0c1e0d63fe
When lambdas were added in C++11 they were banned from unevaluated contexts as a way to avoid needing to deal with them in mangling or SFINAE. This proposal avoids that with a more narrow proposal: lambdas never compare as equivalent (so we don't need to mangle them), and substitution failures within a lambda are hard errors. Lambdas appearing in places that types couldn't previously have been declared introduces various complications; in particular, it seems likely to mean types with no linkage being used more broadly, risking ODR violations. I want to follow up this patch with some related diagnostics. * decl2.c (min_vis_expr_r): Handle LAMBDA_EXPR. * mangle.c (write_expression): Handle LAMBDA_EXPR. * parser.c (cp_parser_lambda_expression): Allow lambdas in unevaluated context. Start the tentative firewall sooner. (cp_parser_lambda_body): Use cp_evaluated. * pt.c (iterative_hash_template_arg): Handle LAMBDA_EXPR. (tsubst_function_decl): Substitute a lambda even if it isn't dependent. (tsubst_lambda_expr): Use cp_evaluated. Always complain. (tsubst_copy_and_build) [LAMBDA_EXPR]: Do nothing if tf_partial. * semantics.c (begin_class_definition): Allow in template parm list. * tree.c (strip_typedefs_expr): Pass through LAMBDA_EXPR. (cp_tree_equal): Handle LAMBDA_EXPR. From-SVN: r266056
5 lines
115 B
C
5 lines
115 B
C
// PR c++/51464
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// { dg-do compile { target c++11 } }
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template<int = sizeof([])> struct A {}; // { dg-error "" }
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