diff --git a/core/fpdfapi/edit/cpdf_pagecontentgenerator.cpp b/core/fpdfapi/edit/cpdf_pagecontentgenerator.cpp
index 7654bc1..5ed2414 100644
--- a/core/fpdfapi/edit/cpdf_pagecontentgenerator.cpp
+++ b/core/fpdfapi/edit/cpdf_pagecontentgenerator.cpp
@@ -361,9 +361,8 @@
         *buf << "/" << item->GetPropertyName() << " ";
         break;
       }
-      default:
-        NOTREACHED();
-        break;
+      case CPDF_ContentMarkItem::kNone:
+        NOTREACHED_NORETURN();
     }
 
     // Write BDC (begin dictionary content) operator.
@@ -573,8 +572,7 @@
           *buf << " W* ";
           break;
         case CFX_FillRenderOptions::FillType::kNoFill:
-          NOTREACHED();
-          break;
+          NOTREACHED_NORETURN();
       }
 
       // Use a no-op path-painting operator to terminate the path without
diff --git a/core/fpdfapi/edit/cpdf_stringarchivestream.cpp b/core/fpdfapi/edit/cpdf_stringarchivestream.cpp
index 4d9f7f2..48033b0 100644
--- a/core/fpdfapi/edit/cpdf_stringarchivestream.cpp
+++ b/core/fpdfapi/edit/cpdf_stringarchivestream.cpp
@@ -14,8 +14,7 @@
 CPDF_StringArchiveStream::~CPDF_StringArchiveStream() = default;
 
 FX_FILESIZE CPDF_StringArchiveStream::CurrentOffset() const {
-  NOTREACHED();
-  return false;
+  NOTREACHED_NORETURN();
 }
 
 bool CPDF_StringArchiveStream::WriteBlock(pdfium::span<const uint8_t> buffer) {
diff --git a/core/fpdfapi/font/cfx_stockfontarray.cpp b/core/fpdfapi/font/cfx_stockfontarray.cpp
index b6793ff..3142525 100644
--- a/core/fpdfapi/font/cfx_stockfontarray.cpp
+++ b/core/fpdfapi/font/cfx_stockfontarray.cpp
@@ -11,7 +11,7 @@
 
 #include "core/fpdfapi/font/cpdf_font.h"
 #include "core/fpdfapi/parser/cpdf_dictionary.h"
-#include "third_party/base/notreached.h"
+#include "third_party/base/check_op.h"
 
 CFX_StockFontArray::CFX_StockFontArray() = default;
 
@@ -29,10 +29,8 @@
 
 RetainPtr<CPDF_Font> CFX_StockFontArray::GetFont(
     CFX_FontMapper::StandardFont index) const {
-  if (index < std::size(m_StockFonts))
-    return m_StockFonts[index];
-  NOTREACHED();
-  return nullptr;
+  CHECK_LT(index, std::size(m_StockFonts));
+  return m_StockFonts[index];
 }
 
 void CFX_StockFontArray::SetFont(CFX_FontMapper::StandardFont index,
diff --git a/core/fpdfdoc/cpdf_defaultappearance.cpp b/core/fpdfdoc/cpdf_defaultappearance.cpp
index 1eda1d9..63eba37 100644
--- a/core/fpdfdoc/cpdf_defaultappearance.cpp
+++ b/core/fpdfdoc/cpdf_defaultappearance.cpp
@@ -135,8 +135,7 @@
                    static_cast<int>(g * 255 + 0.5f),
                    static_cast<int>(b * 255 + 0.5f)));
   }
-  NOTREACHED();
-  return absl::nullopt;
+  NOTREACHED_NORETURN();
 }
 
 // static
diff --git a/core/fpdfdoc/cpvt_fontmap.cpp b/core/fpdfdoc/cpvt_fontmap.cpp
index d26655f..b492b5f 100644
--- a/core/fpdfdoc/cpvt_fontmap.cpp
+++ b/core/fpdfdoc/cpvt_fontmap.cpp
@@ -77,17 +77,14 @@
 int32_t CPVT_FontMap::GetWordFontIndex(uint16_t word,
                                        FX_Charset charset,
                                        int32_t nFontIndex) {
-  NOTREACHED();
-  return 0;
+  NOTREACHED_NORETURN();
 }
 
 int32_t CPVT_FontMap::CharCodeFromUnicode(int32_t nFontIndex, uint16_t word) {
-  NOTREACHED();
-  return 0;
+  NOTREACHED_NORETURN();
 }
 
 FX_Charset CPVT_FontMap::CharSetFromUnicode(uint16_t word,
                                             FX_Charset nOldCharset) {
-  NOTREACHED();
-  return FX_Charset::kANSI;
+  NOTREACHED_NORETURN();
 }