[PATCH v2 5/6] Add a flag to BuildDeclarationNameExpr to not reject invalid decls.

[Kaelyn Takata]

On Wed, Nov 12, 2014 at 3:30 PM, David Blaikie <dblaikie at gmail.com> wrote:

>
>
> On Wed, Nov 5, 2014 at 1:06 PM, Kaelyn Takata <rikka at google.com> wrote:
>
>>
>>
>> On Tue, Nov 4, 2014 at 4:36 PM, David Blaikie <dblaikie at gmail.com> wrote:
>>
>>> It's helpful to either use an enum (which always seems a bit silly) or a
>>> comment (more realistic, especially since you only have to comment that
>>> single caller in attemptRecovery) to describe what the boolean value is for
>>> ("/*AcceptInvalidDecl*/ true").
>>>
>>
>> I've added comments for both boolean values in the call to
>> SemaRef.BuildDeclarationNameExpr from attemptRecovery.
>>
>>>
>>> What's this flag needed/used for?
>>>
>>
>> The flag is needed to get a valid DeclRefExpr during error recovery even
>> when the Decl isn't marked as valid.
>>
>
> Why does this need to be a flag? (what bad things happen if we always
> accept invalid decls?)
>

Setting the flag to always be true breaks tests in
CXX/stmt.stmt/stmt.iter/stmt.ranged/p1.cpp,
SemaCXX/dependent-auto.cpp, SemaCXX/lambda-expressions.cpp,
and SemaObjCXX/instantiate-stmt.mm. It also causes the assertion failure
"cannot request the size of an undeduced or dependent auto type"
in SemaCXX/lambda-expressions.cpp.


>
>> For example, with the full patch set, not having the flag causes the last
>> error of test/SemaCXX/conversion-function.cpp (at line 419) to fail to be
>> typo-corrected. With the flag or without this patchset:
>>
>> ~/llvm/tools/clang/test/SemaCXX/conversion-function.cpp:419:18: error: no
>> member named 'e' in 'PR18234::A'; did you mean simply 'e'?
>>   bool k1 = e == A::e; // expected-error {{no member named 'e'}}
>>                  ^~~~
>>                  e
>> ~/llvm/tools/clang/test/SemaCXX/conversion-function.cpp:418:8: note: 'e'
>> declared here
>>   A::E e = a; // expected-note {{here}}
>>        ^
>> 4 warnings and 26 errors generated.
>>
>> With this patchset but without this flag:
>>
>> ~/llvm/tools/clang/test/SemaCXX/conversion-function.cpp:419:21: error: no
>> member named 'e' in 'PR18234::A'
>>   bool k1 = e == A::e; // expected-error {{no member named 'e'}}
>>                  ~~~^
>> 4 warnings and 26 errors generated.
>>
>>
>>> On Wed, Oct 29, 2014 at 12:49 PM, Kaelyn Takata <rikka at google.com>
>>> wrote:
>>>
>>>> ---
>>>>  include/clang/Sema/Sema.h |  6 ++++--
>>>>  lib/Sema/SemaExpr.cpp     | 15 ++++++++-------
>>>>  lib/Sema/SemaExprCXX.cpp  |  2 +-
>>>>  3 files changed, 13 insertions(+), 10 deletions(-)
>>>>
>>>>
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>>>>
>>>>
>>>
>>
>
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