREE;
+ }
+ IDENTIFIER_MARKED (name) = true;
+ }
+
/* Make member variable. */
- {
- /* Add __ to the beginning of the field name so that user code
- won't find the field with name lookup. We can't just leave the name
- unset because template instantiation uses the name to find
- instantiated fields. */
- char *buf = (char *) alloca (IDENTIFIER_LENGTH (id) + 3);
- buf[1] = buf[0] = '_';
- memcpy (buf + 2, IDENTIFIER_POINTER (id),
- IDENTIFIER_LENGTH (id) + 1);
- member = build_lang_decl (FIELD_DECL, get_identifier (buf), type);
- }
+ member = build_lang_decl (FIELD_DECL, name, type);
if (!explicit_init_p)
/* Normal captures are invisible to name lookup but uses are replaced
@@ -8548,6 +8561,9 @@ add_capture (tree lambda, tree id, tree initializer, bool by_reference_p,
always visible. */
DECL_NORMAL_CAPTURE_P (member) = true;
+ if (id == this_identifier)
+ LAMBDA_EXPR_THIS_CAPTURE (lambda) = member;
+
/* Add it to the appropriate closure class if we've started it. */
if (current_class_type && current_class_type == TREE_TYPE (lambda))
finish_member_declaration (member);
@@ -8555,13 +8571,6 @@ add_capture (tree lambda, tree id, tree initializer, bool by_reference_p,
LAMBDA_EXPR_CAPTURE_LIST (lambda)
= tree_cons (member, initializer, LAMBDA_EXPR_CAPTURE_LIST (lambda));
- if (id == this_identifier)
- {
- if (LAMBDA_EXPR_CAPTURES_THIS_P (lambda))
- error ("already captured %<this%> in lambda expression");
- LAMBDA_EXPR_THIS_CAPTURE (lambda) = member;
- }
-
if (TREE_TYPE (lambda))
return build_capture_proxy (member);
/* For explicit captures we haven't started the function yet, so we wait
@@ -8572,13 +8581,16 @@ add_capture (tree lambda, tree id, tree initializer, bool by_reference_p,
/* Register all the capture members on the list CAPTURES, which is the
LAMBDA_EXPR_CAPTURE_LIST for the lambda after the introducer. */
-void register_capture_members (tree captures)
+void
+register_capture_members (tree captures)
{
- if (captures)
- {
- register_capture_members (TREE_CHAIN (captures));
- finish_member_declaration (TREE_PURPOSE (captures));
- }
+ if (captures == NULL_TREE)
+ return;
+
+ register_capture_members (TREE_CHAIN (captures));
+ /* We set this in add_capture to avoid duplicates. */
+ IDENTIFIER_MARKED (DECL_NAME (TREE_PURPOSE (captures))) = false;
+ finish_member_declaration (TREE_PURPOSE (captures));
}
/* Similar to add_capture, except this works on a stack of nested lambdas.
new file mode 100644
@@ -0,0 +1,12 @@
+// FDIS 5.1.2/8
+// { dg-options "-pedantic-errors -std=c++0x" }
+
+struct S2 { void f(int i); };
+void S2::f(int i) {
+ [&, i]{ }; // OK
+ [&, &i]{ }; // { dg-error "" } i preceded by & when & is the default
+ [=, i]{ }; // { dg-error "" } i not preceded by & when = is the default
+ [=, this]{ }; // { dg-error "" } this when = is the default
+ [i, i]{ }; // { dg-error "" } i repeated
+ [this, this]{ }; // { dg-error "" } i repeated
+}