[Bug c++/44062] (void)var; doesn't prevent 'set but not used' warning

[jakub at gcc dot gnu dot org]

------- Comment #5 from jakub at gcc dot gnu dot org  2010-05-11 18:12 -------
Subject: Bug 44062

Author: jakub
Date: Tue May 11 18:12:28 2010
New Revision: 159286

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=159286
Log:
        PR c++/44062
        * c-parser.c (c_parser_expression): Mark LHS of a comma
        expression as read if it is a decl, handled component or
        COMPOUND_EXPR with that on the RHS.
        * c-typeck.c (c_process_expr_stmt): Mark RHS of COMPOUND_EXPR
        if it is a decl or handled component.

        * semantics.c (finish_expr_stmt): Don't call mark_exp_read here...
        * cvt.c (convert_to_void): ... but here.  If expr is a COMPOUND_EXPR,
        look at its second operand.

        * c-c++-common/Wunused-var-7.c: New test.
        * g++.dg/warn/Wunused-var-9.C: New test.

Added:
    trunk/gcc/testsuite/c-c++-common/Wunused-var-7.c
    trunk/gcc/testsuite/g++.dg/warn/Wunused-var-9.C
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/c-parser.c
    trunk/gcc/c-typeck.c
    trunk/gcc/cp/ChangeLog
    trunk/gcc/cp/cvt.c
    trunk/gcc/cp/semantics.c
    trunk/gcc/testsuite/ChangeLog


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44062