[PATCH] D36368: Fix type printing of array template args

[John McCall via Phabricator via llvm-commits]

rjmccall added inline comments.


================
Comment at: clang/lib/AST/TemplateBase.cpp:109
+  }
+  return true;
+}
----------------
reikdas wrote:
> rjmccall wrote:
> > Hmm.  This seems unnecessarily complex.  Oh, and I think I suggested the comparison wrong for pointer depth.
> > 
> > Is there a case where the following doesn't work?
> > 
> > ```
> > static unsigned getArrayDepth(QualType type) {
> >   unsigned count = 0;
> >   while (const auto *arrayType = type->getAsArrayTypeUnsafe()) {
> >     count++;
> >     type = arrayType->getElementType();
> >   }
> >   return count;
> > }
> > 
> > static bool needsAmpersandOnTemplateArg(QualType paramType, QualType argType,
> >                                         ASTContext &Ctx) {
> >   if (!paramType->isPointerType())
> >     return false;
> >   if (argType->isFunctionType())
> >     return true;
> >   if (argType->isArrayType())
> >     return getArrayDepth(argType) < getArrayDepth(paramType->getPointeeType());
> >   return false;
> > }
> > ```
> Many tests fail with this. 
> 
> For eg., the tests added to `SemaTemplate/temp_arg_nontype_cxx11.cpp`
> 
> 
> ```
> 
> ********************
> FAIL: Clang :: SemaTemplate/temp_arg_nontype_cxx11.cpp (13255 of 27894)
> ******************** TEST 'Clang :: SemaTemplate/temp_arg_nontype_cxx11.cpp' FAILED ********************
> Script:
> --
> : 'RUN: at line 1';   /home/reik/llvm-project/build/bin/clang -cc1 -internal-isystem /home/reik/llvm-project/build/lib/clang/13.0.0/include -nostdsysteminc -fsyntax-only -verify -std=c++11 /home/reik/llvm-project/clang/test/SemaTemplate/temp_arg_nontype_cxx11.cpp
> --
> Exit Code: 1
> 
> Command Output (stderr):
> --
> error: 'error' diagnostics expected but not seen: 
>   File /home/reik/llvm-project/clang/test/SemaTemplate/temp_arg_nontype_cxx11.cpp Line 102: <&kEta,
>   File /home/reik/llvm-project/clang/test/SemaTemplate/temp_arg_nontype_cxx11.cpp Line 103: <&kDes,
>   File /home/reik/llvm-project/clang/test/SemaTemplate/temp_arg_nontype_cxx11.cpp Line 104: <&kEta,
>   File /home/reik/llvm-project/clang/test/SemaTemplate/temp_arg_nontype_cxx11.cpp Line 105: <&kDes,
>   File /home/reik/llvm-project/clang/test/SemaTemplate/temp_arg_nontype_cxx11.cpp Line 106: <&kNull,
>   File /home/reik/llvm-project/clang/test/SemaTemplate/temp_arg_nontype_cxx11.cpp Line 108: <&kZero,
> error: 'error' diagnostics seen but not expected: 
>   File /home/reik/llvm-project/clang/test/SemaTemplate/temp_arg_nontype_cxx11.cpp Line 102: no member named 'ls' in 'Folumn<kEta, double>'
>   File /home/reik/llvm-project/clang/test/SemaTemplate/temp_arg_nontype_cxx11.cpp Line 103: no member named 'ls' in 'Folumn<kDes, double>'
>   File /home/reik/llvm-project/clang/test/SemaTemplate/temp_arg_nontype_cxx11.cpp Line 104: no member named 'ls' in 'Golumn<kEta, double>'
>   File /home/reik/llvm-project/clang/test/SemaTemplate/temp_arg_nontype_cxx11.cpp Line 105: no member named 'ls' in 'Golumn<kDes, double>'
>   File /home/reik/llvm-project/clang/test/SemaTemplate/temp_arg_nontype_cxx11.cpp Line 106: no member named 'ls' in 'Holumn<kNull, double>'
>   File /home/reik/llvm-project/clang/test/SemaTemplate/temp_arg_nontype_cxx11.cpp Line 108: no member named 'ls' in 'Iolumn<kZero, double>'
> 12 errors generated.
> 
> --
> ```
> 
> 
Oh yes, sorry, my logic was quite wrong.  Try this:

```
static bool needsAmpersandOnTemplateArg(QualType paramType, QualType argType,
                                        ASTContext &Ctx) {
  // Generally, if the parameter type is a pointer, we must be taking the address of
  // something and need a &.  However, if the argument is an array, this could be
  // implicit via array-to-pointer decay.
  if (!paramType->isPointerType())
    return false;
  if (argType->isArrayType())
    return getArrayDepth(argType) == getArrayDepth(paramType->getPointeeType());
  return true;
}
```


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D36368/new/

https://reviews.llvm.org/D36368