[ClangImporter] Simplify the importMethodType helper.

Once upon a time this was agnostic of the declaration being imported
(and possibly even still merged with importFunctionType) but that
hasn't been true for a while. If we're passing the ObjCMethodDecl
and ImportedName anyway, we don't need to separately pass the result
type, whether it's noreturn, and the Swift name as separate arguments.

No intended functionality change.

lib/ClangImporter/ImportDecl.cpp

@@ -3309,20 +3309,16 @@ namespace {
         kind = SpecialMethodKind::NSDictionarySubscriptGetter;
 
       // Import the type that this method will have.
-      DeclName name = importedName.getDeclName();
       Optional<ForeignErrorConvention> errorConvention;
       bodyParams.push_back(nullptr);
       auto type = Impl.importMethodType(dc,
                                         decl,
-                                        decl->getReturnType(),
                                         { decl->param_begin(),
                                           decl->param_size() },
                                         decl->isVariadic(),
-                                        decl->hasAttr<clang::NoReturnAttr>(),
                                         isInSystemModule(dc),
                                         &bodyParams.back(),
                                         importedName,
-                                        name,
                                         errorConvention,
                                         kind);
       if (!type)
@@ -3341,11 +3337,10 @@ namespace {
 
       auto result = FuncDecl::create(
           Impl.SwiftContext, /*StaticLoc=*/SourceLoc(),
-          StaticSpellingKind::None,
-          /*FuncLoc=*/SourceLoc(), name, /*NameLoc=*/SourceLoc(),
+          StaticSpellingKind::None, /*FuncLoc=*/SourceLoc(),
+          importedName.getDeclName(), /*NameLoc=*/SourceLoc(),
           /*Throws=*/importedName.getErrorInfo().hasValue(),
-          /*ThrowsLoc=*/SourceLoc(),
-          /*AccessorKeywordLoc=*/SourceLoc(),
+          /*ThrowsLoc=*/SourceLoc(), /*AccessorKeywordLoc=*/SourceLoc(),
           /*GenericParams=*/nullptr, bodyParams, TypeLoc(), dc, decl);
 
       result->setAccessibility(getOverridableAccessibility(dc));
@@ -5232,12 +5227,10 @@ ConstructorDecl *SwiftDeclConverter::importConstructor(
 
   // Import the type that this method will have.
   Optional<ForeignErrorConvention> errorConvention;
-  DeclName name = importedName.getDeclName();
   bodyParams.push_back(nullptr);
   auto type = Impl.importMethodType(
-      dc, objcMethod, objcMethod->getReturnType(), args, variadic,
-      objcMethod->hasAttr<clang::NoReturnAttr>(), isInSystemModule(dc),
-      &bodyParams.back(), importedName, name, errorConvention,
+      dc, objcMethod, args, variadic, isInSystemModule(dc),
+      &bodyParams.back(), importedName, errorConvention,
       SpecialMethodKind::Constructor);
   if (!type)
     return nullptr;
@@ -5265,7 +5258,7 @@ ConstructorDecl *SwiftDeclConverter::importConstructor(
                             ->getResult()
                             ->castTo<AnyFunctionType>()
                             ->getInput();
-  for (auto other : ownerNominal->lookupDirect(name)) {
+  for (auto other : ownerNominal->lookupDirect(importedName.getDeclName())) {
     auto ctor = dyn_cast<ConstructorDecl>(other);
     if (!ctor || ctor->isInvalid() ||
         ctor->getAttrs().isUnavailable(Impl.SwiftContext) ||
@@ -5342,8 +5335,8 @@ ConstructorDecl *SwiftDeclConverter::importConstructor(
 
   // Create the actual constructor.
   auto result = Impl.createDeclWithClangNode<ConstructorDecl>(
-      objcMethod, Accessibility::Public, name, /*NameLoc=*/SourceLoc(),
-      failability, /*FailabilityLoc=*/SourceLoc(),
+      objcMethod, Accessibility::Public, importedName.getDeclName(),
+      /*NameLoc=*/SourceLoc(), failability, /*FailabilityLoc=*/SourceLoc(),
       /*Throws=*/importedName.getErrorInfo().hasValue(),
       /*ThrowsLoc=*/SourceLoc(), selfVar, bodyParams.back(),
       /*GenericParams=*/nullptr, dc);

lib/ClangImporter/ImportType.cpp

@@ -1824,13 +1824,11 @@ getForeignErrorInfo(ForeignErrorConvention::Info errorInfo,
 Type ClangImporter::Implementation::importMethodType(
        const DeclContext *dc,
        const clang::ObjCMethodDecl *clangDecl,
-       clang::QualType resultType,
        ArrayRef<const clang::ParmVarDecl *> params,
-       bool isVariadic, bool isNoReturn,
+       bool isVariadic,
        bool isFromSystemModule,
        ParameterList **bodyParams,
        ImportedName importedName,
-       DeclName &methodName,
        Optional<ForeignErrorConvention> &foreignErrorInfo,
        SpecialMethodKind kind) {
 
@@ -1913,6 +1911,7 @@ Type ClangImporter::Implementation::importMethodType(
       }
     }
 
+    clang::QualType resultType = clangDecl->getReturnType();
     swiftResultTy = importType(resultType, resultKind,
                                allowNSUIntegerAsIntInResult,
                                /*isFullyBridgeable*/true,
@@ -1979,7 +1978,7 @@ Type ClangImporter::Implementation::importMethodType(
   unsigned numEffectiveParams = params.size();
   if (errorInfo) --numEffectiveParams;
 
-  auto argNames = methodName.getArgumentNames();
+  auto argNames = importedName.getDeclName().getArgumentNames();
   unsigned nameIndex = 0;
   for (size_t paramIndex = 0; paramIndex != params.size(); paramIndex++) {
     auto param = params[paramIndex];
@@ -2100,9 +2099,10 @@ Type ClangImporter::Implementation::importMethodType(
            errorInfo->ErrorParameterIndex == params.size() - 1);
 
       auto defaultArg = inferDefaultArgument(
-          param->getType(), optionalityOfParam, methodName.getBaseName(),
-          numEffectiveParams, name.empty() ? StringRef() : name.str(),
-          paramIndex == 0, isLastParameter, getNameImporter());
+          param->getType(), optionalityOfParam,
+          importedName.getDeclName().getBaseName(), numEffectiveParams,
+          name.empty() ? StringRef() : name.str(), paramIndex == 0,
+          isLastParameter, getNameImporter());
       if (defaultArg != DefaultArgumentKind::None)
         paramInfo->setDefaultArgumentKind(defaultArg);
     }
@@ -2135,7 +2135,7 @@ Type ClangImporter::Implementation::importMethodType(
   // Form the parameter list.
   *bodyParams = ParameterList::create(SwiftContext, swiftParams);
 
-  if (isNoReturn) {
+  if (clangDecl->hasAttr<clang::NoReturnAttr>()) {
     origSwiftResultTy = SwiftContext.getNeverType();
     swiftResultTy = SwiftContext.getNeverType();
   }

lib/ClangImporter/ImporterImpl.h

@@ -979,25 +979,24 @@ public:
                        StringRef argumentLabel, bool isFirstParameter,
                        bool isLastParameter, importer::NameImporter &);
 
-  /// \brief Import the type of an Objective-C method.
+  /// Import the type of an Objective-C method.
   ///
   /// This routine should be preferred when importing function types for
   /// which we have actual function parameters, e.g., when dealing with a
   /// function declaration, because it produces a function type whose input
   /// tuple has argument names.
   ///
-  /// \param clangDecl The underlying declaration, if any; should only be
-  ///   considered for any attributes it might carry.
-  /// \param resultType The result type of the function.
-  /// \param params The parameter types to the function.
+  /// \param dc The context the method is being imported into.
+  /// \param clangDecl The underlying declaration.
+  /// \param params The parameter types to the function. Note that this may not
+  ///        include all parameters defined on the ObjCMethodDecl.
   /// \param isVariadic Whether the function is variadic.
-  /// \param isNoReturn Whether the function is noreturn.
   /// \param isFromSystemModule Whether to apply special rules that only apply
   ///   to system APIs.
-  /// \param bodyParams The patterns visible inside the function body.
+  /// \param[out] bodyParams The patterns visible inside the function body.
   ///   whether the created arg/body patterns are different (selector-style).
-  /// \param importedName The name of the imported method.
-  /// \param errorConvention Information about the method's error conventions.
+  /// \param importedName How to import the name of the method.
+  /// \param[out] errorConvention Whether and how the method throws NSErrors.
   /// \param kind Controls whether we're building a type for a method that
   ///        needs special handling.
   ///
@@ -1005,13 +1004,11 @@ public:
   /// imported.
   Type importMethodType(const DeclContext *dc,
                         const clang::ObjCMethodDecl *clangDecl,
-                        clang::QualType resultType,
                         ArrayRef<const clang::ParmVarDecl *> params,
-                        bool isVariadic, bool isNoReturn,
+                        bool isVariadic,
                         bool isFromSystemModule,
                         ParameterList **bodyParams,
                         importer::ImportedName importedName,
-                        DeclName &name,
                         Optional<ForeignErrorConvention> &errorConvention,
                         SpecialMethodKind kind);