r186128 - Provide a fixit hint for changing '->' to '.' if there is no operator->

[Kaelyn Uhrain]

On Thu, Jul 11, 2013 at 10:16 PM, Nico Weber <thakis at chromium.org> wrote:

> Nice, thanks!
>
> On Thu, Jul 11, 2013 at 3:38 PM, Kaelyn Uhrain <rikka at google.com> wrote:
>
>> Author: rikka
>> Date: Thu Jul 11 17:38:30 2013
>> New Revision: 186128
>>
>> URL: http://llvm.org/viewvc/llvm-project?rev=186128&view=rev
>> Log:
>> Provide a fixit hint for changing '->' to '.' if there is no operator->
>> defined for a class.
>>
>> Modified:
>>     cfe/trunk/lib/Sema/SemaOverload.cpp
>>     cfe/trunk/test/FixIt/fixit.cpp
>>
>> Modified: cfe/trunk/lib/Sema/SemaOverload.cpp
>> URL:
>> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaOverload.cpp?rev=186128&r1=186127&r2=186128&view=diff
>>
>> ==============================================================================
>> --- cfe/trunk/lib/Sema/SemaOverload.cpp (original)
>> +++ cfe/trunk/lib/Sema/SemaOverload.cpp Thu Jul 11 17:38:30 2013
>> @@ -11353,10 +11353,17 @@ Sema::BuildOverloadedArrowExpr(Scope *S,
>>      break;
>>
>>    case OR_No_Viable_Function:
>> -    if (CandidateSet.empty())
>> -      Diag(OpLoc, diag::err_typecheck_member_reference_arrow)
>> -        << Base->getType() << Base->getSourceRange();
>> -    else
>> +    if (CandidateSet.empty()) {
>> +      QualType BaseType = Base->getType();
>> +      if (BaseType->isRecordType() && !BaseType->isPointerType()) {
>> +        Diag(OpLoc, diag::err_typecheck_member_reference_suggestion)
>> +          << BaseType << 1 << Base->getSourceRange()
>> +          << FixItHint::CreateReplacement(OpLoc, ".");
>>
>
> Since this is a fixit on an error, don't you need to fix up the AST? (
> http://clang.llvm.org/docs/InternalsManual.html#fix-it-hints)
>

This is a tricky case because of how operator-> is recursively applied to
it's own result... from what I could tell, recovery would require not just
breaking out of the loop for operator-> in ActOnStartCXXMemberReference but
also telling the parser to start over with the '.' in place of the '->',
which I have no idea how to do from several function-call-layers within
Sema. And I couldn't add the fixit to a note as the internals manual
suggests since there is no note associated with the diagnostic.


>
>> +      } else {
>> +        Diag(OpLoc, diag::err_typecheck_member_reference_arrow)
>> +          << BaseType << Base->getSourceRange();
>> +      }
>> +    } else
>>        Diag(OpLoc, diag::err_ovl_no_viable_oper)
>>          << "operator->" << Base->getSourceRange();
>>      CandidateSet.NoteCandidates(*this, OCD_AllCandidates, Base);
>>
>> Modified: cfe/trunk/test/FixIt/fixit.cpp
>> URL:
>> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/FixIt/fixit.cpp?rev=186128&r1=186127&r2=186128&view=diff
>>
>> ==============================================================================
>> --- cfe/trunk/test/FixIt/fixit.cpp (original)
>> +++ cfe/trunk/test/FixIt/fixit.cpp Thu Jul 11 17:38:30 2013
>> @@ -312,3 +312,15 @@ namespace PR5066 {
>>    template<typename T> struct X {};
>>    X<int *p> x; // expected-error {{type-id cannot have a name}}
>>  }
>> +
>> +namespace PR15045 {
>> +  class Cl0 {
>> +  public:
>> +    int a;
>> +  };
>> +
>> +  int f() {
>> +    Cl0 c;
>> +    return c->a;  // expected-error {{member reference type
>> 'PR15045::Cl0' is not a pointer; maybe you meant to use '.'?}}
>> +  }
>> +}
>>
>>
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>>
>
>
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