| Message ID | 20170630172424.GN2123@tucnak |
|---|---|
| State | New |
| Headers | show |
On 06/30/2017 01:24 PM, Jakub Jelinek wrote: > The initializer for structured binding has to be one of: > = assignment-expression > ( assignment-expression ) > { assignment-expression } > but cp_parser_initializer can parse other forms, with fewer or more > expressions in there. Some cases we caught with various cryptic errors > or pedwarns, but others we just ICEd on. > > The following patch attempts to check this. ok, but ... > --- gcc/testsuite/g++.dg/cpp1z/decomp21.C.jj 2017-01-19 17:01:21.000000000 +0100 > +++ gcc/testsuite/g++.dg/cpp1z/decomp21.C 2017-06-30 11:07:04.786746784 +0200 > @@ -12,5 +12,5 @@ foo () > auto [ n, o, p ] { a }; > auto [ q, r, t ] ( s ); > auto [ u, v, w ] ( s, ); // { dg-error "expected primary-expression before '.' token" } > - auto [ x, y, z ] ( a ); // { dg-error "expression list treated as compound expression in initializer" "" { target *-*-* } .-1 } > + auto [ x, y, z ] ( a ); // { dg-error "invalid initializer for structured binding" "" { target *-*-* } .-1 } > } The .-1 on the final error is actually about the previous statement, not the line it's lexically on. Could you put it on a line on its own, while you're there?
--- gcc/cp/parser.c.jj 2017-06-30 09:49:25.000000000 +0200 +++ gcc/cp/parser.c 2017-06-30 11:03:18.526521000 +0200 @@ -13196,6 +13196,15 @@ cp_parser_decomposition_declaration (cp_ *init_loc = cp_lexer_peek_token (parser->lexer)->location; tree initializer = cp_parser_initializer (parser, &is_direct_init, &non_constant_p); + if (initializer == NULL_TREE + || (TREE_CODE (initializer) == TREE_LIST + && TREE_CHAIN (initializer)) + || (TREE_CODE (initializer) == CONSTRUCTOR + && CONSTRUCTOR_NELTS (initializer) != 1)) + { + error_at (loc, "invalid initializer for structured binding"); + initializer = error_mark_node; + } if (decl != error_mark_node) { --- gcc/testsuite/g++.dg/cpp1z/decomp21.C.jj 2017-01-19 17:01:21.000000000 +0100 +++ gcc/testsuite/g++.dg/cpp1z/decomp21.C 2017-06-30 11:07:04.786746784 +0200 @@ -12,5 +12,5 @@ foo () auto [ n, o, p ] { a }; auto [ q, r, t ] ( s ); auto [ u, v, w ] ( s, ); // { dg-error "expected primary-expression before '.' token" } - auto [ x, y, z ] ( a ); // { dg-error "expression list treated as compound expression in initializer" "" { target *-*-* } .-1 } + auto [ x, y, z ] ( a ); // { dg-error "invalid initializer for structured binding" "" { target *-*-* } .-1 } } --- gcc/testsuite/g++.dg/cpp1z/decomp30.C.jj 2017-06-30 11:09:31.934942575 +0200 +++ gcc/testsuite/g++.dg/cpp1z/decomp30.C 2017-06-30 11:09:22.000000000 +0200 @@ -0,0 +1,12 @@ +// PR c++/81258 +// { dg-options -std=c++1z } + +int a[2]; +auto [b, c] (a); +auto [d, e] { a }; +auto [f, g] = a; +auto [h, i] ( a, a ); // { dg-error "invalid initializer for structured binding" } +auto [j, k] { a, a }; // { dg-error "invalid initializer for structured binding" } +auto [l, m] = { a }; // { dg-error "deducing from brace-enclosed initializer list requires" } +auto [n, o] {}; // { dg-error "invalid initializer for structured binding" } +auto [p, q] (); // { dg-error "invalid initializer for structured binding" }
Hi! The initializer for structured binding has to be one of: = assignment-expression ( assignment-expression ) { assignment-expression } but cp_parser_initializer can parse other forms, with fewer or more expressions in there. Some cases we caught with various cryptic errors or pedwarns, but others we just ICEd on. The following patch attempts to check this. Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk? 2017-06-30 Jakub Jelinek <jakub@redhat.com> PR c++/81258 * parser.c (cp_parser_decomposition_declaration): Diagnose invalid forms of structured binding initializers. * g++.dg/cpp1z/decomp21.C (foo): Adjust expected diagnostics. * g++.dg/cpp1z/decomp30.C: New test. Jakub