Improve comments.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@120142 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Checker/Environment.cpp b/lib/Checker/Environment.cpp
index 0bbe40d..b09cb9d 100644
--- a/lib/Checker/Environment.cpp
+++ b/lib/Checker/Environment.cpp
@@ -53,8 +53,7 @@
           return ValMgr.makeIntVal(cast<IntegerLiteral>(E));
       }
 
-      // Casts where the source and target type are the same
-      // are no-ops.  We blast through these to get the descendant
+      // We blast through no-op casts to get the descendant
       // subexpression that has a value.
 
       case Stmt::ImplicitCastExprClass: