diff --git a/test/SourceKit/NameTranslation/basic.swift b/test/SourceKit/NameTranslation/basic.swift
index 3f44b3a551f..acc74f31318 100644
--- a/test/SourceKit/NameTranslation/basic.swift
+++ b/test/SourceKit/NameTranslation/basic.swift
@@ -23,6 +23,7 @@ func foo2 (_ a : FooClassDerived) {
 // RUN: %sourcekitd-test -req=translate -objc-selector FooClassDerived2 -pos=3:23 %s -- -F %S/../Inputs/libIDE-mock-sdk -I %t.tmp %mcp_opt %s | %FileCheck -check-prefix=CHECK11 %s
 // RUN: %sourcekitd-test -req=translate -objc-name fooProperty2 -pos=6:16 %s -- -F %S/../Inputs/libIDE-mock-sdk -I %t.tmp %mcp_opt %s | %FileCheck -check-prefix=CHECK2 %s
 // RUN: %sourcekitd-test -req=translate -objc-selector fooInstanceFunc1 -pos=7:16 %s -- -F %S/../Inputs/libIDE-mock-sdk -I %t.tmp %mcp_opt %s | %FileCheck -check-prefix=CHECK3 %s
+// RUN: %sourcekitd-test -req=translate -objc-selector fooInstanceFunc1: -pos=7:16 %s -- -F %S/../Inputs/libIDE-mock-sdk -I %t.tmp %mcp_opt %s | %FileCheck -check-prefix=CHECK3 %s
 // RUN: %sourcekitd-test -req=translate -objc-selector fooFunc3:d:d:d: -pos=8:4 %s -- -F %S/../Inputs/libIDE-mock-sdk -I %t.tmp %mcp_opt %s | %FileCheck -check-prefix=CHECK-NONE %s
 
 // RUN: %sourcekitd-test -req=translate -objc-selector fooBaseInstanceFuncOverridden1 -pos=12:13 %s -- -F %S/../Inputs/libIDE-mock-sdk -I %t.tmp %mcp_opt %s | %FileCheck -check-prefix=CHECK4 %s
@@ -42,7 +43,6 @@ func foo2 (_ a : FooClassDerived) {
 // RUN: %sourcekitd-test -req=translate -objc-selector initWithfloat2:D: -pos=17:13 %s -- -F %S/../Inputs/libIDE-mock-sdk -I %t.tmp %mcp_opt %s | %FileCheck -check-prefix=CHECK-NONE %s
 // RUN: %sourcekitd-test -req=translate -objc-selector init: -pos=17:13 %s -- -F %S/../Inputs/libIDE-mock-sdk -I %t.tmp %mcp_opt %s | %FileCheck -check-prefix=CHECK13 %s
 // RUN: %sourcekitd-test -req=translate -objc-selector iit: -pos=17:13 %s -- -F %S/../Inputs/libIDE-mock-sdk -I %t.tmp %mcp_opt %s | %FileCheck -check-prefix=CHECK13 %s
-// RUN: %sourcekitd-test -req=translate -objc-selector init: -pos=18:13 %s -- -F %S/../Inputs/libIDE-mock-sdk -I %t.tmp %mcp_opt %s | %FileCheck -check-prefix=CHECK-NONE %s
 // RUN: %sourcekitd-test -req=translate -objc-selector NAME -pos=18:13 %s -- -F %S/../Inputs/libIDE-mock-sdk -I %t.tmp %mcp_opt %s | %FileCheck -check-prefix=CHECK14 %s
 
 // CHECK1: FooClassDerived2
diff --git a/test/SourceKit/NameTranslation/init.swift b/test/SourceKit/NameTranslation/init.swift
index aaef7628dbf..4a28af32d8b 100644
--- a/test/SourceKit/NameTranslation/init.swift
+++ b/test/SourceKit/NameTranslation/init.swift
@@ -7,7 +7,7 @@ func foo2 () {
 
 // REQUIRES: objc_interop
 // RUN: %sourcekitd-test -req=translate -objc-selector initWithFloat2: -pos=4:15 %s -- -F %S/Inputs/mock-sdk -I %t.tmp %mcp_opt %s | %FileCheck -check-prefix=CHECK1 %s
-// RUN: %sourcekitd-test -req=translate -objc-selector initWithFloat2 -pos=4:15 %s -- -F %S/Inputs/mock-sdk -I %t.tmp %mcp_opt %s | %FileCheck -check-prefix=CHECK-NONE %s
+// RUN: %sourcekitd-test -req=translate -objc-selector initWithFloat2 -pos=4:15 %s -- -F %S/Inputs/mock-sdk -I %t.tmp %mcp_opt %s | %FileCheck -check-prefix=CHECK1 %s
 // RUN: %sourcekitd-test -req=translate -objc-selector initWithFloat2:second2: -pos=5:15 %s -- -F %S/Inputs/mock-sdk -I %t.tmp %mcp_opt %s | %FileCheck -check-prefix=CHECK2 %s
 // RUN: %sourcekitd-test -req=translate -objc-selector initWithFloat2:second2:third: -pos=5:15 %s -- -F %S/Inputs/mock-sdk -I %t.tmp %mcp_opt %s | %FileCheck -check-prefix=CHECK-NONE %s
 // RUN: %sourcekitd-test -req=translate -objc-selector initFloat2:second2: -pos=5:15 %s -- -F %S/Inputs/mock-sdk -I %t.tmp %mcp_opt %s | %FileCheck -check-prefix=CHECK2 %s
diff --git a/test/SourceKit/NameTranslation/swiftnames.swift b/test/SourceKit/NameTranslation/swiftnames.swift
index 38453f6ccc8..9cdb7236ce8 100644
--- a/test/SourceKit/NameTranslation/swiftnames.swift
+++ b/test/SourceKit/NameTranslation/swiftnames.swift
@@ -51,8 +51,13 @@ class C2 {}
   @objc open func /*MyClass_foo*/foo(/*MyClass_foo_p1*/bar: Int, /*MyClass_foo_p2*/baz: Int) {}
 }
 
+class C3: NSObject {
+  @objc func oneArg(_: Int) {}
+}
+
 // REQUIRES: objc_interop
 // RUN: %sourcekitd-test -req=translate -swift-name "foo(a:b:c:)" -pos=11:11 %s -- -F %S/Inputs/mock-sdk -I %t.tmp %mcp_opt %s | %FileCheck -check-prefix=CHECK1 %s
+// RUN: %sourcekitd-test -req=translate -swift-name "foo(a:b:c:)" -pos=11:11 %s -print-raw-response -- -F %S/Inputs/mock-sdk -I %t.tmp %mcp_opt %s | %FileCheck -check-prefix=CHECK_RAW1 %s
 // RUN: %sourcekitd-test -req=translate -swift-name "bar(x:y:)" -pos=11:11 %s -- -F %S/Inputs/mock-sdk -I %t.tmp %mcp_opt %s | %FileCheck -check-prefix=CHECKFEWER1 %s
 // RUN: %sourcekitd-test -req=translate -swift-name "bar(::)" -pos=11:11 %s -- -F %S/Inputs/mock-sdk -I %t.tmp %mcp_opt %s | %FileCheck -check-prefix=CHECKMISSING1 %s
 // RUN: %sourcekitd-test -req=translate -swift-name "(x:y:z:)" -pos=11:11 %s -- -F %S/Inputs/mock-sdk -I %t.tmp %mcp_opt %s | %FileCheck -check-prefix=CHECKMISSING2 %s
@@ -63,6 +68,7 @@ class C2 {}
 // RUN: %sourcekitd-test -req=translate -swift-name "foo2(a:b:c:)" -pos=12:11 %s -- -F %S/Inputs/mock-sdk -I %t.tmp %mcp_opt %s | %FileCheck -check-prefix=CHECK6 %s
 // RUN: %sourcekitd-test -req=translate -swift-name "foo2(_:_:_:)" -pos=12:11 %s -- -F %S/Inputs/mock-sdk -I %t.tmp %mcp_opt %s | %FileCheck -check-prefix=CHECK7 %s
 // RUN: %sourcekitd-test -req=translate -swift-name "foo1()" -pos=14:11 %s -- -F %S/Inputs/mock-sdk -I %t.tmp %mcp_opt %s | %FileCheck -check-prefix=CHECK8 %s
+// RUN: %sourcekitd-test -req=translate -swift-name "foo1()" -pos=14:11 %s -print-raw-response -- -F %S/Inputs/mock-sdk -I %t.tmp %mcp_opt %s | %FileCheck -check-prefix=CHECK_RAW8 %s
 // RUN: %sourcekitd-test -req=translate -swift-name "foo1(a:b:c:)" -pos=14:11 %s -- -F %S/Inputs/mock-sdk -I %t.tmp %mcp_opt %s | %FileCheck -check-prefix=CHECK-NONE %s
 // RUN: %sourcekitd-test -req=translate -swift-name "C11" -pos=1:8 %s -- -F %S/Inputs/mock-sdk -I %t.tmp %mcp_opt %s | %FileCheck -check-prefix=CHECK9 %s
 
@@ -76,6 +82,8 @@ class C2 {}
 // RUN: %sourcekitd-test -req=translate -swift-name "A2" -pos=41:10 %s -- -F %S/Inputs/mock-sdk -I %t.tmp %mcp_opt %s | %FileCheck -check-prefix=CHECK14 %s
 // RUN: %sourcekitd-test -req=translate -swift-name "C3" -pos=48:8 %s -- -F %S/Inputs/mock-sdk -I %t.tmp %mcp_opt %s | %FileCheck -check-prefix=CHECK15 %s
 // RUN: %sourcekitd-test -req=translate -swift-name "bar(_:other:)" -pos=51:36 %s -- -F %S/Inputs/mock-sdk -I %t.tmp %mcp_opt %s | %FileCheck -check-prefix=CHECK16 %s
+// RUN: %sourcekitd-test -req=translate -swift-name "zoo(m:)" -pos=55:14 %s -- -F %S/Inputs/mock-sdk -I %t.tmp %mcp_opt %s | %FileCheck -check-prefix=CHECK17 %s
+// RUN: %sourcekitd-test -req=translate -swift-name "zoo(m:)" -pos=55:14 %s -print-raw-response -- -F %S/Inputs/mock-sdk -I %t.tmp %mcp_opt %s | %FileCheck -check-prefix=CHECK_RAW17 %s
 
 // CHECK-NONE: <empty name translation info>
 // CHECK1: fooWithA:b:c:
@@ -85,7 +93,7 @@ class C2 {}
 // CHECK5: foo1:::
 // CHECK6: foo2WithA:b:c:
 // CHECK7: foo2:::
-// CHECK8: foo1
+// CHECK8: foo1{{$}}
 // CHECK9: C11
 
 // CHECK10: initWithA1:b2:
@@ -95,7 +103,24 @@ class C2 {}
 // CHECK14: CustomErrorA2
 // CHECK15: C2ObjC
 // CHECK16: bar:other:
+// CHECK17: zooWithM:
 
 // CHECKFEWER1: barWithX:y:c:
 // CHECKMISSING1: barWithA:b:c:
 // CHECKMISSING2: fooWithX:y:z:
+
+// CHECK_RAW1-LABEL: key.selectorpieces
+// CHECK_RAW1: "fooWithA"
+// CHECK_RAW1: "b"
+// CHECK_RAW1: "c"
+// CHECK_RAW1: key.namekind: source.lang.name.kind.objc
+
+// CHECK_RAW8-LABEL: key.selectorpieces
+// CHECK_RAW8: "foo1"
+// CHECK_RAW8: key.namekind: source.lang.name.kind.objc
+// CHECK_RAW8: key.is_zero_arg_selector: 1
+
+// CHECK_RAW17-LABEL: key.selectorpieces
+// CHECK_RAW17: "zooWithM"
+// CHECK_RAW17: key.namekind: source.lang.name.kind.objc
+// CHECK_RAW17-NOT: key.is_zero_arg_selector
diff --git a/tools/SourceKit/include/SourceKit/Core/LangSupport.h b/tools/SourceKit/include/SourceKit/Core/LangSupport.h
index 995ee600873..9514a114b9a 100644
--- a/tools/SourceKit/include/SourceKit/Core/LangSupport.h
+++ b/tools/SourceKit/include/SourceKit/Core/LangSupport.h
@@ -300,6 +300,7 @@ struct NameTranslatingInfo {
   UIdent NameKind;
   StringRef BaseName;
   std::vector<StringRef> ArgNames;
+  bool IsZeroArgSelector = false;
 };
 
 struct RelatedIdentsInfo {
diff --git a/tools/SourceKit/lib/SwiftLang/SwiftSourceDocInfo.cpp b/tools/SourceKit/lib/SwiftLang/SwiftSourceDocInfo.cpp
index 2bd52891ab2..4468bf58c80 100644
--- a/tools/SourceKit/lib/SwiftLang/SwiftSourceDocInfo.cpp
+++ b/tools/SourceKit/lib/SwiftLang/SwiftSourceDocInfo.cpp
@@ -900,17 +900,10 @@ getClangDeclarationName(const clang::NamedDecl *ND, NameTranslatingInfo &Info) {
   if (!Info.BaseName.empty()) {
     return clang::DeclarationName(&Ctx.Idents.get(Info.BaseName));
   } else {
-    StringRef last = Info.ArgNames.back();
-
     switch (OrigName.getNameKind()) {
     case clang::DeclarationName::ObjCZeroArgSelector:
-      if (last.endswith(":"))
-        return clang::DeclarationName();
-      break;
     case clang::DeclarationName::ObjCOneArgSelector:
     case clang::DeclarationName::ObjCMultiArgSelector:
-      if (!last.empty() && !last.endswith(":"))
-        return clang::DeclarationName();
       break;
     default:
       return clang::DeclarationName();
@@ -982,8 +975,8 @@ static bool passNameInfoForDecl(const ValueDecl *VD, NameTranslatingInfo &Info,
       if (Selector.getNumArgs()) {
         assert(Pieces.back().empty());
         Pieces.pop_back();
-        std::transform(Pieces.begin(), Pieces.end(), Pieces.begin(),
-          [](StringRef P) { return StringRef(P.data(), P.size() + 1); });
+      } else {
+        Result.IsZeroArgSelector = true;
       }
       Result.ArgNames.insert(Result.ArgNames.begin(), Pieces.begin(), Pieces.end());
       Receiver(Result);
diff --git a/tools/SourceKit/tools/sourcekitd-test/sourcekitd-test.cpp b/tools/SourceKit/tools/sourcekitd-test/sourcekitd-test.cpp
index bc5aa9d1814..f27ba1016b6 100644
--- a/tools/SourceKit/tools/sourcekitd-test/sourcekitd-test.cpp
+++ b/tools/SourceKit/tools/sourcekitd-test/sourcekitd-test.cpp
@@ -139,6 +139,7 @@ static sourcekitd_uid_t KeyRangeContent;
 static sourcekitd_uid_t KeyBaseName;
 static sourcekitd_uid_t KeyArgNames;
 static sourcekitd_uid_t KeySelectorPieces;
+static sourcekitd_uid_t KeyIsZeroArgSelector;
 static sourcekitd_uid_t KeyNameKind;
 static sourcekitd_uid_t KeySwiftVersion;
 static sourcekitd_uid_t KeyCancelOnSubsequentRequest;
@@ -271,6 +272,7 @@ static int skt_main(int argc, const char **argv) {
   KeyBaseName = sourcekitd_uid_get_from_cstr("key.basename");
   KeyArgNames = sourcekitd_uid_get_from_cstr("key.argnames");
   KeySelectorPieces = sourcekitd_uid_get_from_cstr("key.selectorpieces");
+  KeyIsZeroArgSelector = sourcekitd_uid_get_from_cstr("key.is_zero_arg_selector");
   KeyNameKind = sourcekitd_uid_get_from_cstr("key.namekind");
 
   KeySwiftVersion = sourcekitd_uid_get_from_cstr("key.swift_version");
@@ -634,15 +636,6 @@ static int handleTestInvocation(ArrayRef<const char *> Args,
       if (ArgPieces.back().empty())
         ArgPieces.pop_back();
       ArgName = KeySelectorPieces;
-      std::transform(ArgPieces.begin(), ArgPieces.end(), ArgPieces.begin(),
-        [Name] (StringRef T) {
-        if (!T.empty() && T.data() + T.size() < Name.data() + Name.size() &&
-            *(T.data() + T.size()) == ':') {
-          // Include the colon belonging to the piece.
-          return StringRef(T.data(), T.size() + 1);
-        }
-        return T;
-      });
     } else {
       llvm::errs() << "must specify either -swift-name or -objc-name or -objc-selector\n";
       return 1;
@@ -1163,6 +1156,12 @@ static void printNameTranslationInfo(sourcekitd_variant_t Info,
     Selectors.push_back(sourcekitd_variant_dictionary_get_string(Entry, KeyName));
   }
 
+  bool IsZeroArgSelector = false;
+  auto IsZeroArgObj = sourcekitd_variant_dictionary_get_value(Info, KeyIsZeroArgSelector);
+  if (sourcekitd_variant_get_type(IsZeroArgObj) != SOURCEKITD_VARIANT_TYPE_NULL) {
+    IsZeroArgSelector = sourcekitd_variant_int64_get_value(IsZeroArgObj);
+  }
+
   std::vector<const char *> Args;
   sourcekitd_variant_t ArgsObj =
     sourcekitd_variant_dictionary_get_value(Info, KeyArgNames);
@@ -1188,6 +1187,9 @@ static void printNameTranslationInfo(sourcekitd_variant_t Info,
   }
   for (auto S : Selectors) {
     OS << S;
+    if (!IsZeroArgSelector) {
+      OS << ":";
+    }
   }
   OS << '\n';
 }
diff --git a/tools/SourceKit/tools/sourcekitd/lib/API/DictionaryKeys.h b/tools/SourceKit/tools/sourcekitd/lib/API/DictionaryKeys.h
index 7baf984a3b6..ac16373dbfa 100644
--- a/tools/SourceKit/tools/sourcekitd/lib/API/DictionaryKeys.h
+++ b/tools/SourceKit/tools/sourcekitd/lib/API/DictionaryKeys.h
@@ -132,6 +132,7 @@ extern SourceKit::UIdent KeyArgNames;
 extern SourceKit::UIdent KeySelectorPieces;
 extern SourceKit::UIdent KeyNameKind;
 extern SourceKit::UIdent KeyLocalizationKey;
+extern SourceKit::UIdent KeyIsZeroArgSelector;
 
 extern SourceKit::UIdent KeySwiftVersion;
 
diff --git a/tools/SourceKit/tools/sourcekitd/lib/API/Requests.cpp b/tools/SourceKit/tools/sourcekitd/lib/API/Requests.cpp
index a5571c43828..6dc9d8b976c 100644
--- a/tools/SourceKit/tools/sourcekitd/lib/API/Requests.cpp
+++ b/tools/SourceKit/tools/sourcekitd/lib/API/Requests.cpp
@@ -1523,6 +1523,9 @@ static void reportNameInfo(const NameTranslatingInfo &Info, ResponseReceiver Rec
       NameEle.set(KeyName, N);
     }
   }
+  if (Info.IsZeroArgSelector) {
+    Elem.set(KeyIsZeroArgSelector, Info.IsZeroArgSelector);
+  }
   Rec(RespBuilder.createResponse());
 }
 
diff --git a/tools/SourceKit/tools/sourcekitd/lib/API/sourcekitdAPI-Common.cpp b/tools/SourceKit/tools/sourcekitd/lib/API/sourcekitdAPI-Common.cpp
index b5d25e11880..9eb18f5bbe7 100644
--- a/tools/SourceKit/tools/sourcekitd/lib/API/sourcekitdAPI-Common.cpp
+++ b/tools/SourceKit/tools/sourcekitd/lib/API/sourcekitdAPI-Common.cpp
@@ -145,6 +145,7 @@ UIdent sourcekitd::KeyArgNames("key.argnames");
 UIdent sourcekitd::KeySelectorPieces("key.selectorpieces");
 UIdent sourcekitd::KeyNameKind("key.namekind");
 UIdent sourcekitd::KeyLocalizationKey("key.localization_key");
+UIdent sourcekitd::KeyIsZeroArgSelector("key.is_zero_arg_selector");
 
 UIdent sourcekitd::KeySwiftVersion("key.swift_version");
 
@@ -247,6 +248,7 @@ static UIdent *OrderedKeys[] = {
   &KeySelectorPieces,
   &KeyNameKind,
   &KeyLocalizationKey,
+  &KeyIsZeroArgSelector,
 
   &KeySwiftVersion,
 };