Index: clang-tidy/misc/BoolPointerImplicitConversionCheck.cpp
===================================================================
--- clang-tidy/misc/BoolPointerImplicitConversionCheck.cpp
+++ clang-tidy/misc/BoolPointerImplicitConversionCheck.cpp
@@ -15,14 +15,6 @@
 namespace tidy {
 namespace misc {
 
-namespace {
-
-AST_MATCHER(CastExpr, isPointerToBoolean) {
-  return Node.getCastKind() == CK_PointerToBoolean;
-}
-
-} // namespace
-
 void BoolPointerImplicitConversionCheck::registerMatchers(MatchFinder *Finder) {
   // Look for ifs that have an implicit bool* to bool conversion in the
   // condition. Filter negations.
@@ -32,7 +24,7 @@
                        hasSourceExpression(expr(
                            hasType(pointerType(pointee(booleanType()))),
                            ignoringParenImpCasts(declRefExpr().bind("expr")))),
-                       isPointerToBoolean())))),
+                       hasCastKind(CK_PointerToBoolean))))),
              unless(isInTemplateInstantiation())).bind("if"),
       this);
 }
Index: clang-tidy/modernize/UseNullptrCheck.cpp
===================================================================
--- clang-tidy/modernize/UseNullptrCheck.cpp
+++ clang-tidy/modernize/UseNullptrCheck.cpp
@@ -24,20 +24,6 @@
 
 const char CastSequence[] = "sequence";
 
-/// \brief Matches cast expressions that have a cast kind of CK_NullToPointer
-/// or CK_NullToMemberPointer.
-///
-/// Given
-/// \code
-///   int *p = 0;
-/// \endcode
-/// implicitCastExpr(isNullToPointer()) matches the implicit cast clang adds
-/// around \c 0.
-AST_MATCHER(CastExpr, isNullToPointer) {
-  return Node.getCastKind() == CK_NullToPointer ||
-         Node.getCastKind() == CK_NullToMemberPointer;
-}
-
 AST_MATCHER(Type, sugaredNullptrType) {
   const Type *DesugaredType = Node.getUnqualifiedDesugaredType();
   if (const BuiltinType *BT = dyn_cast<BuiltinType>(DesugaredType))
@@ -52,7 +38,8 @@
 /// can be replaced instead of just the inner-most implicit cast.
 StatementMatcher makeCastSequenceMatcher() {
   StatementMatcher ImplicitCastToNull = implicitCastExpr(
-      isNullToPointer(),
+      anyOf(hasCastKind(CK_NullToPointer),
+            hasCastKind(CK_NullToMemberPointer)),
       unless(hasSourceExpression(hasType(sugaredNullptrType()))));
 
   return castExpr(anyOf(ImplicitCastToNull,
Index: clang-tidy/performance/FasterStringFindCheck.cpp
===================================================================
--- clang-tidy/performance/FasterStringFindCheck.cpp
+++ clang-tidy/performance/FasterStringFindCheck.cpp
@@ -38,8 +38,6 @@
   return Result;
 }
 
-AST_MATCHER(StringLiteral, lengthIsOne) { return Node.getLength() == 1; }
-
 AST_MATCHER_FUNCTION(ast_matchers::internal::Matcher<Expr>,
                      hasSubstitutedType) {
   return hasType(qualType(anyOf(substTemplateTypeParmType(),
@@ -65,7 +63,7 @@
     return;
 
   const auto SingleChar =
-      expr(ignoringParenCasts(stringLiteral(lengthIsOne()).bind("literal")));
+      expr(ignoringParenCasts(stringLiteral(hasSize(1)).bind("literal")));
 
   const auto StringFindFunctions =
       anyOf(hasName("find"), hasName("rfind"), hasName("find_first_of"),
Index: clang-tidy/readability/ImplicitBoolCastCheck.cpp
===================================================================
--- clang-tidy/readability/ImplicitBoolCastCheck.cpp
+++ clang-tidy/readability/ImplicitBoolCastCheck.cpp
@@ -20,10 +20,6 @@
 
 namespace {
 
-AST_MATCHER_P(CastExpr, hasCastKind, CastKind, Kind) {
-  return Node.getCastKind() == Kind;
-}
-
 AST_MATCHER(Stmt, isMacroExpansion) {
   SourceManager &SM = Finder->getASTContext().getSourceManager();
   SourceLocation Loc = Node.getLocStart();
Index: clang-tidy/readability/RedundantStringInitCheck.cpp
===================================================================
--- clang-tidy/readability/RedundantStringInitCheck.cpp
+++ clang-tidy/readability/RedundantStringInitCheck.cpp
@@ -8,25 +8,16 @@
 //===----------------------------------------------------------------------===//
 
 #include "RedundantStringInitCheck.h"
+#include "../utils/Matchers.h"
 #include "clang/ASTMatchers/ASTMatchers.h"
 
 using namespace clang::ast_matchers;
+using namespace clang::tidy::matchers;
 
 namespace clang {
 namespace tidy {
 namespace readability {
 
-namespace {
-
-AST_MATCHER(StringLiteral, lengthIsZero) { return Node.getLength() == 0; }
-
-AST_MATCHER_P(Expr, ignoringImplicit,
-              ast_matchers::internal::Matcher<Expr>, InnerMatcher) {
-  return InnerMatcher.matches(*Node.IgnoreImplicit(), Finder, Builder);
-}
-
-} // namespace
-
 void RedundantStringInitCheck::registerMatchers(MatchFinder *Finder) {
   if (!getLangOpts().CPlusPlus)
     return;
@@ -45,7 +36,7 @@
   const auto EmptyStringCtorExpr =
       cxxConstructExpr(StringConstructorExpr,
           hasArgument(0, ignoringParenImpCasts(
-                             stringLiteral(lengthIsZero()))));
+                             stringLiteral(hasSize(0)))));
 
   const auto EmptyStringCtorExprWithTemporaries =
       expr(ignoringImplicit(
Index: clang-tidy/utils/Matchers.h
===================================================================
--- clang-tidy/utils/Matchers.h
+++ clang-tidy/utils/Matchers.h
@@ -17,6 +17,11 @@
 namespace tidy {
 namespace matchers {
 
+AST_MATCHER_P(Expr, ignoringImplicit,
+              ast_matchers::internal::Matcher<Expr>, InnerMatcher) {
+  return InnerMatcher.matches(*Node.IgnoreImplicit(), Finder, Builder);
+}
+
 AST_MATCHER(BinaryOperator, isRelationalOperator) {
   return Node.isRelationalOp();
 }