diff --git a/core/fpdfdoc/cpdf_metadata.cpp b/core/fpdfdoc/cpdf_metadata.cpp
index 323de4ffc..f11a0b0ad 100644
--- a/core/fpdfdoc/cpdf_metadata.cpp
+++ b/core/fpdfdoc/cpdf_metadata.cpp
@@ -74,7 +74,7 @@ std::vector<UnsupportedFeature> CPDF_Metadata::CheckForSharedForm() const {
   CFX_XMLParser parser(stream);
   std::unique_ptr<CFX_XMLDocument> doc = parser.Parse();
   if (!doc)
-    return {};
+    return std::vector<UnsupportedFeature>();
 
   std::vector<UnsupportedFeature> unsupported;
   CheckForSharedFormInternal(doc->GetRoot(), &unsupported);
diff --git a/third_party/base/span.h b/third_party/base/span.h
index 0fb627ba8..f71c362e2 100644
--- a/third_party/base/span.h
+++ b/third_party/base/span.h
@@ -214,7 +214,7 @@ class span {
   // Conversions from spans of compatible types: this allows a span<T> to be
   // seamlessly used as a span<const T>, but not the other way around.
   template <typename U, typename = internal::EnableIfLegalSpanConversion<U, T>>
-  constexpr span(const span<U>& other) : span(other.data(), other.size()) {}
+  span(const span<U>& other) : span(other.data(), other.size()) {}
   span& operator=(const span& other) noexcept = default;
   ~span() noexcept {
     if (!size_) {
diff --git a/third_party/base/span.h b/third_party/base/span.h
index 0fb627ba8..dda1fc8bc 100644
--- a/third_party/base/span.h
+++ b/third_party/base/span.h
@@ -204,7 +204,7 @@ class span {
   // size()|.
   template <typename Container,
             typename = internal::EnableIfSpanCompatibleContainer<Container, T>>
-  constexpr span(Container& container)
+  span(Container& container)
       : span(container.data(), container.size()) {}
   template <
       typename Container,
--- a/core/fxcrt/fx_memory_wrappers.h.orig	2020-01-15 11:16:03.848760100 +0100
+++ b/core/fxcrt/fx_memory_wrappers.h	2020-01-15 11:16:44.050531200 +0100
@@ -23,8 +23,11 @@
 template <class T>
 struct FxAllocAllocator {
  public:
+#ifndef _WIN32
+  // MSVC thinks uint8_t is not an arithmetic type.
   static_assert(std::is_arithmetic<T>::value,
                 "Only numeric types allowed in this partition");
+#endif
 
   using value_type = T;
   using pointer = T*;