Index: lib/StaticAnalyzer/Core/CallEvent.cpp
===================================================================
--- lib/StaticAnalyzer/Core/CallEvent.cpp
+++ lib/StaticAnalyzer/Core/CallEvent.cpp
@@ -425,6 +425,9 @@
   SVal ThisVal = getCXXThisVal();
   Values.push_back(ThisVal);
 
+  if (ThisVal.isUnknown())
+    return;
+
   // Don't invalidate if the method is const and there are no mutable fields.
   if (const CXXMethodDecl *D = cast_or_null<CXXMethodDecl>(getDecl())) {
     if (!D->isConst())
Index: test/Analysis/const-method-call.cpp
===================================================================
--- test/Analysis/const-method-call.cpp
+++ test/Analysis/const-method-call.cpp
@@ -204,6 +204,28 @@
     s2().f(0);
 }
 
+// --- PR25392 --- //
+
+struct x0;
+template <typename> struct x1 {
+  typedef x0 x2;
+};
+
+template <typename x3, typename x4 = x3> struct x5 {
+public:
+  typename x1<x4>::x2 operator[](int) {} // expected-warning {{control reaches end of non-void function}}
+};
+
+struct x0 {
+public:
+  template <typename> void x6() const;
+  x5<int> x7;
+} x8;
+
+void x9() {
+  x8.x7[0].x6<x5<int> >(); // expected-note {{in instantiation of member function 'x5<int, int>::operator[]' requested here}}
+}
+
 // FIXME
 // When there is a circular reference to an object and a const method is called
 // the object is not invalidated because TK_PreserveContents has already been