[NFC] Drop typeCheckExternalDefinitions

Author: CodaFi

include/swift/Subsystems.h

@@ -232,9 +232,6 @@ namespace swift {
   /// of declarations in the module.
   void checkInconsistentImplementationOnlyImports(ModuleDecl *M);
 
-  /// Incrementally type-check only added external definitions.
-  void typeCheckExternalDefinitions(SourceFile &SF);
-
   /// Recursively validate the specified type.
   ///
   /// This is used when dealing with partial source files (e.g. SIL parsing,

lib/Sema/TypeChecker.cpp

@@ -334,12 +334,6 @@ static void typeCheckFunctionsAndExternalDecls(SourceFile &SF, TypeChecker &TC)
   TC.definedFunctions.clear();
 }
 
-void swift::typeCheckExternalDefinitions(SourceFile &SF) {
-  assert(SF.ASTStage == SourceFile::TypeChecked);
-  auto &Ctx = SF.getASTContext();
-  typeCheckFunctionsAndExternalDecls(SF, createTypeChecker(Ctx));
-}
-
 void swift::performTypeChecking(SourceFile &SF, TopLevelContext &TLC,
                                 OptionSet<TypeCheckingFlags> Options,
                                 unsigned StartElem,