Code-comment mismatch in `AutoType::getDeducedType`

[llvmbot]

Bugzilla Link	20215
Version	trunk
OS	All
Reporter	LLVM Bugzilla Contributor

Extended Description

The code in clang\AST\Type.h:3678 for AutoType reads:

  /// \brief Get the type deduced for this auto type, or null if it's either
  /// not been deduced or was deduced to a dependent type.
  QualType getDeducedType() const {
    return !isCanonicalUnqualified() ? getCanonicalTypeInternal() : QualType();
  }
  bool isDeduced() const {
    return !isCanonicalUnqualified() || isDependentType();
  }

the comment does not seem to match the logic of getDeducedType.

Either the code needs to be

  QualType getDeducedType() const {
    return isDeduced() ? getCanonicalTypeInternal() : QualType();
  }

or the comment changed, I'm not sure.

[llvmbot]

the code is now in DeducedType, clang\AST\Type.h:4190 but the issue is identical.

[AaronBallman]

The comment was updated at some point and now seems reasonable:

  /// Get the type deduced for this placeholder type, or null if it
  /// has not been deduced.
  QualType getDeducedType() const { return DeducedAsType; }
  bool isDeduced() const {
    return !DeducedAsType.isNull() || isDependentType();
  }

There's also a class-level comment which helps:

/// These types are usually a placeholder for a deduced type. However, before
/// the initializer is attached, or (usually) if the initializer is
/// type-dependent, there is no deduced type and the type is canonical. In
/// the latter case, it is also a dependent type.

So I believe this issue can be closed.

[llvmbot]

@llvm/issue-subscribers-clang-frontend

Author: None (llvmbot)

| | | | --- | --- | | Bugzilla Link | [20215](https://llvm.org/bz20215) | | Version | trunk | | OS | All | | Reporter | LLVM Bugzilla Contributor |

Extended Description

The code in clang\AST\Type.h:3678 for AutoType reads:

  /// \brief Get the type deduced for this auto type, or null if it's either
  /// not been deduced or was deduced to a dependent type.
  QualType getDeducedType() const {
    return !isCanonicalUnqualified() ? getCanonicalTypeInternal() : QualType();
  }
  bool isDeduced() const {
    return !isCanonicalUnqualified() || isDependentType();
  }

the comment does not seem to match the logic of getDeducedType.

Either the code needs to be

  QualType getDeducedType() const {
    return isDeduced() ? getCanonicalTypeInternal() : QualType();
  }

or the comment changed, I'm not sure.