diff --git a/clang-tools-extra/clang-tidy/modernize/MacroToEnumCheck.h b/clang-tools-extra/clang-tidy/modernize/MacroToEnumCheck.h
--- a/clang-tools-extra/clang-tidy/modernize/MacroToEnumCheck.h
+++ b/clang-tools-extra/clang-tidy/modernize/MacroToEnumCheck.h
@@ -15,6 +15,8 @@
 namespace tidy {
 namespace modernize {
 
+class MacroToEnumCallbacks;
+
 /// Replaces groups of related macros with an unscoped anonymous enum.
 ///
 /// For the user-facing documentation see:
@@ -25,6 +27,11 @@
       : ClangTidyCheck(Name, Context) {}
   void registerPPCallbacks(const SourceManager &SM, Preprocessor *PP,
                            Preprocessor *ModuleExpanderPP) override;
+  void registerMatchers(ast_matchers::MatchFinder *Finder) override;
+  void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
+
+private:
+  MacroToEnumCallbacks *PPCallback{};
 };
 
 } // namespace modernize
diff --git a/clang-tools-extra/clang-tidy/modernize/MacroToEnumCheck.cpp b/clang-tools-extra/clang-tidy/modernize/MacroToEnumCheck.cpp
--- a/clang-tools-extra/clang-tidy/modernize/MacroToEnumCheck.cpp
+++ b/clang-tools-extra/clang-tidy/modernize/MacroToEnumCheck.cpp
@@ -121,6 +121,8 @@
   SourceLocation LastMacroLocation;
 };
 
+} // namespace
+
 class MacroToEnumCallbacks : public PPCallbacks {
 public:
   MacroToEnumCallbacks(MacroToEnumCheck *Check, const LangOptions &LangOptions,
@@ -197,6 +199,8 @@
   // After we've seen everything, issue warnings and fix-its.
   void EndOfMainFile() override;
 
+  void invalidateRange(SourceRange Range);
+
 private:
   void newEnum() {
     if (Enums.empty() || !Enums.back().empty())
@@ -224,6 +228,7 @@
   void checkName(const Token &MacroNameTok);
   void rememberExpressionName(const Token &MacroNameTok);
   void invalidateExpressionNames();
+  void issueDiagnostics();
   void warnMacroEnum(const EnumMacro &Macro) const;
   void fixEnumMacro(const MacroList &MacroList) const;
 
@@ -472,8 +477,20 @@
 }
 
 void MacroToEnumCallbacks::EndOfMainFile() {
-  invalidateExpressionNames();
+    invalidateExpressionNames();
+    issueDiagnostics();
+}
+
+void MacroToEnumCallbacks::invalidateRange(SourceRange Range) {
+  llvm::erase_if(Enums, [Range](const MacroList &MacroList) {
+    return llvm::any_of(MacroList, [Range](const EnumMacro &Macro) {
+      return Macro.Directive->getLocation() >= Range.getBegin() &&
+             Macro.Directive->getLocation() <= Range.getEnd();
+    });
+  });
+}
 
+void MacroToEnumCallbacks::issueDiagnostics() {
   for (const MacroList &MacroList : Enums) {
     if (MacroList.empty())
       continue;
@@ -530,13 +547,57 @@
   Diagnostic << FixItHint::CreateInsertion(End, "};\n");
 }
 
-} // namespace
-
 void MacroToEnumCheck::registerPPCallbacks(const SourceManager &SM,
                                            Preprocessor *PP,
                                            Preprocessor *ModuleExpanderPP) {
-  PP->addPPCallbacks(
-      std::make_unique<MacroToEnumCallbacks>(this, getLangOpts(), SM));
+  auto Callback = std::make_unique<MacroToEnumCallbacks>(this, getLangOpts(), SM);
+  PPCallback = Callback.get();
+  PP->addPPCallbacks(std::move(Callback));
+}
+
+void MacroToEnumCheck::registerMatchers(ast_matchers::MatchFinder *Finder) {
+  using namespace ast_matchers;
+  auto TopLevelDecl = hasParent(translationUnitDecl());
+  Finder->addMatcher(varDecl(TopLevelDecl).bind("top"), this);
+  Finder->addMatcher(functionDecl(TopLevelDecl).bind("top"), this);
+  Finder->addMatcher(recordDecl(TopLevelDecl).bind("top"), this);
+  Finder->addMatcher(typeAliasDecl(TopLevelDecl).bind("top"), this);
+  Finder->addMatcher(functionTemplateDecl(TopLevelDecl).bind("top"), this);
+  Finder->addMatcher(classTemplateDecl(TopLevelDecl).bind("top"), this);
+  Finder->addMatcher(typeAliasTemplateDecl(TopLevelDecl).bind("top"), this);
+}
+
+static bool isValid(SourceRange Range) {
+  return Range.getBegin().isValid() && Range.getEnd().isValid();
+}
+
+static bool empty(SourceRange Range) {
+  return Range.getBegin() == Range.getEnd();
+}
+
+void MacroToEnumCheck::check(
+    const ast_matchers::MatchFinder::MatchResult &Result) {
+  auto *TLDecl = Result.Nodes.getNodeAs<Decl>("top");
+  if (TLDecl == nullptr)
+      return;
+
+  SourceRange Range = TLDecl->getSourceRange();
+  if (auto *TemplateFn = Result.Nodes.getNodeAs<FunctionTemplateDecl>("top")) {
+    if (TemplateFn->isThisDeclarationADefinition() && TemplateFn->hasBody())
+      Range = SourceRange{TemplateFn->getBeginLoc(),
+                          TemplateFn->getUnderlyingDecl()->getBodyRBrace()};
+  }
+
+  if (isValid(Range) && !empty(Range)) {
+    CharSourceRange CharRange =
+        Lexer::makeFileCharRange(CharSourceRange::getTokenRange(Range),
+                                 *Result.SourceManager, getLangOpts());
+    std::string Text =
+        Lexer::getSourceText(CharRange, *Result.SourceManager, getLangOpts())
+            .str();
+
+    PPCallback->invalidateRange(Range);
+  }
 }
 
 } // namespace modernize
diff --git a/clang-tools-extra/test/clang-tidy/checkers/modernize-macro-to-enum.cpp b/clang-tools-extra/test/clang-tidy/checkers/modernize-macro-to-enum.cpp
--- a/clang-tools-extra/test/clang-tidy/checkers/modernize-macro-to-enum.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/modernize-macro-to-enum.cpp
@@ -1,4 +1,4 @@
-// RUN: %check_clang_tidy -std=c++14-or-later %s modernize-macro-to-enum %t -- -- -I%S/Inputs/modernize-macro-to-enum
+// RUN: %check_clang_tidy -std=c++14-or-later %s modernize-macro-to-enum %t -- -- -I%S/Inputs/modernize-macro-to-enum -fno-delayed-template-parsing
 // C++14 or later required for binary literals.
 
 #if 1
@@ -303,3 +303,75 @@
   FN_GREEN(0);
   FN_BLUE(0);
 }
+
+// Ignore macros defined inside a top-level function definition.
+void g(int x)
+{
+  if (x != 0) {
+#define INSIDE1 1
+#define INSIDE2 2
+    if (INSIDE1 > 1) {
+      f();
+    }
+  } else {
+    if (INSIDE2 == 1) {
+      f();
+    }
+  }
+}
+
+// Ignore macros defined inside a top-level function declaration.
+extern void g2(
+#define INSIDE3 3
+#define INSIDE4 4
+);
+
+// Ignore macros defined inside a record (structure) declaration.
+struct S {
+#define INSIDE5 5
+#define INSIDE6 6
+  char storage[INSIDE5];
+};
+class C {
+#define INSIDE7 7
+#define INSIDE8 8
+};
+template <int N>
+#define INSIDE9 9
+bool fn()
+{
+  #define INSIDE10 10
+  return INSIDE9 > 1 || INSIDE10 < N;
+}
+extern int
+#define INSIDE11 11
+v;
+template <int N>
+class C2 {
+public:
+#define INSIDE12 12
+    char storage[N];
+  bool f() {
+    return N > INSIDE12;
+  }
+  bool g();
+};
+template <int N>
+#define INSIDE13 13
+bool C2<N>::g() {
+#define INSIDE14 14
+  return N < INSIDE12 || N > INSIDE13 || INSIDE14 > N;
+};
+template <typename T>
+class C3 {
+  T data;
+};
+template <typename T>
+#define INSIDE15 15
+using Data = C3<T[INSIDE15]>;
+using Data2 =
+#define INSIDE16 16
+    char[INSIDE16];
+constexpr int
+#define INSIDE17 17
+value = INSIDE17;