Add support for explicit constructor calls in Microsoft mode.

For example: 

class A{ 
public:
  A& operator=(const A& that) {
      if (this != &that) {
          this->A::~A();
          this->A::A(that);  // <=== explicit constructor call.
      }
      return *this;
  }
};

More work will be needed to support an explicit call to a template constructor.

llvm-svn: 123735

2 files changed, 11 insertions, 1 deletions

diff --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp
index 26fdb2e059c..45e0c3377b8 100644
--- a/clang/lib/Sema/SemaExpr.cpp
+++ b/clang/lib/Sema/SemaExpr.cpp
@@ -3902,6 +3902,12 @@ ExprResult Sema::ActOnMemberAccessExpr(Scope *S, Expr *Base,
   if (SS.isSet() && SS.isInvalid())
     return ExprError();
 
+  // Warn about the explicit constructor calls Microsoft extension.
+  if (getLangOptions().Microsoft &&
+      Id.getKind() == UnqualifiedId::IK_ConstructorName)
+    Diag(Id.getSourceRange().getBegin(),
+         diag::ext_ms_explicit_constructor_call);
+
   TemplateArgumentListInfo TemplateArgsBuffer;
 
   // Decompose the name into its component parts.
diff --git a/clang/lib/Sema/SemaOverload.cpp b/clang/lib/Sema/SemaOverload.cpp
index 80ef65e4335..4bb95912e66 100644
--- a/clang/lib/Sema/SemaOverload.cpp
+++ b/clang/lib/Sema/SemaOverload.cpp
@@ -7904,7 +7904,11 @@ Sema::BuildCallToMemberFunction(Scope *S, Expr *MemExprE,
       if (isa<UsingShadowDecl>(Func))
         Func = cast<UsingShadowDecl>(Func)->getTargetDecl();
 
-      if ((Method = dyn_cast<CXXMethodDecl>(Func))) {
+      // Microsoft supports direct constructor calls.
+      if (getLangOptions().Microsoft && isa<CXXConstructorDecl>(Func)) {
+        AddOverloadCandidate(cast<CXXConstructorDecl>(Func), I.getPair(), Args, NumArgs,
+                             CandidateSet);
+      } else if ((Method = dyn_cast<CXXMethodDecl>(Func))) {
         // If explicit template arguments were provided, we can't call a
         // non-template member function.
         if (TemplateArgs)