================
Comment at: include/clang/Basic/DiagnosticCommonKinds.td:119
@@ +118,3 @@
+ InGroup<ImplicitlyUnsignedLiteral>;
+def warn_old_implicitly_unsigned_long : Warning<
+ "integer literal is of type unsigned long only when %select{C99|C++11}0 "
----------------
hubert.reinterpretcast wrote:
> rsmith wrote:
> > In C++98, this should probably be an `ExtWarn` rather than a `Warning`,
> > because this case has undefined behavior. Splitting this into two warnings
> > would also allow you to put the warning into `-Wc99-compat` or
> > `-Wc++11-compat` as appropriate, and to indicate that the C++98 case has
> > undefined behavior.
> In C++98, the undefined behaviour is only on the case of a decimal integer
> literal with none of `u`/`U`/`l`/`L`. If the `l`/`L` is present, the choice
> of `unsigned long` is required to be considered after `long`.
>
> I agree that an `ExtWarn` is appropriate for the undefined behaviour case,
> but I do not think that the `-Wc99-compat`/`-Wc++11-compat` split still
> follows.
OK, so:
* For the cases where the code has undefined behavior, the warning should be
an `ExtWarn`
* For the cases where the code has defined behavior but changes meaning in a
later standard, the warning should be in `-Wc*-compat`
* For the cases where the code becomes invalid in a later standard, the
warning should say so
* We should split this warning up into enough separate diagnostics that we can
cover all of the above cases with correct, clear, helpful diagnostics
I think the different cases are:
1) C89, no suffix or L, LONG_MAX == LLONG_MAX (c99-compat), "will be
ill-formed in C99 onwards"
2) C89, no suffix or L, LONG_MAX < LLONG_MAX (c99-compat), "will have type
'long long' in C99 onwards"
3) C++98, no suffix, LONG_MAX == LLONG_MAX (c++11-compat, ExtWarn), "will be
ill-formed in C++11 onwards"
4) C++98, L suffix, LONG_MAX == LLONG_MAX (c++11-compat), "will be ill-formed
in C++11 onwards"
5) C++98, no suffix, LONG_MAX < LLONG_MAX (c++11-compat, ExtWarn), "will have
type 'long long' in C++11 onwards"
6) C++98, L suffix, LONG_MAX < LLONG_MAX (c++11-compat), "will have type 'long
long' in C++11 onwards"
I think you can cover the above with three different diagnostics, for 1+2, 3+5,
and 4+6, with a %select in each one selecting on whether 'long long' is large
enough for the literal.
Each of these should be in either `-Wc99-compat` or `-Wc++11-compat` because
the meaning of the program would be different under `-std=c99` or `-std=c++11`,
respectively.
http://reviews.llvm.org/D9794
EMAIL PREFERENCES
http://reviews.llvm.org/settings/panel/emailpreferences/
_______________________________________________
cfe-commits mailing list
[email protected]
http://lists.cs.uiuc.edu/mailman/listinfo/cfe-commits
