[cfe-dev] Function Arg Type not expected

[Daniel Dilts via cfe-dev]

You are right that all it does have the implicit cast to const, but all
three have an implicit cast to const that are notated as <NoOp>.  So, that
doesn't appear to be what is causing my issues.

On Wed, Jun 15, 2016 at 7:29 PM, don hinton <hintonda at gmail.com> wrote:

> If you dump the ast, -Xclang -ast-dump -fsyntax-only, you'll see that when
> s is passed by value, an ImplicitCastExpr node is created for the implicit
> type conversion from "struct S<int>" to "const struct S<int>", and you are
> ignoring implicits,  IgnoreImplicit():
>
>     |-CallExpr 0x7fefab076990 <line:44:3, col:9> 'void'
>     | |-ImplicitCastExpr 0x7fefab076978 <col:3> 'void (*)(struct S<int>)'
> <FunctionToPointerDecay>
>     | | `-DeclRefExpr 0x7fefab0768e8 <col:3> 'void (struct S<int>)' lvalue
> Function 0x7fefab0767e0 'Func' 'void (struct S<int>)' (FunctionTemplate
> 0x7fefab06e808 'Func')
>     | `-CXXConstructExpr 0x7fefab076a28 <col:8> 'struct S<int>':'struct
> S<int>' 'void (const struct S<int> &) throw()'
>     |   `-ImplicitCastExpr 0x7fefab0769c0 <col:8> 'const struct S<int>'
> lvalue <NoOp>
>     |     `-DeclRefExpr 0x7fefab0765b8 <col:8> 'S<int>':'struct S<int>'
> lvalue Var 0x7fefab06ee48 's' 'S<int>':'struct S<int>'
>
> If you made s const instead, i.e., const S<int> s, then clang wouldn't
> need to implicitly convert it and you should see it.
>
> hth...
> don
>
> On Wed, Jun 15, 2016 at 5:21 PM, Daniel Dilts via cfe-dev <
> cfe-dev at lists.llvm.org> wrote:
>
>> I am writing a tool using the 3.8.0 source code.  My ASTMatcher is
>> callExpr().bind("callExpr");  I am getting the type of the first argument
>> with auto type = callExpr->getArg(i)->IgnoreImplicit()->getType();
>>
>> Given this code:
>>
>> template <typename>
>> struct S{};
>>
>> void Func2()
>> {
>>  S<int> s;
>>  Func(s);
>> }
>>
>> If Func is declared as either of these, then
>> type->getAs<TemplateSpecializationType>() returns a non-null value and
>> type.getAsString() returns "S<int>":
>>
>> void Func(...);
>>
>> template <typename T>
>> void Func(const T&);
>>
>> If Func is declared as this, then
>> type->getAs<TemplateSpecializationType>() returns null and
>> type.getAsString() returns "struct S<int>":
>>
>> template <typename T>
>> void Func(T);
>>
>>
>>
>> I would expect all three to return a non-null value and the same result
>> from getAsString.  Why do these differ?
>>
>> _______________________________________________
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>>
>>
>
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