Remove 'AnalysisContext::setDecl()', as we the Decl associated with an
AnalysisContext should never change. Along the way, propagate some constness
around.

llvm-svn: 79701
diff --git a/clang/lib/Analysis/CheckObjCUnusedIVars.cpp b/clang/lib/Analysis/CheckObjCUnusedIVars.cpp
index 3a69e00..7547097 100644
--- a/clang/lib/Analysis/CheckObjCUnusedIVars.cpp
+++ b/clang/lib/Analysis/CheckObjCUnusedIVars.cpp
@@ -62,7 +62,8 @@
     I->second = Used;
 }
 
-void clang::CheckObjCUnusedIvar(ObjCImplementationDecl* D, BugReporter& BR) {
+void clang::CheckObjCUnusedIvar(const ObjCImplementationDecl *D,
+                                BugReporter &BR) {
 
   const ObjCInterfaceDecl* ID = D->getClassInterface();
   IvarUsageMap M;