diff --git a/clang/lib/StaticAnalyzer/Core/CallEvent.cpp b/clang/lib/StaticAnalyzer/Core/CallEvent.cpp
index 0fdef7487b981..bb4a39f68280c 100644
--- a/clang/lib/StaticAnalyzer/Core/CallEvent.cpp
+++ b/clang/lib/StaticAnalyzer/Core/CallEvent.cpp
@@ -435,27 +435,27 @@ static SVal processArgument(SVal Value, const Expr *ArgumentExpr,
 /// runtime definition don't match in terms of argument and parameter count.
 static SVal castArgToParamTypeIfNeeded(const CallEvent &Call, unsigned ArgIdx,
                                        SVal ArgVal, SValBuilder &SVB) {
-  const FunctionDecl *RTDecl =
-      Call.getRuntimeDefinition().getDecl()->getAsFunction();
   const auto *CallExprDecl = dyn_cast_or_null<FunctionDecl>(Call.getDecl());
-
-  if (!RTDecl || !CallExprDecl)
+  if (!CallExprDecl)
     return ArgVal;
 
+  const FunctionDecl *Definition = CallExprDecl;
+  Definition->hasBody(Definition);
+
   // The function decl of the Call (in the AST) will not have any parameter
   // declarations, if it was 'only' declared without a prototype. However, the
   // engine will find the appropriate runtime definition - basically a
   // redeclaration, which has a function body (and a function prototype).
-  if (CallExprDecl->hasPrototype() || !RTDecl->hasPrototype())
+  if (CallExprDecl->hasPrototype() || !Definition->hasPrototype())
     return ArgVal;
 
   // Only do this cast if the number arguments at the callsite matches with
   // the parameters at the runtime definition.
-  if (Call.getNumArgs() != RTDecl->getNumParams())
+  if (Call.getNumArgs() != Definition->getNumParams())
     return UnknownVal();
 
   const Expr *ArgExpr = Call.getArgExpr(ArgIdx);
-  const ParmVarDecl *Param = RTDecl->getParamDecl(ArgIdx);
+  const ParmVarDecl *Param = Definition->getParamDecl(ArgIdx);
   return SVB.evalCast(ArgVal, Param->getType(), ArgExpr->getType());
 }