Added a warning when referencing an if's condition variable in the

"else" clause, e.g.,

  if (int X = foo()) {
  } else {
    if (X) { // warning: X is always zero in this context
    }
  }

Fixes rdar://6425550 and lets me think about something other than
DeclContext.

llvm-svn: 60858

1 files changed, 4 insertions, 0 deletions

diff --git a/clang/lib/Sema/SemaExprCXX.cpp b/clang/lib/Sema/SemaExprCXX.cpp
index c4cab3316ba..27b0ba34d19 100644
--- a/clang/lib/Sema/SemaExprCXX.cpp
+++ b/clang/lib/Sema/SemaExprCXX.cpp
@@ -648,6 +648,10 @@ Sema::ActOnCXXConditionDeclarationExpr(Scope *S, SourceLocation StartLoc,
     return true;
   AddInitializerToDecl(Dcl, AssignExprVal);
 
+  // Mark this variable as one that is declared within a conditional.
+  if (VarDecl *VD = dyn_cast<VarDecl>((Decl *)Dcl))
+    VD->setDeclaredInCondition(true);
+
   return new CXXConditionDeclExpr(StartLoc, EqualLoc,
                                        cast<VarDecl>(static_cast<Decl *>(Dcl)));
 }