[PATCH] D49844: [AST] Add a isActuallyImplicitCast() helper to the CastExpr class.

[Roman Lebedev via Phabricator via cfe-commits]

lebedev.ri created this revision.
lebedev.ri added reviewers: rsmith, erichkeane, rjmccall, aaron.ballman.
Herald added a subscriber: cfe-commits.
lebedev.ri added a dependency: D49838: [AST] Sink 'part of explicit cast' down into ImplicitCastExpr.

This is mostly factored out of https://reviews.llvm.org/D48958.
As of https://reviews.llvm.org/D49838, `ImplicitCastExpr` can tell whether it is a part of ExplicitCastExpr group.
But given just the `CastExpr`, one still has to check that it is not `ExplicitCastExpr` itself,
before using `ImplicitCastExpr::getIsPartOfExplicitCast()`.
Thus, it makes sense to factor out it into a helper function in `CastExpr` baseclass.

This indeed does not have tests. Would be happy to add those, if needed and told how to write those.


Repository:
  rC Clang

https://reviews.llvm.org/D49844

Files:
  include/clang/AST/Expr.h


Index: include/clang/AST/Expr.h
===================================================================
--- include/clang/AST/Expr.h
+++ include/clang/AST/Expr.h
@@ -2850,6 +2850,15 @@
     return const_cast<CastExpr *>(this)->getSubExprAsWritten();
   }
 
+  /// There are two global types of casts - implicit and explicit.
+  /// The Explicit cast is something that was directly written in the source
+  /// code. And the implicit cast is expected to be the opposite.
+  /// But in AST, some explicit casts are represented as ExplicitCastExpr plus
+  /// one or more immediate ImplicitCastExpr (i.e. with nothing inbetween).
+  /// This function returns false if this cast is either an ExplicitCastExpr
+  /// itself, or it is a part of the ExplicitCastExpr group.
+  bool isActuallyImplicitCast() const;
+
   /// If this cast applies a user-defined conversion, retrieve the conversion
   /// function that it invokes.
   NamedDecl *getConversionFunction() const;
@@ -3011,6 +3020,14 @@
   }
 };
 
+inline bool CastExpr::isActuallyImplicitCast() const {
+  // If this is an Implicit cast, is it *NOT* a part of Explicit cast group?
+  if (auto *IC = dyn_cast<ImplicitCastExpr>(this))
+    return !IC->getIsPartOfExplicitCast();
+  assert(isa<ExplicitCastExpr>(this) && "it has to be Explicit cast then.");
+  return false; // Explicit cast is clearly not an Implicit cast.
+}
+
 /// CStyleCastExpr - An explicit cast in C (C99 6.5.4) or a C-style
 /// cast in C++ (C++ [expr.cast]), which uses the syntax
 /// (Type)expr. For example: @c (int)f.


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