diff --git a/lib/Checker/BuiltinFunctionChecker.cpp b/lib/Checker/BuiltinFunctionChecker.cpp
index a43a284..1387573 100644
--- a/lib/Checker/BuiltinFunctionChecker.cpp
+++ b/lib/Checker/BuiltinFunctionChecker.cpp
@@ -73,7 +73,7 @@
     SValBuilder& svalBuilder = ValMgr.getSValBuilder();
     DefinedOrUnknownSVal ExtentMatchesSizeArg =
       svalBuilder.evalEQ(state, Extent, Size);
-    state = state->Assume(ExtentMatchesSizeArg, true);
+    state = state->assume(ExtentMatchesSizeArg, true);
 
     C.GenerateNode(state->BindExpr(CE, loc::MemRegionVal(R)));
     return true;