1 files changed, 26 insertions, 17 deletions

diff --git a/clang/lib/AST/Decl.cpp b/clang/lib/AST/Decl.cpp
index 6cfd4c2a2a2..e760fff2ff6 100644
--- a/clang/lib/AST/Decl.cpp
+++ b/clang/lib/AST/Decl.cpp
@@ -1839,21 +1839,25 @@ void DeclaratorDecl::setQualifierInfo(NestedNameSpecifierLoc QualifierLoc) {
     }
     // Set qualifier info.
     getExtInfo()->QualifierLoc = QualifierLoc;
-  } else {
+  } else if (hasExtInfo()) {
     // Here Qualifier == 0, i.e., we are removing the qualifier (if any).
-    if (hasExtInfo()) {
-      if (getExtInfo()->NumTemplParamLists == 0) {
-        // Save type source info pointer.
-        TypeSourceInfo *savedTInfo = getExtInfo()->TInfo;
-        // Deallocate the extended decl info.
-        getASTContext().Deallocate(getExtInfo());
-        // Restore savedTInfo into (non-extended) decl info.
-        DeclInfo = savedTInfo;
-      }
-      else
-        getExtInfo()->QualifierLoc = QualifierLoc;
-    }
+    getExtInfo()->QualifierLoc = QualifierLoc;
+  }
+}
+
+void DeclaratorDecl::setTrailingRequiresClause(Expr *TrailingRequiresClause) {
+  assert(TrailingRequiresClause);
+  // Make sure the extended decl info is allocated.
+  if (!hasExtInfo()) {
+    // Save (non-extended) type source info pointer.
+    auto *savedTInfo = DeclInfo.get<TypeSourceInfo*>();
+    // Allocate external info struct.
+    DeclInfo = new (getASTContext()) ExtInfo;
+    // Restore savedTInfo into (extended) decl info.
+    getExtInfo()->TInfo = savedTInfo;
   }
+  // Set requires clause info.
+  getExtInfo()->TrailingRequiresClause = TrailingRequiresClause;
 }
 
 void DeclaratorDecl::setTemplateParameterListsInfo(
@@ -2777,7 +2781,8 @@ FunctionDecl::FunctionDecl(Kind DK, ASTContext &C, DeclContext *DC,
                            const DeclarationNameInfo &NameInfo, QualType T,
                            TypeSourceInfo *TInfo, StorageClass S,
                            bool isInlineSpecified,
-                           ConstexprSpecKind ConstexprKind)
+                           ConstexprSpecKind ConstexprKind,
+                           Expr *TrailingRequiresClause)
     : DeclaratorDecl(DK, DC, NameInfo.getLoc(), NameInfo.getName(), T, TInfo,
                      StartLoc),
       DeclContext(DK), redeclarable_base(C), Body(), ODRHash(0),
@@ -2807,6 +2812,8 @@ FunctionDecl::FunctionDecl(Kind DK, ASTContext &C, DeclContext *DC,
   FunctionDeclBits.IsMultiVersion = false;
   FunctionDeclBits.IsCopyDeductionCandidate = false;
   FunctionDeclBits.HasODRHash = false;
+  if (TrailingRequiresClause)
+    setTrailingRequiresClause(TrailingRequiresClause);
 }
 
 void FunctionDecl::getNameForDiagnostic(
@@ -4683,10 +4690,12 @@ FunctionDecl *FunctionDecl::Create(ASTContext &C, DeclContext *DC,
                                    QualType T, TypeSourceInfo *TInfo,
                                    StorageClass SC, bool isInlineSpecified,
                                    bool hasWrittenPrototype,
-                                   ConstexprSpecKind ConstexprKind) {
+                                   ConstexprSpecKind ConstexprKind,
+                                   Expr *TrailingRequiresClause) {
   FunctionDecl *New =
       new (C, DC) FunctionDecl(Function, C, DC, StartLoc, NameInfo, T, TInfo,
-                               SC, isInlineSpecified, ConstexprKind);
+                               SC, isInlineSpecified, ConstexprKind,
+                               TrailingRequiresClause);
   New->setHasWrittenPrototype(hasWrittenPrototype);
   return New;
 }
@@ -4694,7 +4703,7 @@ FunctionDecl *FunctionDecl::Create(ASTContext &C, DeclContext *DC,
 FunctionDecl *FunctionDecl::CreateDeserialized(ASTContext &C, unsigned ID) {
   return new (C, ID) FunctionDecl(Function, C, nullptr, SourceLocation(),
                                   DeclarationNameInfo(), QualType(), nullptr,
-                                  SC_None, false, CSK_unspecified);
+                                  SC_None, false, CSK_unspecified, nullptr);
 }
 
 BlockDecl *BlockDecl::Create(ASTContext &C, DeclContext *DC, SourceLocation L) {