diff --git a/clang-tools-extra/clang-tidy/altera/StructPackAlignCheck.cpp b/clang-tools-extra/clang-tidy/altera/StructPackAlignCheck.cpp
--- a/clang-tools-extra/clang-tidy/altera/StructPackAlignCheck.cpp
+++ b/clang-tools-extra/clang-tidy/altera/StructPackAlignCheck.cpp
@@ -17,10 +17,11 @@
 namespace clang::tidy::altera {
 
 void StructPackAlignCheck::registerMatchers(MatchFinder *Finder) {
-  Finder->addMatcher(recordDecl(isStruct(), isDefinition(),
-                                unless(isExpansionInSystemHeader()))
-                         .bind("struct"),
-                     this);
+  Finder->addMatcher(
+      recordDecl(isStruct(), isDefinition(),
+                 unless(anyOf(isExpansionInSystemHeader(), isImplicit())))
+          .bind("struct"),
+      this);
 }
 
 CharUnits
diff --git a/clang-tools-extra/clang-tidy/cert/DontModifyStdNamespaceCheck.cpp b/clang-tools-extra/clang-tidy/cert/DontModifyStdNamespaceCheck.cpp
--- a/clang-tools-extra/clang-tidy/cert/DontModifyStdNamespaceCheck.cpp
+++ b/clang-tools-extra/clang-tidy/cert/DontModifyStdNamespaceCheck.cpp
@@ -40,10 +40,10 @@
 namespace clang::tidy::cert {
 
 void DontModifyStdNamespaceCheck::registerMatchers(MatchFinder *Finder) {
-  auto HasStdParent =
-      hasDeclContext(namespaceDecl(hasAnyName("std", "posix"),
-                                   unless(hasParent(namespaceDecl())))
-                         .bind("nmspc"));
+  auto HasStdParent = hasDeclContext(
+      namespaceDecl(hasAnyName("std", "posix"),
+                    unless(anyOf(isImplicit(), hasParent(namespaceDecl()))))
+          .bind("nmspc"));
   auto UserDefinedType = qualType(
       hasUnqualifiedDesugaredType(tagType(unless(hasDeclaration(tagDecl(
           hasAncestor(namespaceDecl(hasAnyName("std", "posix"),
diff --git a/clang-tools-extra/clang-tidy/utils/RenamerClangTidyCheck.cpp b/clang-tools-extra/clang-tidy/utils/RenamerClangTidyCheck.cpp
--- a/clang-tools-extra/clang-tidy/utils/RenamerClangTidyCheck.cpp
+++ b/clang-tools-extra/clang-tidy/utils/RenamerClangTidyCheck.cpp
@@ -111,7 +111,10 @@
 }
 
 void RenamerClangTidyCheck::registerMatchers(MatchFinder *Finder) {
-  Finder->addMatcher(namedDecl().bind("decl"), this);
+  Finder->addMatcher(
+      namedDecl(unless(anyOf(isImplicit(), hasDeclContext(isImplicit()))))
+          .bind("decl"),
+      this);
   Finder->addMatcher(usingDecl().bind("using"), this);
   Finder->addMatcher(declRefExpr().bind("declRef"), this);
   Finder->addMatcher(cxxConstructorDecl(unless(isImplicit())).bind("classRef"),
diff --git a/clang-tools-extra/test/clang-tidy/checkers/cert/dcl58-cpp.cpp b/clang-tools-extra/test/clang-tidy/checkers/cert/dcl58-cpp.cpp
--- a/clang-tools-extra/test/clang-tidy/checkers/cert/dcl58-cpp.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/cert/dcl58-cpp.cpp
@@ -1,4 +1,10 @@
 // RUN: %check_clang_tidy -std=c++17-or-later %s cert-dcl58-cpp %t -- -- -I %clang_tidy_headers
+// RUN: %check_clang_tidy -std=c++17-or-later %s cert-dcl58-cpp %t -- -- -I %clang_tidy_headers -target aarch64
+// RUN: %check_clang_tidy -std=c++17-or-later %s cert-dcl58-cpp %t -- -- -I %clang_tidy_headers -target arm
+
+// On arm and arch64 architectures, va_list is within the std namespace.
+// D136886 exposed an issue in the cert-dcl58-cpp checker where
+// implicit namespaces were not ignored.
 
 #include "system-header-simulation.h"
 
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -60,6 +60,7 @@
 - Fix crash when diagnosing incorrect usage of ``_Nullable`` involving alias
   templates. This fixes
   `Issue 60344 <https://github.com/llvm/llvm-project/issues/60344>`_.
+- Fix importing of va_list types and declarations.
 
 Improvements to Clang's diagnostics
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
diff --git a/clang/lib/Frontend/ASTMerge.cpp b/clang/lib/Frontend/ASTMerge.cpp
--- a/clang/lib/Frontend/ASTMerge.cpp
+++ b/clang/lib/Frontend/ASTMerge.cpp
@@ -59,12 +59,6 @@
 
     TranslationUnitDecl *TU = Unit->getASTContext().getTranslationUnitDecl();
     for (auto *D : TU->decls()) {
-      // Don't re-import __va_list_tag, __builtin_va_list.
-      if (const auto *ND = dyn_cast<NamedDecl>(D))
-        if (IdentifierInfo *II = ND->getIdentifier())
-          if (II->isStr("__va_list_tag") || II->isStr("__builtin_va_list"))
-            continue;
-
       llvm::Expected<Decl *> ToDOrError = Importer.Import(D);
 
       if (ToDOrError) {
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
@@ -276,6 +276,7 @@
   // This needs to happen after ExternalSemaSource::InitializeSema(this) or we
   // will not be able to merge any duplicate __va_list_tag decls correctly.
   VAListTagName = PP.getIdentifierInfo("__va_list_tag");
+  (void)PP.getIdentifierInfo("__va_list");
 
   if (!TUScope)
     return;
@@ -457,6 +458,26 @@
       PushOnScopeChains(Context.getBuiltinMSVaListDecl(), TUScope);
   }
 
+  if (auto *ND = dyn_cast_if_present<NamedDecl>(Context.getVaListTagDecl())) {
+    if (auto *DC = ND->getLexicalDeclContext(); DC->isStdNamespace()) {
+      auto *NS = cast<NamespaceDecl>(DC);
+      if (!StdNamespace)
+        StdNamespace = NS;
+      if (!Context.getTranslationUnitDecl()->containsDecl(NS))
+        PushOnScopeChains(NS, TUScope);
+      if (!DC->containsDecl(ND)) {
+        Scope S(TUScope, Scope::DeclScope, getDiagnostics());
+        PushDeclContext(&S, DC);
+        PushOnScopeChains(ND, &S);
+        PopDeclContext();
+      }
+    } else {
+      assert(DC == Context.getTranslationUnitDecl());
+      if (!DC->containsDecl(ND))
+        PushOnScopeChains(ND, TUScope);
+    }
+  }
+
   DeclarationName BuiltinVaList = &Context.Idents.get("__builtin_va_list");
   if (IdResolver.begin(BuiltinVaList) == IdResolver.end())
     PushOnScopeChains(Context.getBuiltinVaListDecl(), TUScope);
diff --git a/clang/test/AST/ast-dump-file-line-json.c b/clang/test/AST/ast-dump-file-line-json.c
--- a/clang/test/AST/ast-dump-file-line-json.c
+++ b/clang/test/AST/ast-dump-file-line-json.c
@@ -129,6 +129,82 @@
 // CHECK-NEXT:   },
 // CHECK-NEXT:   {
 // CHECK-NEXT:    "id": "0x{{.*}}",
+// CHECK-NEXT:    "kind": "RecordDecl",
+// CHECK-NEXT:    "loc": {},
+// CHECK-NEXT:    "range": {
+// CHECK-NEXT:     "begin": {},
+// CHECK-NEXT:     "end": {}
+// CHECK-NEXT:    },
+// CHECK-NEXT:    "isImplicit": true,
+// CHECK-NEXT:    "name": "__va_list_tag",
+// CHECK-NEXT:    "tagUsed": "struct",
+// CHECK-NEXT:    "completeDefinition": true,
+// CHECK-NEXT:    "inner": [
+// CHECK-NEXT:     {
+// CHECK-NEXT:      "id": "0x{{.*}}",
+// CHECK-NEXT:      "kind": "TypeVisibilityAttr",
+// CHECK-NEXT:      "range": {
+// CHECK-NEXT:       "begin": {},
+// CHECK-NEXT:       "end": {}
+// CHECK-NEXT:      },
+// CHECK-NEXT:      "implicit": true
+// CHECK-NEXT:     },
+// CHECK-NEXT:     {
+// CHECK-NEXT:      "id": "0x{{.*}}",
+// CHECK-NEXT:      "kind": "FieldDecl",
+// CHECK-NEXT:      "loc": {},
+// CHECK-NEXT:      "range": {
+// CHECK-NEXT:       "begin": {},
+// CHECK-NEXT:       "end": {}
+// CHECK-NEXT:      },
+// CHECK-NEXT:      "name": "gp_offset",
+// CHECK-NEXT:      "type": {
+// CHECK-NEXT:       "qualType": "unsigned int"
+// CHECK-NEXT:      }
+// CHECK-NEXT:     },
+// CHECK-NEXT:     {
+// CHECK-NEXT:      "id": "0x{{.*}}",
+// CHECK-NEXT:      "kind": "FieldDecl",
+// CHECK-NEXT:      "loc": {},
+// CHECK-NEXT:      "range": {
+// CHECK-NEXT:       "begin": {},
+// CHECK-NEXT:       "end": {}
+// CHECK-NEXT:      },
+// CHECK-NEXT:      "name": "fp_offset",
+// CHECK-NEXT:      "type": {
+// CHECK-NEXT:       "qualType": "unsigned int"
+// CHECK-NEXT:      }
+// CHECK-NEXT:     },
+// CHECK-NEXT:     {
+// CHECK-NEXT:      "id": "0x{{.*}}",
+// CHECK-NEXT:      "kind": "FieldDecl",
+// CHECK-NEXT:      "loc": {},
+// CHECK-NEXT:      "range": {
+// CHECK-NEXT:       "begin": {},
+// CHECK-NEXT:       "end": {}
+// CHECK-NEXT:      },
+// CHECK-NEXT:      "name": "overflow_arg_area",
+// CHECK-NEXT:      "type": {
+// CHECK-NEXT:       "qualType": "void *"
+// CHECK-NEXT:      }
+// CHECK-NEXT:     },
+// CHECK-NEXT:     {
+// CHECK-NEXT:      "id": "0x{{.*}}",
+// CHECK-NEXT:      "kind": "FieldDecl",
+// CHECK-NEXT:      "loc": {},
+// CHECK-NEXT:      "range": {
+// CHECK-NEXT:       "begin": {},
+// CHECK-NEXT:       "end": {}
+// CHECK-NEXT:      },
+// CHECK-NEXT:      "name": "reg_save_area",
+// CHECK-NEXT:      "type": {
+// CHECK-NEXT:       "qualType": "void *"
+// CHECK-NEXT:      }
+// CHECK-NEXT:     }
+// CHECK-NEXT:    ]
+// CHECK-NEXT:   },
+// CHECK-NEXT:   {
+// CHECK-NEXT:    "id": "0x{{.*}}",
 // CHECK-NEXT:    "kind": "TypedefDecl",
 // CHECK-NEXT:    "loc": {},
 // CHECK-NEXT:    "range": {
diff --git a/clang/test/AST/ast-dump-overloaded-operators.cpp b/clang/test/AST/ast-dump-overloaded-operators.cpp
--- a/clang/test/AST/ast-dump-overloaded-operators.cpp
+++ b/clang/test/AST/ast-dump-overloaded-operators.cpp
@@ -24,7 +24,7 @@
 // CHECK-NEXT: |-FunctionDecl {{.*}} <line:12:1, col:19> col:6{{( imported)?}} used operator, 'void (E, E)'
 // CHECK-NEXT: | |-ParmVarDecl {{.*}} <col:16> col:17{{( imported)?}} 'E'
 // CHECK-NEXT: | `-ParmVarDecl {{.*}} <col:18> col:19{{( imported)?}} 'E'
-// CHECK-NEXT: `-FunctionDecl {{.*}} <line:14:1, line:18:1> line:14:6{{( imported)?}} test 'void ()'
+// CHECK-NEXT:  -FunctionDecl {{.*}} <line:14:1, line:18:1> line:14:6{{( imported)?}} test 'void ()'
 // CHECK-NEXT:   `-CompoundStmt {{.*}} <col:13, line:18:1>
 // CHECK-NEXT:     |-DeclStmt {{.*}} <line:15:3, col:6>
 // CHECK-NEXT:     | `-VarDecl {{.*}} <col:3, col:5> col:5{{( imported)?}} used e 'E'
diff --git a/clang/test/AST/ast-dump-record-definition-data-json.cpp b/clang/test/AST/ast-dump-record-definition-data-json.cpp
--- a/clang/test/AST/ast-dump-record-definition-data-json.cpp
+++ b/clang/test/AST/ast-dump-record-definition-data-json.cpp
@@ -132,6 +132,128 @@
 // CHECK-NEXT:  "name": "__NSConstantString_tag"
 // CHECK-NEXT: }
 
+// CHECK-NOT: {{^}}Dumping
+// CHECK:  "kind": "CXXRecordDecl",
+// CHECK-NEXT:  "loc": {},
+// CHECK-NEXT:  "range": {
+// CHECK-NEXT:   "begin": {},
+// CHECK-NEXT:   "end": {}
+// CHECK-NEXT:  },
+// CHECK-NEXT:  "isImplicit": true,
+// CHECK-NEXT:  "name": "__va_list_tag",
+// CHECK-NEXT:  "tagUsed": "struct",
+// CHECK-NEXT:  "completeDefinition": true,
+// CHECK-NEXT:  "definitionData": {
+// CHECK-NEXT:   "canPassInRegisters": true,
+// CHECK-NEXT:   "copyAssign": {
+// CHECK-NEXT:    "hasConstParam": true,
+// CHECK-NEXT:    "implicitHasConstParam": true,
+// CHECK-NEXT:    "needsImplicit": true,
+// CHECK-NEXT:    "simple": true,
+// CHECK-NEXT:    "trivial": true
+// CHECK-NEXT:   },
+// CHECK-NEXT:   "copyCtor": {
+// CHECK-NEXT:    "hasConstParam": true,
+// CHECK-NEXT:    "implicitHasConstParam": true,
+// CHECK-NEXT:    "needsImplicit": true,
+// CHECK-NEXT:    "simple": true,
+// CHECK-NEXT:    "trivial": true
+// CHECK-NEXT:   },
+// CHECK-NEXT:   "defaultCtor": {
+// CHECK-NEXT:    "exists": true,
+// CHECK-NEXT:    "needsImplicit": true,
+// CHECK-NEXT:    "trivial": true
+// CHECK-NEXT:   },
+// CHECK-NEXT:   "dtor": {
+// CHECK-NEXT:    "irrelevant": true,
+// CHECK-NEXT:    "needsImplicit": true,
+// CHECK-NEXT:    "simple": true,
+// CHECK-NEXT:    "trivial": true
+// CHECK-NEXT:   },
+// CHECK-NEXT:   "isAggregate": true,
+// CHECK-NEXT:   "isLiteral": true,
+// CHECK-NEXT:   "isPOD": true,
+// CHECK-NEXT:   "isStandardLayout": true,
+// CHECK-NEXT:   "isTrivial": true,
+// CHECK-NEXT:   "isTriviallyCopyable": true,
+// CHECK-NEXT:   "moveAssign": {
+// CHECK-NEXT:    "exists": true,
+// CHECK-NEXT:    "needsImplicit": true,
+// CHECK-NEXT:    "simple": true,
+// CHECK-NEXT:    "trivial": true
+// CHECK-NEXT:   },
+// CHECK-NEXT:   "moveCtor": {
+// CHECK-NEXT:    "exists": true,
+// CHECK-NEXT:    "needsImplicit": true,
+// CHECK-NEXT:    "simple": true,
+// CHECK-NEXT:    "trivial": true
+// CHECK-NEXT:   }
+// CHECK-NEXT:  },
+// CHECK-NEXT:  "inner": [
+// CHECK-NEXT:   {
+// CHECK-NEXT:    "id": "0x{{.*}}",
+// CHECK-NEXT:    "kind": "TypeVisibilityAttr",
+// CHECK-NEXT:    "range": {
+// CHECK-NEXT:     "begin": {},
+// CHECK-NEXT:     "end": {}
+// CHECK-NEXT:    },
+// CHECK-NEXT:    "implicit": true
+// CHECK-NEXT:   },
+// CHECK-NEXT:   {
+// CHECK-NEXT:    "id": "0x{{.*}}",
+// CHECK-NEXT:    "kind": "FieldDecl",
+// CHECK-NEXT:    "loc": {},
+// CHECK-NEXT:    "range": {
+// CHECK-NEXT:     "begin": {},
+// CHECK-NEXT:     "end": {}
+// CHECK-NEXT:    },
+// CHECK-NEXT:    "name": "gp_offset",
+// CHECK-NEXT:    "type": {
+// CHECK-NEXT:     "qualType": "unsigned int"
+// CHECK-NEXT:    }
+// CHECK-NEXT:   },
+// CHECK-NEXT:   {
+// CHECK-NEXT:    "id": "0x{{.*}}",
+// CHECK-NEXT:    "kind": "FieldDecl",
+// CHECK-NEXT:    "loc": {},
+// CHECK-NEXT:    "range": {
+// CHECK-NEXT:     "begin": {},
+// CHECK-NEXT:     "end": {}
+// CHECK-NEXT:    },
+// CHECK-NEXT:    "name": "fp_offset",
+// CHECK-NEXT:    "type": {
+// CHECK-NEXT:     "qualType": "unsigned int"
+// CHECK-NEXT:    }
+// CHECK-NEXT:   },
+// CHECK-NEXT:   {
+// CHECK-NEXT:    "id": "0x{{.*}}",
+// CHECK-NEXT:    "kind": "FieldDecl",
+// CHECK-NEXT:    "loc": {},
+// CHECK-NEXT:    "range": {
+// CHECK-NEXT:     "begin": {},
+// CHECK-NEXT:     "end": {}
+// CHECK-NEXT:    },
+// CHECK-NEXT:    "name": "overflow_arg_area",
+// CHECK-NEXT:    "type": {
+// CHECK-NEXT:     "qualType": "void *"
+// CHECK-NEXT:    }
+// CHECK-NEXT:   },
+// CHECK-NEXT:   {
+// CHECK-NEXT:    "id": "0x{{.*}}",
+// CHECK-NEXT:    "kind": "FieldDecl",
+// CHECK-NEXT:    "loc": {},
+// CHECK-NEXT:    "range": {
+// CHECK-NEXT:     "begin": {},
+// CHECK-NEXT:     "end": {}
+// CHECK-NEXT:    },
+// CHECK-NEXT:    "name": "reg_save_area",
+// CHECK-NEXT:    "type": {
+// CHECK-NEXT:     "qualType": "void *"
+// CHECK-NEXT:    }
+// CHECK-NEXT:   }
+// CHECK-NEXT:  ]
+// CHECK-NEXT: }
+
 // CHECK-NOT: {{^}}Dumping
 // CHECK:  "kind": "CXXRecordDecl",
 // CHECK-NEXT:  "name": "__va_list_tag"
diff --git a/clang/test/AST/ast-dump-records-json.cpp b/clang/test/AST/ast-dump-records-json.cpp
--- a/clang/test/AST/ast-dump-records-json.cpp
+++ b/clang/test/AST/ast-dump-records-json.cpp
@@ -92,6 +92,128 @@
 // CHECK-NEXT:  "name": "__NSConstantString_tag"
 // CHECK-NEXT: }
 
+// CHECK-NOT: {{^}}Dumping
+// CHECK:  "kind": "CXXRecordDecl",
+// CHECK-NEXT:  "loc": {},
+// CHECK-NEXT:  "range": {
+// CHECK-NEXT:   "begin": {},
+// CHECK-NEXT:   "end": {}
+// CHECK-NEXT:  },
+// CHECK-NEXT:  "isImplicit": true,
+// CHECK-NEXT:  "name": "__va_list_tag",
+// CHECK-NEXT:  "tagUsed": "struct",
+// CHECK-NEXT:  "completeDefinition": true,
+// CHECK-NEXT:  "definitionData": {
+// CHECK-NEXT:   "canPassInRegisters": true,
+// CHECK-NEXT:   "copyAssign": {
+// CHECK-NEXT:    "hasConstParam": true,
+// CHECK-NEXT:    "implicitHasConstParam": true,
+// CHECK-NEXT:    "needsImplicit": true,
+// CHECK-NEXT:    "simple": true,
+// CHECK-NEXT:    "trivial": true
+// CHECK-NEXT:   },
+// CHECK-NEXT:   "copyCtor": {
+// CHECK-NEXT:    "hasConstParam": true,
+// CHECK-NEXT:    "implicitHasConstParam": true,
+// CHECK-NEXT:    "needsImplicit": true,
+// CHECK-NEXT:    "simple": true,
+// CHECK-NEXT:    "trivial": true
+// CHECK-NEXT:   },
+// CHECK-NEXT:   "defaultCtor": {
+// CHECK-NEXT:    "exists": true,
+// CHECK-NEXT:    "needsImplicit": true,
+// CHECK-NEXT:    "trivial": true
+// CHECK-NEXT:   },
+// CHECK-NEXT:   "dtor": {
+// CHECK-NEXT:    "irrelevant": true,
+// CHECK-NEXT:    "needsImplicit": true,
+// CHECK-NEXT:    "simple": true,
+// CHECK-NEXT:    "trivial": true
+// CHECK-NEXT:   },
+// CHECK-NEXT:   "isAggregate": true,
+// CHECK-NEXT:   "isLiteral": true,
+// CHECK-NEXT:   "isPOD": true,
+// CHECK-NEXT:   "isStandardLayout": true,
+// CHECK-NEXT:   "isTrivial": true,
+// CHECK-NEXT:   "isTriviallyCopyable": true,
+// CHECK-NEXT:   "moveAssign": {
+// CHECK-NEXT:    "exists": true,
+// CHECK-NEXT:    "needsImplicit": true,
+// CHECK-NEXT:    "simple": true,
+// CHECK-NEXT:    "trivial": true
+// CHECK-NEXT:   },
+// CHECK-NEXT:   "moveCtor": {
+// CHECK-NEXT:    "exists": true,
+// CHECK-NEXT:    "needsImplicit": true,
+// CHECK-NEXT:    "simple": true,
+// CHECK-NEXT:    "trivial": true
+// CHECK-NEXT:   }
+// CHECK-NEXT:  },
+// CHECK-NEXT:  "inner": [
+// CHECK-NEXT:   {
+// CHECK-NEXT:    "id": "0x{{.*}}",
+// CHECK-NEXT:    "kind": "TypeVisibilityAttr",
+// CHECK-NEXT:    "range": {
+// CHECK-NEXT:     "begin": {},
+// CHECK-NEXT:     "end": {}
+// CHECK-NEXT:    },
+// CHECK-NEXT:    "implicit": true
+// CHECK-NEXT:   },
+// CHECK-NEXT:   {
+// CHECK-NEXT:    "id": "0x{{.*}}",
+// CHECK-NEXT:    "kind": "FieldDecl",
+// CHECK-NEXT:    "loc": {},
+// CHECK-NEXT:    "range": {
+// CHECK-NEXT:     "begin": {},
+// CHECK-NEXT:     "end": {}
+// CHECK-NEXT:    },
+// CHECK-NEXT:    "name": "gp_offset",
+// CHECK-NEXT:    "type": {
+// CHECK-NEXT:     "qualType": "unsigned int"
+// CHECK-NEXT:    }
+// CHECK-NEXT:   },
+// CHECK-NEXT:   {
+// CHECK-NEXT:    "id": "0x{{.*}}",
+// CHECK-NEXT:    "kind": "FieldDecl",
+// CHECK-NEXT:    "loc": {},
+// CHECK-NEXT:    "range": {
+// CHECK-NEXT:     "begin": {},
+// CHECK-NEXT:     "end": {}
+// CHECK-NEXT:    },
+// CHECK-NEXT:    "name": "fp_offset",
+// CHECK-NEXT:    "type": {
+// CHECK-NEXT:     "qualType": "unsigned int"
+// CHECK-NEXT:    }
+// CHECK-NEXT:   },
+// CHECK-NEXT:   {
+// CHECK-NEXT:    "id": "0x{{.*}}",
+// CHECK-NEXT:    "kind": "FieldDecl",
+// CHECK-NEXT:    "loc": {},
+// CHECK-NEXT:    "range": {
+// CHECK-NEXT:     "begin": {},
+// CHECK-NEXT:     "end": {}
+// CHECK-NEXT:    },
+// CHECK-NEXT:    "name": "overflow_arg_area",
+// CHECK-NEXT:    "type": {
+// CHECK-NEXT:     "qualType": "void *"
+// CHECK-NEXT:    }
+// CHECK-NEXT:   },
+// CHECK-NEXT:   {
+// CHECK-NEXT:    "id": "0x{{.*}}",
+// CHECK-NEXT:    "kind": "FieldDecl",
+// CHECK-NEXT:    "loc": {},
+// CHECK-NEXT:    "range": {
+// CHECK-NEXT:     "begin": {},
+// CHECK-NEXT:     "end": {}
+// CHECK-NEXT:    },
+// CHECK-NEXT:    "name": "reg_save_area",
+// CHECK-NEXT:    "type": {
+// CHECK-NEXT:     "qualType": "void *"
+// CHECK-NEXT:    }
+// CHECK-NEXT:   }
+// CHECK-NEXT:  ]
+// CHECK-NEXT: }
+
 // CHECK-NOT: {{^}}Dumping
 // CHECK:  "kind": "CXXRecordDecl",
 // CHECK-NEXT:  "name": "__va_list_tag"
diff --git a/clang/test/AST/ast-dump-records.cpp b/clang/test/AST/ast-dump-records.cpp
--- a/clang/test/AST/ast-dump-records.cpp
+++ b/clang/test/AST/ast-dump-records.cpp
@@ -308,7 +308,7 @@
 };
 
 struct CheckNoCleanup {
-// CHECK: `-CXXRecordDecl {{.*}} struct CheckNoCleanup definition
+// CHECK: {{.*}}-CXXRecordDecl {{.*}} struct CheckNoCleanup definition
   static constexpr char kConstant = '+';
 // CHECK: `-VarDecl {{.*}} kConstant 'const char' static inline constexpr cinit
 // CHECK-NEXT: |-value: Int 43
diff --git a/clang/test/AST/ast-dump-template-decls-json.cpp b/clang/test/AST/ast-dump-template-decls-json.cpp
--- a/clang/test/AST/ast-dump-template-decls-json.cpp
+++ b/clang/test/AST/ast-dump-template-decls-json.cpp
@@ -177,6 +177,128 @@
 // CHECK-NEXT:   },
 // CHECK-NEXT:   {
 // CHECK-NEXT:    "id": "0x{{.*}}",
+// CHECK-NEXT:    "kind": "CXXRecordDecl",
+// CHECK-NEXT:    "loc": {},
+// CHECK-NEXT:    "range": {
+// CHECK-NEXT:     "begin": {},
+// CHECK-NEXT:     "end": {}
+// CHECK-NEXT:    },
+// CHECK-NEXT:    "isImplicit": true,
+// CHECK-NEXT:    "name": "__va_list_tag",
+// CHECK-NEXT:    "tagUsed": "struct",
+// CHECK-NEXT:    "completeDefinition": true,
+// CHECK-NEXT:    "definitionData": {
+// CHECK-NEXT:     "canPassInRegisters": true,
+// CHECK-NEXT:     "copyAssign": {
+// CHECK-NEXT:      "hasConstParam": true,
+// CHECK-NEXT:      "implicitHasConstParam": true,
+// CHECK-NEXT:      "needsImplicit": true,
+// CHECK-NEXT:      "simple": true,
+// CHECK-NEXT:      "trivial": true
+// CHECK-NEXT:     },
+// CHECK-NEXT:     "copyCtor": {
+// CHECK-NEXT:      "hasConstParam": true,
+// CHECK-NEXT:      "implicitHasConstParam": true,
+// CHECK-NEXT:      "needsImplicit": true,
+// CHECK-NEXT:      "simple": true,
+// CHECK-NEXT:      "trivial": true
+// CHECK-NEXT:     },
+// CHECK-NEXT:     "defaultCtor": {
+// CHECK-NEXT:      "exists": true,
+// CHECK-NEXT:      "needsImplicit": true,
+// CHECK-NEXT:      "trivial": true
+// CHECK-NEXT:     },
+// CHECK-NEXT:     "dtor": {
+// CHECK-NEXT:      "irrelevant": true,
+// CHECK-NEXT:      "needsImplicit": true,
+// CHECK-NEXT:      "simple": true,
+// CHECK-NEXT:      "trivial": true
+// CHECK-NEXT:     },
+// CHECK-NEXT:     "isAggregate": true,
+// CHECK-NEXT:     "isLiteral": true,
+// CHECK-NEXT:     "isPOD": true,
+// CHECK-NEXT:     "isStandardLayout": true,
+// CHECK-NEXT:     "isTrivial": true,
+// CHECK-NEXT:     "isTriviallyCopyable": true,
+// CHECK-NEXT:     "moveAssign": {
+// CHECK-NEXT:      "exists": true,
+// CHECK-NEXT:      "needsImplicit": true,
+// CHECK-NEXT:      "simple": true,
+// CHECK-NEXT:      "trivial": true
+// CHECK-NEXT:     },
+// CHECK-NEXT:     "moveCtor": {
+// CHECK-NEXT:      "exists": true,
+// CHECK-NEXT:      "needsImplicit": true,
+// CHECK-NEXT:      "simple": true,
+// CHECK-NEXT:      "trivial": true
+// CHECK-NEXT:     }
+// CHECK-NEXT:    },
+// CHECK-NEXT:    "inner": [
+// CHECK-NEXT:     {
+// CHECK-NEXT:      "id": "0x{{.*}}",
+// CHECK-NEXT:      "kind": "TypeVisibilityAttr",
+// CHECK-NEXT:      "range": {
+// CHECK-NEXT:       "begin": {},
+// CHECK-NEXT:       "end": {}
+// CHECK-NEXT:      },
+// CHECK-NEXT:      "implicit": true
+// CHECK-NEXT:     },
+// CHECK-NEXT:     {
+// CHECK-NEXT:      "id": "0x{{.*}}",
+// CHECK-NEXT:      "kind": "FieldDecl",
+// CHECK-NEXT:      "loc": {},
+// CHECK-NEXT:      "range": {
+// CHECK-NEXT:       "begin": {},
+// CHECK-NEXT:       "end": {}
+// CHECK-NEXT:      },
+// CHECK-NEXT:      "name": "gp_offset",
+// CHECK-NEXT:      "type": {
+// CHECK-NEXT:       "qualType": "unsigned int"
+// CHECK-NEXT:      }
+// CHECK-NEXT:     },
+// CHECK-NEXT:     {
+// CHECK-NEXT:      "id": "0x{{.*}}",
+// CHECK-NEXT:      "kind": "FieldDecl",
+// CHECK-NEXT:      "loc": {},
+// CHECK-NEXT:      "range": {
+// CHECK-NEXT:       "begin": {},
+// CHECK-NEXT:       "end": {}
+// CHECK-NEXT:      },
+// CHECK-NEXT:      "name": "fp_offset",
+// CHECK-NEXT:      "type": {
+// CHECK-NEXT:       "qualType": "unsigned int"
+// CHECK-NEXT:      }
+// CHECK-NEXT:     },
+// CHECK-NEXT:     {
+// CHECK-NEXT:      "id": "0x{{.*}}",
+// CHECK-NEXT:      "kind": "FieldDecl",
+// CHECK-NEXT:      "loc": {},
+// CHECK-NEXT:      "range": {
+// CHECK-NEXT:       "begin": {},
+// CHECK-NEXT:       "end": {}
+// CHECK-NEXT:      },
+// CHECK-NEXT:      "name": "overflow_arg_area",
+// CHECK-NEXT:      "type": {
+// CHECK-NEXT:       "qualType": "void *"
+// CHECK-NEXT:      }
+// CHECK-NEXT:     },
+// CHECK-NEXT:     {
+// CHECK-NEXT:      "id": "0x{{.*}}",
+// CHECK-NEXT:      "kind": "FieldDecl",
+// CHECK-NEXT:      "loc": {},
+// CHECK-NEXT:      "range": {
+// CHECK-NEXT:       "begin": {},
+// CHECK-NEXT:       "end": {}
+// CHECK-NEXT:      },
+// CHECK-NEXT:      "name": "reg_save_area",
+// CHECK-NEXT:      "type": {
+// CHECK-NEXT:       "qualType": "void *"
+// CHECK-NEXT:      }
+// CHECK-NEXT:     }
+// CHECK-NEXT:    ]
+// CHECK-NEXT:   },
+// CHECK-NEXT:   {
+// CHECK-NEXT:    "id": "0x{{.*}}",
 // CHECK-NEXT:    "kind": "TypedefDecl",
 // CHECK-NEXT:    "loc": {},
 // CHECK-NEXT:    "range": {
diff --git a/clang/test/AST/ast-dump-traits.cpp b/clang/test/AST/ast-dump-traits.cpp
--- a/clang/test/AST/ast-dump-traits.cpp
+++ b/clang/test/AST/ast-dump-traits.cpp
@@ -52,7 +52,7 @@
 // CHECK-NEXT: | `-CompoundStmt {{.*}} <col:30, line:28:1>
 // CHECK-NEXT: |   `-CStyleCastExpr {{.*}} <line:27:3, col:28> 'void' <ToVoid>
 // CHECK-NEXT: |     `-ExpressionTraitExpr {{.*}} <col:10, col:28> 'bool' __is_lvalue_expr
-// CHECK-NEXT: `-FunctionDecl {{.*}} <line:30:1, line:35:1> line:30:6{{( imported)?}} test_unary_expr_or_type_trait 'void ()'
+// CHECK-NEXT:  -FunctionDecl {{.*}} <line:30:1, line:35:1> line:30:6{{( imported)?}} test_unary_expr_or_type_trait 'void ()'
 // CHECK-NEXT:   `-CompoundStmt {{.*}} <col:38, line:35:1>
 // CHECK-NEXT:     |-CStyleCastExpr {{.*}} <line:32:3, col:20> 'void' <ToVoid>
 // CHECK-NEXT:     | `-UnaryExprOrTypeTraitExpr {{.*}} <col:10, col:20> 'unsigned long' sizeof 'int'
diff --git a/clang/test/AST/fixed_point.c b/clang/test/AST/fixed_point.c
--- a/clang/test/AST/fixed_point.c
+++ b/clang/test/AST/fixed_point.c
@@ -402,5 +402,5 @@
 
 _Accum literallast = 1.0k;    // One
 
-//CHECK-NEXT: `-VarDecl {{.*}} literallast '_Accum' cinit
+//CHECK-NEXT:  -VarDecl {{.*}} literallast '_Accum' cinit
 //CHECK-NEXT:   `-FixedPointLiteral {{.*}} '_Accum' 1.0
diff --git a/clang/test/AST/float16.cpp b/clang/test/AST/float16.cpp
--- a/clang/test/AST/float16.cpp
+++ b/clang/test/AST/float16.cpp
@@ -29,7 +29,7 @@
   }
 }
 
-//CHECK:      |-NamespaceDecl
+//CHECK:      |-NamespaceDecl {{.*}} <{{.*}}:22:1,
 //CHECK-NEXT: | |-VarDecl {{.*}} f1n '_Float16'
 //CHECK-NEXT: | |-VarDecl {{.*}} f2n '_Float16' cinit
 //CHECK-NEXT: | | `-FloatingLiteral {{.*}} '_Float16' 3.300000e+01
diff --git a/clang/test/PCH/stmt-openmp_structured_block-bit.cpp b/clang/test/PCH/stmt-openmp_structured_block-bit.cpp
--- a/clang/test/PCH/stmt-openmp_structured_block-bit.cpp
+++ b/clang/test/PCH/stmt-openmp_structured_block-bit.cpp
@@ -13,7 +13,7 @@
 // expected-no-diagnostics
 
 // CHECK: TranslationUnitDecl 0x{{.*}} <<invalid sloc>> <invalid sloc>
-// CHECK: `-FunctionDecl 0x{{.*}} <{{.*}}stmt-openmp_structured_block-bit.cpp:8:1, line:11:1> line:8:6 {{(test|imported test)}} 'void ()'
+// CHECK:  -FunctionDecl 0x{{.*}} <{{.*}}stmt-openmp_structured_block-bit.cpp:8:1, line:11:1> line:8:6 {{(test|imported test)}} 'void ()'
 // CHECK-NEXT:   `-CompoundStmt 0x{{.*}} <col:13, line:11:1>
 // CHECK-NEXT:     `-OMPParallelDirective 0x{{.*}} <line:9:1, col:21>
 // CHECK-NEXT:       `-CapturedStmt 0x{{.*}} <line:10:3>
diff --git a/clang/unittests/AST/ASTImporterTest.cpp b/clang/unittests/AST/ASTImporterTest.cpp
--- a/clang/unittests/AST/ASTImporterTest.cpp
+++ b/clang/unittests/AST/ASTImporterTest.cpp
@@ -1248,8 +1248,8 @@
         }
         )";
   Decl *FromTU = getTuDecl(Code, Lang_CXX03);
-  auto FromNs =
-      FirstDeclMatcher<NamespaceDecl>().match(FromTU, namespaceDecl());
+  auto FromNs = FirstDeclMatcher<NamespaceDecl>().match(
+      FromTU, namespaceDecl(hasName("x")));
   auto ToNs = cast<NamespaceDecl>(Import(FromNs, Lang_CXX03));
   ASSERT_TRUE(ToNs);
   auto From =
@@ -7561,7 +7561,14 @@
       }
       )",
       Lang_CXX14);
-  auto *FromFD = FirstDeclMatcher<FieldDecl>().match(FromTU, fieldDecl());
+
+  auto *FromF = FirstDeclMatcher<FunctionDecl>().match(
+      FromTU, functionDecl(hasName("declToImport")));
+  CXXRecordDecl *FromLambda =
+      cast<LambdaExpr>((cast<CompoundStmt>(FromF->getBody())->body_back()))
+          ->getLambdaClass();
+
+  auto *FromFD = *FromLambda->field_begin();
   ASSERT_TRUE(FromFD);
   ASSERT_TRUE(FromFD->hasCapturedVLAType());
 
@@ -8137,6 +8144,24 @@
   EXPECT_FALSE(SharedStatePtr->isNewDecl(ToBar));
 }
 
+TEST_P(ASTImporterOptionSpecificTestBase, VaList) {
+  Decl *FromTU = getTuDecl(R"(typedef __builtin_va_list va_list;)", Lang_C99);
+
+  auto *FromVaList = FirstDeclMatcher<TypedefDecl>().match(
+      FromTU, typedefDecl(hasName("va_list")));
+  ASSERT_TRUE(FromVaList);
+
+  auto *ToVaList = Import(FromVaList, Lang_C99);
+  ASSERT_TRUE(ToVaList);
+
+  auto *ToBuiltinVaList = FirstDeclMatcher<TypedefDecl>().match(
+      ToAST->getASTContext().getTranslationUnitDecl(),
+      typedefDecl(hasName("__builtin_va_list")));
+
+  ASSERT_TRUE(ToAST->getASTContext().hasSameType(
+      ToVaList->getUnderlyingType(), ToBuiltinVaList->getUnderlyingType()));
+}
+
 INSTANTIATE_TEST_SUITE_P(ParameterizedTests, ASTImporterLookupTableTest,
                          DefaultTestValuesForRunOptions);