A summary of what has been proposed so far to clean up Wextra follows. Please, your feedback is appreciated. And reviewing patches even more ;-)
* Subscripting an array which has been declared register. * Taking the address of a variable which has been declared register. Proposed: new option -Waddress-of-register that is enabled by Wextra. A patch is available here: http://gcc.gnu.org/ml/gcc-patches/2006-12/msg01676.html * A base class is not initialized in a derived class' copy constructor. Proposed: move this warning to -Wuninitialized seems the appropriate solution. However, I am afraid that this warning will turn out to be too noisy and hard to avoid to be in Wuninitialized (see PR 11159). Perhaps a new option -Wuninitialized-base-class enabled by -Wextra would be better if that PR cannot be easily fixed. * A non-static reference or non-static const member appears in a class without constructors. Proposed: move this warning to -Wuninitialized * Ambiguous virtual bases (virtual base inaccessible due to ambiguity). Proposed: move this warning to -Woverloaded-virtual * An enumerator and a non-enumerator both appear in a conditional expression. Proposed: move this warning to (the new) -Wconversion * A function can return either with or without a value. This is warned already by Wreturn-type: "'return' with no value, in function returning non-void" and I wasn't able to come up with a testcase that is warned by Wextra but not by Wreturn-type. Proposed: move to Wreturn-type whatever is not there yet. * An expression-statement or the left-hand side of a comma expression contains no side effects. For example, an expression such as x[i,j]. This is also warned by Wunused-value. In addition, Wextra enables Wunused-value but this is not documented (and -Wunused-value is already enabled by -Wall). Proposed: Wextra should not enable Wunused-value. Patch: http://gcc.gnu.org/ml/gcc-patches/2007-01/msg00440.html * A pointer is compared against integer zero with <, <=, >, or >=. This is a pedwarn and it can also be enabled by using -pedantic. If the pointer is the rightmost operator, there is no warning for Wextra (surely a bug). Proposed: Fix the bug. a) Enable the warning with -pedantic or -Wpointer-arith; or b) Enable the warning with -pedantic or its own option -Wordered-pointer-comparison (which would be enabled by Wextra). There is a patch for option (b): http://gcc.gnu.org/ml/gcc-patches/2007-01/msg00608.html * In ./gcc/config/sh/symbian.c:158 there is a warning enabled by Wextra but conditional on Wattributes. Proposed: drop the test for Wextra. * The manual page claims that Wextra warns for any of several floating-point events that often indicate errors, such as overflow, underflow, loss of precision, etc. I wasn't able to find any instance of this. I am fairly sure that Wextra doesn't do such thing. Proposed: remove text from doc/invoke.texi * In Java, Wextra warns for unreachable bytecode. Proposed: a) This should be warned by -Wunreachable-code or b) a new option -Wunreachable-bytecode that is enabled by Wextra. * An unsigned value is compared against zero with < or >=. There is also an unconditional warning for expressions that are always true or false due to the range of types. Proposal: my proposal is a new option that takes over both warnings and is enabled by Wextra. A patch is available at http://gcc.gnu.org/ml/gcc-patches/2007-01/msg01933.html That is a lot to do! Well, I hope you find some time to make some suggestions. Cheers, Manuel.
