diff --git a/clang/include/clang/Parse/LoopHint.h b/clang/include/clang/Parse/LoopHint.h
--- a/clang/include/clang/Parse/LoopHint.h
+++ b/clang/include/clang/Parse/LoopHint.h
@@ -9,13 +9,13 @@
 #ifndef LLVM_CLANG_PARSE_LOOPHINT_H
 #define LLVM_CLANG_PARSE_LOOPHINT_H
 
-#include "clang/Basic/IdentifierTable.h"
 #include "clang/Basic/SourceLocation.h"
-#include "clang/Sema/Ownership.h"
-#include "clang/Sema/ParsedAttr.h"
 
 namespace clang {
 
+class Expr;
+struct IdentifierLoc;
+
 /// Loop optimization hint for loop and unroll pragmas.
 struct LoopHint {
   // Source range of the directive.
diff --git a/clang/include/clang/Parse/Parser.h b/clang/include/clang/Parse/Parser.h
--- a/clang/include/clang/Parse/Parser.h
+++ b/clang/include/clang/Parse/Parser.h
@@ -13,22 +13,13 @@
 #ifndef LLVM_CLANG_PARSE_PARSER_H
 #define LLVM_CLANG_PARSE_PARSER_H
 
-#include "clang/AST/Availability.h"
-#include "clang/Basic/BitmaskEnum.h"
-#include "clang/Basic/OpenMPKinds.h"
 #include "clang/Basic/OperatorPrecedence.h"
-#include "clang/Basic/Specifiers.h"
-#include "clang/Basic/TokenKinds.h"
 #include "clang/Lex/CodeCompletionHandler.h"
 #include "clang/Lex/Preprocessor.h"
-#include "clang/Sema/DeclSpec.h"
 #include "clang/Sema/Sema.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/Frontend/OpenMP/OMPContext.h"
-#include "llvm/Support/Compiler.h"
-#include "llvm/Support/PrettyStackTrace.h"
 #include "llvm/Support/SaveAndRestore.h"
-#include <memory>
 #include <optional>
 #include <stack>
 
diff --git a/clang/include/clang/Parse/RAIIObjectsForParser.h b/clang/include/clang/Parse/RAIIObjectsForParser.h
--- a/clang/include/clang/Parse/RAIIObjectsForParser.h
+++ b/clang/include/clang/Parse/RAIIObjectsForParser.h
@@ -15,12 +15,12 @@
 #define LLVM_CLANG_PARSE_RAIIOBJECTSFORPARSER_H
 
 #include "clang/Parse/ParseDiagnostic.h"
-#include "clang/Parse/Parser.h"
 #include "clang/Sema/DelayedDiagnostic.h"
-#include "clang/Sema/ParsedTemplate.h"
 #include "clang/Sema/Sema.h"
 
 namespace clang {
+  class ParsedAttributes;
+
   // TODO: move ParsingClassDefinition here.
   // TODO: move TentativeParsingAction here.