diff --git a/BUILD.gn b/BUILD.gn
index cb1da47..ca42418 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -288,6 +288,9 @@
       "/wd4577",
     ]
   }
+  if (is_clang) {
+    cflags += [ "-Wcovered-switch-default" ]
+  }
 }
 
 config("pdfium_strict_config") {
diff --git a/core/fxge/skia/fx_skia_device.cpp b/core/fxge/skia/fx_skia_device.cpp
index ef3218d..9ea0b24 100644
--- a/core/fxge/skia/fx_skia_device.cpp
+++ b/core/fxge/skia/fx_skia_device.cpp
@@ -331,7 +331,6 @@
     case BlendMode::kLuminosity:
       return SkBlendMode::kLuminosity;
     case BlendMode::kNormal:
-    default:
       return SkBlendMode::kSrcOver;
   }
 }
diff --git a/fxjs/cjs_field.cpp b/fxjs/cjs_field.cpp
index 867e167..c9127dd 100644
--- a/fxjs/cjs_field.cpp
+++ b/fxjs/cjs_field.cpp
@@ -235,7 +235,7 @@
                     const ByteString& bsString) {
   DCHECK(pFormFillEnv);
 
-  BorderStyle nBorderStyle = BorderStyle::kSolid;
+  BorderStyle nBorderStyle;
   if (bsString == "solid")
     nBorderStyle = BorderStyle::kSolid;
   else if (bsString == "beveled")
@@ -2022,8 +2022,10 @@
       return CJS_Result::Success(pRuntime->NewString("text"));
     case FormFieldType::kSignature:
       return CJS_Result::Success(pRuntime->NewString("signature"));
+#ifdef PDF_ENABLE_XFA
     default:
       return CJS_Result::Success(pRuntime->NewString("unknown"));
+#endif
   }
 }