diff --git a/core/fxge/dib/cfx_imagetransformer.cpp b/core/fxge/dib/cfx_imagetransformer.cpp
index 8e01127b0..f4ce4d915 100644
--- a/core/fxge/dib/cfx_imagetransformer.cpp
+++ b/core/fxge/dib/cfx_imagetransformer.cpp
@@ -315,14 +315,14 @@ bool CFX_ImageTransformer::Continue(IFX_PauseIndicator* pPause) {
   } else if (pDestMask) {
     CalcData cdata = {
         pDestMask.Get(), result2stretch, pSrcMaskBuf,
-        m_Storer.GetBitmap()->m_pAlphaMask->GetPitch(),
+        static_cast<uint32_t>(m_Storer.GetBitmap()->m_pAlphaMask->GetPitch()),
     };
     CalcMask(cdata);
   }
 
   CalcData cdata = {pTransformed.Get(), result2stretch,
                     m_Storer.GetBitmap()->GetBuffer(),
-                    m_Storer.GetBitmap()->GetPitch()};
+                    static_cast<uint32_t>(m_Storer.GetBitmap()->GetPitch())};
   if (m_Storer.GetBitmap()->IsAlphaMask()) {
     CalcAlpha(cdata);
   } else {
diff --git a/core/fxcrt/string_view_template.h b/core/fxcrt/string_view_template.h
index 05694cf24..101253814 100644
--- a/core/fxcrt/string_view_template.h
+++ b/core/fxcrt/string_view_template.h
@@ -231,9 +231,6 @@ inline bool operator<(const T* lhs, const StringViewTemplate<T>& rhs) {
   return rhs > lhs;
 }
 
-extern template class StringViewTemplate<char>;
-extern template class StringViewTemplate<wchar_t>;
-
 using ByteStringView = StringViewTemplate<char>;
 using WideStringView = StringViewTemplate<wchar_t>;
 
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/fpdfsdk/cpdf_annotcontext.cpp b/fpdfsdk/cpdf_annotcontext.cpp
index 20c5fc343..a40cd1eae 100644
--- a/fpdfsdk/cpdf_annotcontext.cpp
+++ b/fpdfsdk/cpdf_annotcontext.cpp
@@ -16,12 +16,12 @@ CPDF_AnnotContext::CPDF_AnnotContext(CPDF_Dictionary* pAnnotDict,
                                      CPDF_Page* pPage,
                                      CPDF_Stream* pStream)
     : m_pAnnotDict(pAnnotDict), m_pPage(pPage) {
-  SetForm(pStream);
+  SetForm_(pStream);
 }
 
 CPDF_AnnotContext::~CPDF_AnnotContext() = default;
 
-void CPDF_AnnotContext::SetForm(CPDF_Stream* pStream) {
+void CPDF_AnnotContext::SetForm_(CPDF_Stream* pStream) {
   if (!pStream)
     return;
 
diff --git a/fpdfsdk/cpdf_annotcontext.h b/fpdfsdk/cpdf_annotcontext.h
index 38cc91e03..7904ae044 100644
--- a/fpdfsdk/cpdf_annotcontext.h
+++ b/fpdfsdk/cpdf_annotcontext.h
@@ -23,7 +23,7 @@ class CPDF_AnnotContext {
                     CPDF_Stream* pStream);
   ~CPDF_AnnotContext();
 
-  void SetForm(CPDF_Stream* pStream);
+  void SetForm_(CPDF_Stream* pStream);
   bool HasForm() const { return !!m_pAnnotForm; }
   CPDF_Form* GetForm() const { return m_pAnnotForm.get(); }
   CPDF_Dictionary* GetAnnotDict() const { return m_pAnnotDict.Get(); }
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/fpdfsdk/fpdf_annot.cpp b/fpdfsdk/fpdf_annot.cpp
index d3bf38d31..e8aea9707 100644
--- a/fpdfsdk/fpdf_annot.cpp
+++ b/fpdfsdk/fpdf_annot.cpp
@@ -389,7 +389,7 @@ FPDFAnnot_AppendObject(FPDF_ANNOTATION annot, FPDF_PAGEOBJECT obj) {
 
   // Get the annotation's corresponding form object for parsing its AP stream.
   if (!pAnnot->HasForm())
-    pAnnot->SetForm(pStream);
+    pAnnot->SetForm_(pStream);
 
   // Check that the object did not come from the same annotation. If this check
   // succeeds, then it is assumed that the object came from
@@ -425,7 +425,7 @@ FPDF_EXPORT int FPDF_CALLCONV FPDFAnnot_GetObjectCount(FPDF_ANNOTATION annot) {
     if (!pStream)
       return 0;
 
-    pAnnot->SetForm(pStream);
+    pAnnot->SetForm_(pStream);
   }
   return pdfium::CollectionSize<int>(*pAnnot->GetForm()->GetPageObjectList());
 }
@@ -442,7 +442,7 @@ FPDFAnnot_GetObject(FPDF_ANNOTATION annot, int index) {
     if (!pStream)
       return nullptr;
 
-    pAnnot->SetForm(pStream);
+    pAnnot->SetForm_(pStream);
   }
 
   return FPDFPageObjectFromCPDFPageObject(