Index: clang-tidy/bugprone/MisplacedWideningCastCheck.cpp
===================================================================
--- clang-tidy/bugprone/MisplacedWideningCastCheck.cpp
+++ clang-tidy/bugprone/MisplacedWideningCastCheck.cpp
@@ -213,8 +213,9 @@
         dyn_cast<BuiltinType>(CastType->getUnqualifiedDesugaredType());
     const auto *CalcBuiltinType =
         dyn_cast<BuiltinType>(CalcType->getUnqualifiedDesugaredType());
-    if (CastBuiltinType && CalcBuiltinType &&
-        !isFirstWider(CastBuiltinType->getKind(), CalcBuiltinType->getKind()))
+    if (!CastBuiltinType || !CalcBuiltinType)
+      return;
+    if (!isFirstWider(CastBuiltinType->getKind(), CalcBuiltinType->getKind()))
       return;
   }
 
Index: test/clang-tidy/bugprone-misplaced-widening-cast-explicit-only.cpp
===================================================================
--- test/clang-tidy/bugprone-misplaced-widening-cast-explicit-only.cpp
+++ test/clang-tidy/bugprone-misplaced-widening-cast-explicit-only.cpp
@@ -62,3 +62,21 @@
   enum Type {};
   static char *m_fn1() { char p = (Type)(&p - m_fn1()); }
 };
+
+enum DaysEnum {
+  MON,
+  TUE,
+  WED,
+  THR,
+  FRI,
+  SAT,
+  SUN
+};
+
+// Do not warn for int to enum casts.
+void nextDay(DaysEnum day) {
+  if (day < SUN)
+    day = (DaysEnum)(day + 1);
+  if (day < SUN)
+    day = static_cast<DaysEnum>(day + 1);
+}