diff --git a/clang/include/clang/Sema/EnterExpressionEvaluationContext.h b/clang/include/clang/Sema/EnterExpressionEvaluationContext.h
new file mode 100644
--- /dev/null
+++ b/clang/include/clang/Sema/EnterExpressionEvaluationContext.h
@@ -0,0 +1,69 @@
+//===--- Sema.h - Semantic Analysis & AST Building --------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_SEMA_ENTEREXPRESSIONEVALUATIONCONTEXT_H
+#define LLVM_CLANG_SEMA_ENTEREXPRESSIONEVALUATIONCONTEXT_H
+
+#include "clang/Sema/Sema.h"
+
+namespace clang {
+
+class Decl;
+
+/// RAII object that enters a new expression evaluation context.
+class EnterExpressionEvaluationContext {
+  Sema &Actions;
+  bool Entered = true;
+
+public:
+  EnterExpressionEvaluationContext(
+      Sema &Actions, Sema::ExpressionEvaluationContext NewContext,
+      Decl *LambdaContextDecl = nullptr,
+      Sema::ExpressionEvaluationContextRecord::ExpressionKind ExprContext =
+          Sema::ExpressionEvaluationContextRecord::EK_Other,
+      bool ShouldEnter = true)
+      : Actions(Actions), Entered(ShouldEnter) {
+    if (Entered)
+      Actions.PushExpressionEvaluationContext(NewContext, LambdaContextDecl,
+                                              ExprContext);
+  }
+  EnterExpressionEvaluationContext(
+      Sema &Actions, Sema::ExpressionEvaluationContext NewContext,
+      Sema::ReuseLambdaContextDecl_t,
+      Sema::ExpressionEvaluationContextRecord::ExpressionKind ExprContext =
+          Sema::ExpressionEvaluationContextRecord::EK_Other)
+      : Actions(Actions) {
+    Actions.PushExpressionEvaluationContext(
+        NewContext, Sema::ReuseLambdaContextDecl, ExprContext);
+  }
+
+  enum InitListTag { InitList };
+  EnterExpressionEvaluationContext(Sema &Actions, InitListTag,
+                                   bool ShouldEnter = true)
+      : Actions(Actions), Entered(false) {
+    // In C++11 onwards, narrowing checks are performed on the contents of
+    // braced-init-lists, even when they occur within unevaluated operands.
+    // Therefore we still need to instantiate constexpr functions used in such
+    // a context.
+    if (ShouldEnter && Actions.isUnevaluatedContext() &&
+        Actions.getLangOpts().CPlusPlus11) {
+      Actions.PushExpressionEvaluationContext(
+          Sema::ExpressionEvaluationContext::UnevaluatedList);
+      Entered = true;
+    }
+  }
+
+  ~EnterExpressionEvaluationContext() {
+    if (Entered)
+      Actions.PopExpressionEvaluationContext();
+  }
+};
+
+} // namespace clang
+
+#endif
\ No newline at end of file
diff --git a/clang/include/clang/Sema/Sema.h b/clang/include/clang/Sema/Sema.h
--- a/clang/include/clang/Sema/Sema.h
+++ b/clang/include/clang/Sema/Sema.h
@@ -13973,55 +13973,6 @@
                                   ValueDecl *DeclToCheck);
 };
 
-/// RAII object that enters a new expression evaluation context.
-class EnterExpressionEvaluationContext {
-  Sema &Actions;
-  bool Entered = true;
-
-public:
-  EnterExpressionEvaluationContext(
-      Sema &Actions, Sema::ExpressionEvaluationContext NewContext,
-      Decl *LambdaContextDecl = nullptr,
-      Sema::ExpressionEvaluationContextRecord::ExpressionKind ExprContext =
-          Sema::ExpressionEvaluationContextRecord::EK_Other,
-      bool ShouldEnter = true)
-      : Actions(Actions), Entered(ShouldEnter) {
-    if (Entered)
-      Actions.PushExpressionEvaluationContext(NewContext, LambdaContextDecl,
-                                              ExprContext);
-  }
-  EnterExpressionEvaluationContext(
-      Sema &Actions, Sema::ExpressionEvaluationContext NewContext,
-      Sema::ReuseLambdaContextDecl_t,
-      Sema::ExpressionEvaluationContextRecord::ExpressionKind ExprContext =
-          Sema::ExpressionEvaluationContextRecord::EK_Other)
-      : Actions(Actions) {
-    Actions.PushExpressionEvaluationContext(
-        NewContext, Sema::ReuseLambdaContextDecl, ExprContext);
-  }
-
-  enum InitListTag { InitList };
-  EnterExpressionEvaluationContext(Sema &Actions, InitListTag,
-                                   bool ShouldEnter = true)
-      : Actions(Actions), Entered(false) {
-    // In C++11 onwards, narrowing checks are performed on the contents of
-    // braced-init-lists, even when they occur within unevaluated operands.
-    // Therefore we still need to instantiate constexpr functions used in such
-    // a context.
-    if (ShouldEnter && Actions.isUnevaluatedContext() &&
-        Actions.getLangOpts().CPlusPlus11) {
-      Actions.PushExpressionEvaluationContext(
-          Sema::ExpressionEvaluationContext::UnevaluatedList);
-      Entered = true;
-    }
-  }
-
-  ~EnterExpressionEvaluationContext() {
-    if (Entered)
-      Actions.PopExpressionEvaluationContext();
-  }
-};
-
 DeductionFailureInfo
 MakeDeductionFailureInfo(ASTContext &Context, Sema::TemplateDeductionResult TDK,
                          sema::TemplateDeductionInfo &Info);
diff --git a/clang/lib/Parse/ParseAST.cpp b/clang/lib/Parse/ParseAST.cpp
--- a/clang/lib/Parse/ParseAST.cpp
+++ b/clang/lib/Parse/ParseAST.cpp
@@ -18,6 +18,7 @@
 #include "clang/Parse/ParseDiagnostic.h"
 #include "clang/Parse/Parser.h"
 #include "clang/Sema/CodeCompleteConsumer.h"
+#include "clang/Sema/EnterExpressionEvaluationContext.h"
 #include "clang/Sema/Sema.h"
 #include "clang/Sema/SemaConsumer.h"
 #include "clang/Sema/TemplateInstCallback.h"
diff --git a/clang/lib/Parse/ParseCXXInlineMethods.cpp b/clang/lib/Parse/ParseCXXInlineMethods.cpp
--- a/clang/lib/Parse/ParseCXXInlineMethods.cpp
+++ b/clang/lib/Parse/ParseCXXInlineMethods.cpp
@@ -10,12 +10,14 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "clang/Parse/Parser.h"
 #include "clang/AST/DeclTemplate.h"
 #include "clang/Parse/ParseDiagnostic.h"
+#include "clang/Parse/Parser.h"
 #include "clang/Parse/RAIIObjectsForParser.h"
 #include "clang/Sema/DeclSpec.h"
+#include "clang/Sema/EnterExpressionEvaluationContext.h"
 #include "clang/Sema/Scope.h"
+
 using namespace clang;
 
 /// ParseCXXInlineMethodDef - We parsed and verified that the specified
diff --git a/clang/lib/Parse/ParseDecl.cpp b/clang/lib/Parse/ParseDecl.cpp
--- a/clang/lib/Parse/ParseDecl.cpp
+++ b/clang/lib/Parse/ParseDecl.cpp
@@ -21,6 +21,7 @@
 #include "clang/Parse/ParseDiagnostic.h"
 #include "clang/Parse/Parser.h"
 #include "clang/Parse/RAIIObjectsForParser.h"
+#include "clang/Sema/EnterExpressionEvaluationContext.h"
 #include "clang/Sema/Lookup.h"
 #include "clang/Sema/ParsedTemplate.h"
 #include "clang/Sema/Scope.h"
diff --git a/clang/lib/Parse/ParseDeclCXX.cpp b/clang/lib/Parse/ParseDeclCXX.cpp
--- a/clang/lib/Parse/ParseDeclCXX.cpp
+++ b/clang/lib/Parse/ParseDeclCXX.cpp
@@ -23,6 +23,7 @@
 #include "clang/Parse/Parser.h"
 #include "clang/Parse/RAIIObjectsForParser.h"
 #include "clang/Sema/DeclSpec.h"
+#include "clang/Sema/EnterExpressionEvaluationContext.h"
 #include "clang/Sema/ParsedTemplate.h"
 #include "clang/Sema/Scope.h"
 #include "llvm/ADT/SmallString.h"
diff --git a/clang/lib/Parse/ParseExpr.cpp b/clang/lib/Parse/ParseExpr.cpp
--- a/clang/lib/Parse/ParseExpr.cpp
+++ b/clang/lib/Parse/ParseExpr.cpp
@@ -20,12 +20,13 @@
 ///
 //===----------------------------------------------------------------------===//
 
-#include "clang/Parse/Parser.h"
 #include "clang/AST/ASTContext.h"
 #include "clang/AST/ExprCXX.h"
 #include "clang/Basic/PrettyStackTrace.h"
+#include "clang/Parse/Parser.h"
 #include "clang/Parse/RAIIObjectsForParser.h"
 #include "clang/Sema/DeclSpec.h"
+#include "clang/Sema/EnterExpressionEvaluationContext.h"
 #include "clang/Sema/ParsedTemplate.h"
 #include "clang/Sema/Scope.h"
 #include "clang/Sema/TypoCorrection.h"
diff --git a/clang/lib/Parse/ParseExprCXX.cpp b/clang/lib/Parse/ParseExprCXX.cpp
--- a/clang/lib/Parse/ParseExprCXX.cpp
+++ b/clang/lib/Parse/ParseExprCXX.cpp
@@ -20,6 +20,7 @@
 #include "clang/Parse/Parser.h"
 #include "clang/Parse/RAIIObjectsForParser.h"
 #include "clang/Sema/DeclSpec.h"
+#include "clang/Sema/EnterExpressionEvaluationContext.h"
 #include "clang/Sema/ParsedTemplate.h"
 #include "clang/Sema/Scope.h"
 #include "llvm/Support/Compiler.h"
diff --git a/clang/lib/Parse/ParseInit.cpp b/clang/lib/Parse/ParseInit.cpp
--- a/clang/lib/Parse/ParseInit.cpp
+++ b/clang/lib/Parse/ParseInit.cpp
@@ -15,6 +15,7 @@
 #include "clang/Parse/Parser.h"
 #include "clang/Parse/RAIIObjectsForParser.h"
 #include "clang/Sema/Designator.h"
+#include "clang/Sema/EnterExpressionEvaluationContext.h"
 #include "clang/Sema/Ownership.h"
 #include "clang/Sema/Scope.h"
 #include "llvm/ADT/STLExtras.h"
diff --git a/clang/lib/Parse/ParseOpenMP.cpp b/clang/lib/Parse/ParseOpenMP.cpp
--- a/clang/lib/Parse/ParseOpenMP.cpp
+++ b/clang/lib/Parse/ParseOpenMP.cpp
@@ -19,6 +19,7 @@
 #include "clang/Parse/ParseDiagnostic.h"
 #include "clang/Parse/Parser.h"
 #include "clang/Parse/RAIIObjectsForParser.h"
+#include "clang/Sema/EnterExpressionEvaluationContext.h"
 #include "clang/Sema/Scope.h"
 #include "llvm/ADT/PointerIntPair.h"
 #include "llvm/ADT/StringSwitch.h"
diff --git a/clang/lib/Parse/ParsePragma.cpp b/clang/lib/Parse/ParsePragma.cpp
--- a/clang/lib/Parse/ParsePragma.cpp
+++ b/clang/lib/Parse/ParsePragma.cpp
@@ -19,6 +19,7 @@
 #include "clang/Parse/ParseDiagnostic.h"
 #include "clang/Parse/Parser.h"
 #include "clang/Parse/RAIIObjectsForParser.h"
+#include "clang/Sema/EnterExpressionEvaluationContext.h"
 #include "clang/Sema/Scope.h"
 #include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/StringSwitch.h"
diff --git a/clang/lib/Parse/ParseStmt.cpp b/clang/lib/Parse/ParseStmt.cpp
--- a/clang/lib/Parse/ParseStmt.cpp
+++ b/clang/lib/Parse/ParseStmt.cpp
@@ -19,6 +19,7 @@
 #include "clang/Parse/Parser.h"
 #include "clang/Parse/RAIIObjectsForParser.h"
 #include "clang/Sema/DeclSpec.h"
+#include "clang/Sema/EnterExpressionEvaluationContext.h"
 #include "clang/Sema/Scope.h"
 #include "clang/Sema/TypoCorrection.h"
 #include "llvm/ADT/STLExtras.h"
diff --git a/clang/lib/Parse/ParseTemplate.cpp b/clang/lib/Parse/ParseTemplate.cpp
--- a/clang/lib/Parse/ParseTemplate.cpp
+++ b/clang/lib/Parse/ParseTemplate.cpp
@@ -17,6 +17,7 @@
 #include "clang/Parse/Parser.h"
 #include "clang/Parse/RAIIObjectsForParser.h"
 #include "clang/Sema/DeclSpec.h"
+#include "clang/Sema/EnterExpressionEvaluationContext.h"
 #include "clang/Sema/ParsedTemplate.h"
 #include "clang/Sema/Scope.h"
 #include "clang/Sema/SemaDiagnostic.h"
diff --git a/clang/lib/Sema/Sema.cpp b/clang/lib/Sema/Sema.cpp
--- a/clang/lib/Sema/Sema.cpp
+++ b/clang/lib/Sema/Sema.cpp
@@ -33,6 +33,7 @@
 #include "clang/Lex/Preprocessor.h"
 #include "clang/Sema/CXXFieldCollector.h"
 #include "clang/Sema/DelayedDiagnostic.h"
+#include "clang/Sema/EnterExpressionEvaluationContext.h"
 #include "clang/Sema/ExternalSemaSource.h"
 #include "clang/Sema/Initialization.h"
 #include "clang/Sema/MultiplexExternalSemaSource.h"
diff --git a/clang/lib/Sema/SemaConcept.cpp b/clang/lib/Sema/SemaConcept.cpp
--- a/clang/lib/Sema/SemaConcept.cpp
+++ b/clang/lib/Sema/SemaConcept.cpp
@@ -10,19 +10,20 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "TreeTransform.h"
 #include "clang/Sema/SemaConcept.h"
-#include "clang/Sema/Sema.h"
-#include "clang/Sema/SemaInternal.h"
-#include "clang/Sema/SemaDiagnostic.h"
-#include "clang/Sema/TemplateDeduction.h"
-#include "clang/Sema/Template.h"
-#include "clang/Sema/Overload.h"
-#include "clang/Sema/Initialization.h"
+#include "TreeTransform.h"
 #include "clang/AST/ASTLambda.h"
 #include "clang/AST/ExprConcepts.h"
 #include "clang/AST/RecursiveASTVisitor.h"
 #include "clang/Basic/OperatorPrecedence.h"
+#include "clang/Sema/EnterExpressionEvaluationContext.h"
+#include "clang/Sema/Initialization.h"
+#include "clang/Sema/Overload.h"
+#include "clang/Sema/Sema.h"
+#include "clang/Sema/SemaDiagnostic.h"
+#include "clang/Sema/SemaInternal.h"
+#include "clang/Sema/Template.h"
+#include "clang/Sema/TemplateDeduction.h"
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/PointerUnion.h"
 #include "llvm/ADT/StringExtras.h"
diff --git a/clang/lib/Sema/SemaDeclCXX.cpp b/clang/lib/Sema/SemaDeclCXX.cpp
--- a/clang/lib/Sema/SemaDeclCXX.cpp
+++ b/clang/lib/Sema/SemaDeclCXX.cpp
@@ -34,6 +34,7 @@
 #include "clang/Lex/Preprocessor.h"
 #include "clang/Sema/CXXFieldCollector.h"
 #include "clang/Sema/DeclSpec.h"
+#include "clang/Sema/EnterExpressionEvaluationContext.h"
 #include "clang/Sema/Initialization.h"
 #include "clang/Sema/Lookup.h"
 #include "clang/Sema/ParsedTemplate.h"
@@ -41,9 +42,9 @@
 #include "clang/Sema/ScopeInfo.h"
 #include "clang/Sema/SemaInternal.h"
 #include "clang/Sema/Template.h"
+#include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/ScopeExit.h"
 #include "llvm/ADT/SmallString.h"
-#include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/StringExtras.h"
 #include <map>
 #include <optional>
diff --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp
--- a/clang/lib/Sema/SemaExpr.cpp
+++ b/clang/lib/Sema/SemaExpr.cpp
@@ -41,6 +41,7 @@
 #include "clang/Sema/DeclSpec.h"
 #include "clang/Sema/DelayedDiagnostic.h"
 #include "clang/Sema/Designator.h"
+#include "clang/Sema/EnterExpressionEvaluationContext.h"
 #include "clang/Sema/Initialization.h"
 #include "clang/Sema/Lookup.h"
 #include "clang/Sema/Overload.h"
diff --git a/clang/lib/Sema/SemaExprCXX.cpp b/clang/lib/Sema/SemaExprCXX.cpp
--- a/clang/lib/Sema/SemaExprCXX.cpp
+++ b/clang/lib/Sema/SemaExprCXX.cpp
@@ -31,6 +31,7 @@
 #include "clang/Basic/TypeTraits.h"
 #include "clang/Lex/Preprocessor.h"
 #include "clang/Sema/DeclSpec.h"
+#include "clang/Sema/EnterExpressionEvaluationContext.h"
 #include "clang/Sema/Initialization.h"
 #include "clang/Sema/Lookup.h"
 #include "clang/Sema/ParsedTemplate.h"
diff --git a/clang/lib/Sema/SemaInit.cpp b/clang/lib/Sema/SemaInit.cpp
--- a/clang/lib/Sema/SemaInit.cpp
+++ b/clang/lib/Sema/SemaInit.cpp
@@ -20,6 +20,7 @@
 #include "clang/Basic/SourceManager.h"
 #include "clang/Basic/TargetInfo.h"
 #include "clang/Sema/Designator.h"
+#include "clang/Sema/EnterExpressionEvaluationContext.h"
 #include "clang/Sema/Initialization.h"
 #include "clang/Sema/Lookup.h"
 #include "clang/Sema/SemaInternal.h"
diff --git a/clang/lib/Sema/SemaOpenMP.cpp b/clang/lib/Sema/SemaOpenMP.cpp
--- a/clang/lib/Sema/SemaOpenMP.cpp
+++ b/clang/lib/Sema/SemaOpenMP.cpp
@@ -27,6 +27,7 @@
 #include "clang/Basic/OpenMPKinds.h"
 #include "clang/Basic/PartialDiagnostic.h"
 #include "clang/Basic/TargetInfo.h"
+#include "clang/Sema/EnterExpressionEvaluationContext.h"
 #include "clang/Sema/Initialization.h"
 #include "clang/Sema/Lookup.h"
 #include "clang/Sema/Scope.h"
diff --git a/clang/lib/Sema/SemaOverload.cpp b/clang/lib/Sema/SemaOverload.cpp
--- a/clang/lib/Sema/SemaOverload.cpp
+++ b/clang/lib/Sema/SemaOverload.cpp
@@ -26,6 +26,7 @@
 #include "clang/Basic/PartialDiagnostic.h"
 #include "clang/Basic/SourceManager.h"
 #include "clang/Basic/TargetInfo.h"
+#include "clang/Sema/EnterExpressionEvaluationContext.h"
 #include "clang/Sema/Initialization.h"
 #include "clang/Sema/Lookup.h"
 #include "clang/Sema/Overload.h"
diff --git a/clang/lib/Sema/SemaTemplate.cpp b/clang/lib/Sema/SemaTemplate.cpp
--- a/clang/lib/Sema/SemaTemplate.cpp
+++ b/clang/lib/Sema/SemaTemplate.cpp
@@ -26,6 +26,7 @@
 #include "clang/Basic/Stack.h"
 #include "clang/Basic/TargetInfo.h"
 #include "clang/Sema/DeclSpec.h"
+#include "clang/Sema/EnterExpressionEvaluationContext.h"
 #include "clang/Sema/Initialization.h"
 #include "clang/Sema/Lookup.h"
 #include "clang/Sema/Overload.h"
diff --git a/clang/lib/Sema/SemaTemplateDeduction.cpp b/clang/lib/Sema/SemaTemplateDeduction.cpp
--- a/clang/lib/Sema/SemaTemplateDeduction.cpp
+++ b/clang/lib/Sema/SemaTemplateDeduction.cpp
@@ -10,7 +10,6 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "clang/Sema/TemplateDeduction.h"
 #include "TreeTransform.h"
 #include "TypeLocBuilder.h"
 #include "clang/AST/ASTContext.h"
@@ -37,9 +36,11 @@
 #include "clang/Basic/PartialDiagnostic.h"
 #include "clang/Basic/SourceLocation.h"
 #include "clang/Basic/Specifiers.h"
+#include "clang/Sema/EnterExpressionEvaluationContext.h"
 #include "clang/Sema/Ownership.h"
 #include "clang/Sema/Sema.h"
 #include "clang/Sema/Template.h"
+#include "clang/Sema/TemplateDeduction.h"
 #include "llvm/ADT/APInt.h"
 #include "llvm/ADT/APSInt.h"
 #include "llvm/ADT/ArrayRef.h"
diff --git a/clang/lib/Sema/SemaTemplateInstantiate.cpp b/clang/lib/Sema/SemaTemplateInstantiate.cpp
--- a/clang/lib/Sema/SemaTemplateInstantiate.cpp
+++ b/clang/lib/Sema/SemaTemplateInstantiate.cpp
@@ -26,6 +26,7 @@
 #include "clang/Basic/Stack.h"
 #include "clang/Basic/TargetInfo.h"
 #include "clang/Sema/DeclSpec.h"
+#include "clang/Sema/EnterExpressionEvaluationContext.h"
 #include "clang/Sema/Initialization.h"
 #include "clang/Sema/Lookup.h"
 #include "clang/Sema/Sema.h"
diff --git a/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp b/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
--- a/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
+++ b/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
@@ -22,6 +22,7 @@
 #include "clang/AST/TypeLoc.h"
 #include "clang/Basic/SourceManager.h"
 #include "clang/Basic/TargetInfo.h"
+#include "clang/Sema/EnterExpressionEvaluationContext.h"
 #include "clang/Sema/Initialization.h"
 #include "clang/Sema/Lookup.h"
 #include "clang/Sema/ScopeInfo.h"
diff --git a/clang/lib/Sema/TreeTransform.h b/clang/lib/Sema/TreeTransform.h
--- a/clang/lib/Sema/TreeTransform.h
+++ b/clang/lib/Sema/TreeTransform.h
@@ -19,8 +19,8 @@
 #include "clang/AST/DeclObjC.h"
 #include "clang/AST/DeclTemplate.h"
 #include "clang/AST/Expr.h"
-#include "clang/AST/ExprConcepts.h"
 #include "clang/AST/ExprCXX.h"
+#include "clang/AST/ExprConcepts.h"
 #include "clang/AST/ExprObjC.h"
 #include "clang/AST/ExprOpenMP.h"
 #include "clang/AST/OpenMPClause.h"
@@ -31,6 +31,7 @@
 #include "clang/Basic/DiagnosticParse.h"
 #include "clang/Basic/OpenMPKinds.h"
 #include "clang/Sema/Designator.h"
+#include "clang/Sema/EnterExpressionEvaluationContext.h"
 #include "clang/Sema/Lookup.h"
 #include "clang/Sema/Ownership.h"
 #include "clang/Sema/ParsedTemplate.h"