diff --git a/include/swift/IDE/SignatureHelpFormatter.h b/include/swift/IDE/SignatureHelpFormatter.h
new file mode 100644
index 0000000000000..03e3bf43b72a6
--- /dev/null
+++ b/include/swift/IDE/SignatureHelpFormatter.h
@@ -0,0 +1,85 @@
+//===--- SignatureHelpFormatter.h --- ---------------------------*- C++ -*-===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef SWIFT_IDE_SIGNATURE_HELP_FORMATTER_H
+#define SWIFT_IDE_SIGNATURE_HELP_FORMATTER_H
+
+#include "swift/IDE/SignatureHelp.h"
+#include "llvm/ADT/ArrayRef.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/Support/Allocator.h"
+
+namespace swift {
+
+class DeclContext;
+
+namespace ide {
+
+class CodeCompletionString;
+
+struct FormattedSignatureHelp {
+  struct Parameter {
+    /// The offset of the parameter text in the signature text.
+    unsigned Offset;
+
+    /// The length of the parameter text in the signature text.
+    unsigned Length;
+
+    /// The internal parameter name.
+    llvm::StringRef Name;
+
+    Parameter() {}
+  };
+
+  struct Signature {
+    llvm::StringRef Text;
+    llvm::StringRef DocComment;
+    std::optional<unsigned> ActiveParam;
+    llvm::ArrayRef<Parameter> Params;
+
+    Signature(llvm::StringRef Text, llvm::StringRef DocComment,
+              std::optional<unsigned> ActiveParam,
+              llvm::ArrayRef<Parameter> Params)
+        : Text(Text), DocComment(DocComment), ActiveParam(ActiveParam),
+          Params(Params) {}
+  };
+
+  llvm::ArrayRef<Signature> Signatures;
+  unsigned ActiveSignature;
+
+  FormattedSignatureHelp(llvm::ArrayRef<Signature> Signatures,
+                         unsigned ActiveSignature)
+      : Signatures(Signatures), ActiveSignature(ActiveSignature) {}
+};
+
+class SignatureHelpFormatter {
+private:
+  llvm::BumpPtrAllocator &Allocator;
+
+public:
+  SignatureHelpFormatter(llvm::BumpPtrAllocator &Allocator)
+      : Allocator(Allocator) {}
+
+  FormattedSignatureHelp format(ide::SignatureHelpResult Result);
+
+private:
+  FormattedSignatureHelp::Signature
+  formatSignature(const DeclContext *DC, const ide::Signature &Signature);
+
+  CodeCompletionString *createSignatureString(const ide::Signature &Signature,
+                                              const DeclContext *DC);
+};
+
+} // namespace ide
+} // namespace swift
+
+#endif // SWIFT_IDE_SIGNATURE_HELP_FORMATTER_H
diff --git a/lib/IDE/CMakeLists.txt b/lib/IDE/CMakeLists.txt
index 9b2829d2bbaa5..cd6387ada7c0a 100644
--- a/lib/IDE/CMakeLists.txt
+++ b/lib/IDE/CMakeLists.txt
@@ -19,6 +19,7 @@ add_swift_host_library(swiftIDE STATIC
   CompletionOverrideLookup.cpp
   ConformingMethodList.cpp
   SignatureHelp.cpp
+  SignatureHelpFormatter.cpp
   CursorInfo.cpp
   ExprCompletion.cpp
   ExprContextAnalysis.cpp
diff --git a/lib/IDE/CodeCompletionResultBuilder.h b/lib/IDE/CodeCompletionResultBuilder.h
index f454cab893074..086057c3856b6 100644
--- a/lib/IDE/CodeCompletionResultBuilder.h
+++ b/lib/IDE/CodeCompletionResultBuilder.h
@@ -13,11 +13,11 @@
 #ifndef SWIFT_LIB_IDE_CODE_COMPLETION_RESULT_BUILDER_H
 #define SWIFT_LIB_IDE_CODE_COMPLETION_RESULT_BUILDER_H
 
+#include "CodeCompletionStringBuilder.h"
 #include "swift/AST/Types.h"
 #include "swift/Basic/LLVM.h"
 #include "swift/IDE/CodeCompletionResult.h"
 #include "swift/IDE/CodeCompletionResultSink.h"
-#include "swift/IDE/CodeCompletionStringBuilder.h"
 
 namespace clang {
 class Module;
diff --git a/lib/IDE/CodeCompletionStringBuilder.cpp b/lib/IDE/CodeCompletionStringBuilder.cpp
index 0379a5905c8b8..213dcdfed9a72 100644
--- a/lib/IDE/CodeCompletionStringBuilder.cpp
+++ b/lib/IDE/CodeCompletionStringBuilder.cpp
@@ -10,7 +10,7 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "swift/IDE/CodeCompletionStringBuilder.h"
+#include "CodeCompletionStringBuilder.h"
 #include "swift/AST/ASTContext.h"
 #include "swift/AST/Decl.h"
 #include "swift/AST/GenericEnvironment.h"
diff --git a/include/swift/IDE/CodeCompletionStringBuilder.h b/lib/IDE/CodeCompletionStringBuilder.h
similarity index 100%
rename from include/swift/IDE/CodeCompletionStringBuilder.h
rename to lib/IDE/CodeCompletionStringBuilder.h
diff --git a/lib/IDE/CodeCompletionStringPrinter.cpp b/lib/IDE/CodeCompletionStringPrinter.cpp
index 5c7853a9e32cf..a739b9ca7869a 100644
--- a/lib/IDE/CodeCompletionStringPrinter.cpp
+++ b/lib/IDE/CodeCompletionStringPrinter.cpp
@@ -11,9 +11,9 @@
 //===----------------------------------------------------------------------===//
 
 #include "swift/IDE/CodeCompletionStringPrinter.h"
+#include "CodeCompletionStringBuilder.h"
 #include "swift/AST/Module.h"
 #include "swift/Basic/Assertions.h"
-#include "swift/IDE/CodeCompletionStringBuilder.h"
 
 using namespace swift;
 using namespace swift::ide;
diff --git a/lib/IDE/SignatureHelpFormatter.cpp b/lib/IDE/SignatureHelpFormatter.cpp
new file mode 100644
index 0000000000000..528a7c668ddbd
--- /dev/null
+++ b/lib/IDE/SignatureHelpFormatter.cpp
@@ -0,0 +1,204 @@
+//===--- SignatureHelpFormatter.cpp --- -------------------------*- C++ -*-===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+#include "swift/IDE/SignatureHelpFormatter.h"
+#include "CodeCompletionStringBuilder.h"
+#include "swift/AST/ParameterList.h"
+#include "swift/IDE/CommentConversion.h"
+
+using namespace swift;
+using namespace swift::ide;
+
+using ChunkKind = CodeCompletionString::Chunk::ChunkKind;
+
+/// \returns Array of parameters of \p VD accounting for implicitly curried
+/// instance methods.
+static ArrayRef<const ParamDecl *>
+getParameterArray(const ValueDecl *VD, bool IsImplicitlyCurried,
+                  const ParamDecl *&Scratch) {
+  if (!VD)
+    return {};
+
+  if (IsImplicitlyCurried) {
+    auto *FD = dyn_cast<AbstractFunctionDecl>(VD);
+    assert(FD && FD->hasImplicitSelfDecl());
+
+    Scratch = FD->getImplicitSelfDecl();
+    return ArrayRef(&Scratch, 1);
+  }
+
+  if (auto *ParamList = VD->getParameterList())
+    return ParamList->getArray();
+
+  return {};
+}
+
+static StringRef copyAndClearString(llvm::BumpPtrAllocator &Allocator,
+                                    SmallVectorImpl<char> &Str) {
+  auto Ref = StringRef(Str.data(), Str.size()).copy(Allocator);
+  Str.clear();
+  return Ref;
+}
+
+CodeCompletionString *
+SignatureHelpFormatter::createSignatureString(const ide::Signature &Signature,
+                                              const DeclContext *DC) {
+  ValueDecl *FD = Signature.FuncD;
+  AnyFunctionType *AFT = Signature.FuncTy;
+
+  GenericSignature GenericSig;
+  if (FD) {
+    if (auto *GC = FD->getAsGenericContext())
+      GenericSig = GC->getGenericSignature();
+  }
+
+  CodeCompletionStringBuilder StringBuilder(
+      Allocator, /*AnnotateResults=*/false,
+      /*UnderscoreEmptyArgumentLabel=*/!Signature.IsSubscript,
+      /*FullParameterFlags=*/true);
+
+  DeclBaseName BaseName;
+
+  if (!Signature.IsSecondApply && FD) {
+    BaseName = FD->getBaseName();
+  } else if (Signature.IsSubscript) {
+    BaseName = DeclBaseName::createSubscript();
+  }
+
+  if (!BaseName.empty())
+    StringBuilder.addValueBaseName(BaseName,
+                                   /*IsMember=*/bool(Signature.BaseType));
+
+  StringBuilder.addLeftParen();
+
+  const ParamDecl *ParamScratch;
+  StringBuilder.addCallArgumentPatterns(
+      AFT->getParams(),
+      getParameterArray(FD, Signature.IsImplicitlyCurried, ParamScratch), DC,
+      GenericSig, DefaultArgumentOutputMode::All,
+      /*includeDefaultValues=*/true);
+
+  StringBuilder.addRightParen();
+
+  if (!Signature.IsImplicitlyCurried) {
+    if (Signature.IsSecondApply) {
+      // For a second apply, we don't pass the declaration to avoid adding
+      // incorrect rethrows and reasync which are only usable in a single apply.
+      StringBuilder.addEffectsSpecifiers(AFT, /*AFD=*/nullptr);
+    } else {
+      StringBuilder.addEffectsSpecifiers(
+          AFT, dyn_cast_or_null<AbstractFunctionDecl>(FD));
+    }
+  }
+
+  if (FD && FD->isImplicitlyUnwrappedOptional()) {
+    StringBuilder.addTypeAnnotationForImplicitlyUnwrappedOptional(
+        AFT->getResult(), DC, GenericSig);
+  } else {
+    StringBuilder.addTypeAnnotation(AFT->getResult(), DC, GenericSig);
+  }
+
+  return StringBuilder.createCompletionString();
+}
+
+FormattedSignatureHelp::Signature
+SignatureHelpFormatter::formatSignature(const DeclContext *DC,
+                                        const ide::Signature &Signature) {
+  auto *FD = Signature.FuncD;
+  auto *AFT = Signature.FuncTy;
+
+  bool IsConstructor = isa_and_nonnull<ConstructorDecl>(FD);
+
+  auto *SignatureString = createSignatureString(Signature, DC);
+
+  llvm::SmallString<512> SS;
+  llvm::raw_svector_ostream OS(SS);
+
+  bool SkipResult = AFT->getResult()->isVoid() || IsConstructor;
+
+  SmallVector<FormattedSignatureHelp::Parameter, 8> FormattedParams;
+
+  auto Chunks = SignatureString->getChunks();
+  auto C = Chunks.begin();
+  while (C != Chunks.end()) {
+    if (C->is(ChunkKind::TypeAnnotation) && SkipResult) {
+      ++C;
+      continue;
+    }
+
+    if (C->is(ChunkKind::TypeAnnotation))
+      OS << " -> ";
+
+    if (C->is(ChunkKind::CallArgumentBegin)) {
+      unsigned NestingLevel = C->getNestingLevel();
+      ++C;
+
+      auto &P = FormattedParams.emplace_back();
+      P.Offset = SS.size();
+
+      do {
+        if (!C->is(ChunkKind::CallArgumentClosureType) && C->hasText())
+          OS << C->getText();
+
+        ++C;
+      } while (C != Chunks.end() && !C->endsPreviousNestedGroup(NestingLevel));
+
+      P.Length = SS.size() - P.Offset;
+      continue;
+    }
+
+    if (C->hasText())
+      OS << C->getText();
+
+    ++C;
+  }
+
+  StringRef SignatureText = copyAndClearString(Allocator, SS);
+
+  // Parameter names.
+  const ParamDecl *ParamScratch;
+  auto ParamDecls =
+      getParameterArray(FD, Signature.IsImplicitlyCurried, ParamScratch);
+
+  if (!ParamDecls.empty()) {
+    for (unsigned i = 0; i < FormattedParams.size(); ++i) {
+      FormattedParams[i].Name = ParamDecls[i]->getParameterName().str();
+    }
+  }
+
+  // Documentation.
+  StringRef DocComment;
+  if (FD) {
+    ide::getRawDocumentationComment(FD, OS);
+    DocComment = copyAndClearString(Allocator, SS);
+  }
+
+  return FormattedSignatureHelp::Signature(
+      SignatureText, DocComment, Signature.ParamIdx,
+      ArrayRef(FormattedParams).copy(Allocator));
+}
+
+FormattedSignatureHelp
+SignatureHelpFormatter::format(SignatureHelpResult Result) {
+  SmallVector<FormattedSignatureHelp::Signature, 8> FormattedSignatures;
+  FormattedSignatures.reserve(Result.Signatures.size());
+
+  for (auto &Signature : Result.Signatures) {
+    FormattedSignatures.push_back(formatSignature(Result.DC, Signature));
+  }
+
+  // FIXME: Ideally we should select an active signature based on the context.
+  unsigned ActiveSignature = 0;
+
+  return FormattedSignatureHelp(ArrayRef(FormattedSignatures).copy(Allocator),
+                                ActiveSignature);
+}
diff --git a/test/IDE/signature_help_closure_param.swift b/test/IDE/signature_help_closure_param.swift
new file mode 100644
index 0000000000000..9a04515e53d88
--- /dev/null
+++ b/test/IDE/signature_help_closure_param.swift
@@ -0,0 +1,7 @@
+// RUN: %target-swift-ide-test -signature-help -code-completion-token=CLOSURE_PARAM -source-filename=%s | %FileCheck %s --check-prefix=CLOSURE_PARAM
+
+func apply<Value, Result>(value: Value, body: (Value) -> Result) -> Result {
+  return body(#^CLOSURE_PARAM^#)
+  // CLOSURE_PARAM:     Begin signatures, 1 items
+  // CLOSURE_PARAM-DAG: Signature[Active]: body(<param active>Value</param>) -> Result
+}
diff --git a/test/IDE/signature_help_currying.swift b/test/IDE/signature_help_currying.swift
new file mode 100644
index 0000000000000..910a781f37a38
--- /dev/null
+++ b/test/IDE/signature_help_currying.swift
@@ -0,0 +1,74 @@
+// RUN: %target-swift-ide-test -signature-help -code-completion-token=CURRY_TOPLEVEL -source-filename=%s | %FileCheck %s --check-prefix=CURRY_TOPLEVEL
+// RUN: %target-swift-ide-test -signature-help -code-completion-token=CURRY_MEMBER_PARTIAL -source-filename=%s | %FileCheck %s --check-prefix=CURRY_MEMBER_PARTIAL
+// RUN: %target-swift-ide-test -signature-help -code-completion-token=CURRY_MEMBER_FULL -source-filename=%s | %FileCheck %s --check-prefix=CURRY_MEMBER_FULL
+
+struct Adder {
+  func add(_ x: Int, to y: Int) -> Int {
+    return x + y
+  }
+
+  func add(oneTo x: inout Int) {
+    x += 1
+  }
+
+  func add<T: AdditiveArithmetic>(_ x: T, to y: T) -> T {
+    return x + y
+  }
+
+  func add(first: Double!, second: Float, third: Int) -> Double {
+    return first + Double(second) + Double(third)
+  }
+
+  func add(arg1 param1: Double, arg2: Float, arg3 param3: Int) -> Double {
+    return param1 + Double(arg2) + Double(param3)
+  }
+
+  func add(numbers: Double...) -> Double {
+    return numbers.reduce(into: 0) { $0 += $1 }
+  }
+
+  func add(x: Int, y: Int, with adder: (Int, Int) throws -> Int) rethrows -> Int! {
+    return try adder(x, y)
+  }
+
+  func add(x: Int) -> (Int) -> Int {
+    return { (y: Int) in x + y }
+  }
+}
+
+func topLevelCurried(x: Int) -> (Double) -> (String) -> Void {
+  fatalError()
+}
+
+func testCurryTopLevel() {
+  topLevelCurried(x: 1)(#^CURRY_TOPLEVEL^#)
+  // CURRY_TOPLEVEL:     Begin signatures, 1 items
+  // CURRY_TOPLEVEL-DAG: Signature[Active]: (<param active>Double</param>) -> (String) -> Void
+}
+
+func testCurryMemberPartial() {
+  Adder.add(#^CURRY_MEMBER_PARTIAL^#)
+  // CURRY_MEMBER_PARTIAL:     Begin signatures, 8 items
+  // CURRY_MEMBER_PARTIAL-DAG: Signature[Active]: add(<param name="self" active>_ self: Adder</param>) -> (Int, Int) -> Int
+  // CURRY_MEMBER_PARTIAL-DAG: Signature: add(<param name="self" active>_ self: Adder</param>) -> (inout Int) -> ()
+  // CURRY_MEMBER_PARTIAL-DAG: Signature: add(<param name="self" active>_ self: Adder</param>) -> (AdditiveArithmetic, AdditiveArithmetic) -> AdditiveArithmetic
+  // CURRY_MEMBER_PARTIAL-DAG: Signature: add(<param name="self" active>_ self: Adder</param>) -> (Double?, Float, Int) -> Double
+  // CURRY_MEMBER_PARTIAL-DAG: Signature: add(<param name="self" active>_ self: Adder</param>) -> (Double, Float, Int) -> Double
+  // CURRY_MEMBER_PARTIAL-DAG: Signature: add(<param name="self" active>_ self: Adder</param>) -> (Double...) -> Double
+  // CURRY_MEMBER_PARTIAL-DAG: Signature: add(<param name="self" active>_ self: Adder</param>) -> (Int, Int, (Int, Int) throws -> Int) throws -> Int?
+  // CURRY_MEMBER_PARTIAL-DAG: Signature: add(<param name="self" active>_ self: Adder</param>) -> (Int) -> (Int) -> Int
+}
+
+func testCurryMemberFull() {
+  let adder = Adder()
+  Adder.add(adder)(#^CURRY_MEMBER_FULL^#)
+  // CURRY_MEMBER_FULL:     Begin signatures, 8 items
+  // CURRY_MEMBER_FULL-DAG: Signature[Active]: (<param name="x" active>_ x: Int</param>, <param name="y">to: Int</param>) -> Int
+  // CURRY_MEMBER_FULL-DAG: Signature: (<param name="x" active>oneTo: inout Int</param>)
+  // CURRY_MEMBER_FULL-DAG: Signature: (<param name="x" active>_ x: AdditiveArithmetic</param>, <param name="y">to: AdditiveArithmetic</param>) -> AdditiveArithmetic
+  // CURRY_MEMBER_FULL-DAG: Signature: (<param name="first" active>first: Double!</param>, <param name="second">second: Float</param>, <param name="third">third: Int</param>) -> Double
+  // CURRY_MEMBER_FULL-DAG: Signature: (<param name="param1" active>arg1: Double</param>, <param name="arg2">arg2: Float</param>, <param name="param3">arg3: Int</param>) -> Double
+  // CURRY_MEMBER_FULL-DAG: Signature: (<param name="numbers" active>numbers: Double...</param>) -> Double
+  // CURRY_MEMBER_FULL-DAG: Signature: (<param name="x" active>x: Int</param>, <param name="y">y: Int</param>, <param name="adder">with: (Int, Int) throws -> Int</param>) throws -> Int!
+  // CURRY_MEMBER_FULL-DAG: Signature: (<param name="x" active>x: Int</param>) -> (Int) -> Int
+}
diff --git a/test/IDE/signature_help_default_args.swift b/test/IDE/signature_help_default_args.swift
new file mode 100644
index 0000000000000..0e07b2db06e02
--- /dev/null
+++ b/test/IDE/signature_help_default_args.swift
@@ -0,0 +1,34 @@
+// RUN: %target-swift-ide-test -signature-help -code-completion-token=DEFAULT_ARGS -source-filename=%s | %FileCheck %s --check-prefix=DEFAULT_ARGS
+
+func add(_ x: Int = 10, to y: Int) -> Int {}
+
+func add(oneTo x: inout Int) {}
+
+func add(_ x: Int, to y: Int? = nil) -> String {}
+
+func add(first: Double!, second: Float = .pi, third: Int) -> Double {}
+
+struct S {
+  let a: Bool
+}
+
+func add(s: S = S(a: false)) -> Double {}
+
+func add(x: Int, y: Int, with adder: (Int, Int) -> Int = { $0 + $1 }) -> Int {}
+
+let importantValue = 42
+
+func add(x: Int = importantValue) {}
+
+func add(x: Int, line: UInt = #line, file: StaticString = #file) {}
+
+add(#^DEFAULT_ARGS^#)
+// DEFAULT_ARGS:     Begin signatures, 8 items
+// DEFAULT_ARGS-DAG: Signature[Active]: add(<param name="x" active>_ x: Int = 10</param>, <param name="y">to: Int</param>) -> Int
+// DEFAULT_ARGS-DAG: Signature: add(<param name="x" active>oneTo: inout Int</param>)
+// DEFAULT_ARGS-DAG: Signature: add(<param name="x" active>_ x: Int</param>, <param name="y">to: Int? = nil</param>) -> String
+// DEFAULT_ARGS-DAG: Signature: add(<param name="first" active>first: Double!</param>, <param name="second">second: Float = .pi</param>, <param name="third">third: Int</param>) -> Double
+// DEFAULT_ARGS-DAG: Signature: add(<param name="s" active>s: S = S(a: false)</param>) -> Double
+// DEFAULT_ARGS-DAG: Signature: add(<param name="x" active>x: Int</param>, <param name="y">y: Int</param>, <param name="adder">with: (Int, Int) -> Int = { $0 + $1 }</param>) -> Int
+// DEFAULT_ARGS-DAG: Signature: add(<param name="x" active>x: Int = importantValue</param>)
+// DEFAULT_ARGS-DAG: Signature: add(<param name="x" active>x: Int</param>, <param name="line">line: UInt = #line</param>, <param name="file">file: StaticString = #file</param>)
diff --git a/test/IDE/signature_help_doc.swift b/test/IDE/signature_help_doc.swift
new file mode 100644
index 0000000000000..6c741b34051c5
--- /dev/null
+++ b/test/IDE/signature_help_doc.swift
@@ -0,0 +1,21 @@
+// RUN: %target-swift-ide-test -signature-help -code-completion-token=DOC -source-filename=%s | %FileCheck %s --check-prefix=DOC
+
+/// Adds two integers.
+///
+/// - Parameters:
+///   - x: The first integer to add.
+///   - y: The second integer to add.
+///
+/// Usage:
+/// ```swift
+/// add(1, to: 2) // 3
+/// ```
+///
+/// - Returns: The sum of the two integers.
+func add(_ x: Int, to y: Int) -> Int {
+  return x + y
+}
+
+add(#^DOC^#)
+// DOC:     Begin signatures, 1 items
+// DOC-DAG: Signature[Active]: add(<param name="x" active>_ x: Int</param>, <param name="y">to: Int</param>) -> Int; Documentation=Adds two integers.\n\n- Parameters:\n  - x: The first integer to add.\n  - y: The second integer to add.\n\nUsage:\n```swift\nadd(1, to: 2) // 3\n```\n\n- Returns: The sum of the two integers.
diff --git a/test/IDE/signature_help_enum_case.swift b/test/IDE/signature_help_enum_case.swift
new file mode 100644
index 0000000000000..b315676f4f518
--- /dev/null
+++ b/test/IDE/signature_help_enum_case.swift
@@ -0,0 +1,19 @@
+// RUN: %target-swift-ide-test -signature-help -code-completion-token=LABELLED -source-filename=%s | %FileCheck %s --check-prefix=LABELLED
+// RUN: %target-swift-ide-test -signature-help -code-completion-token=UNLABELLED -source-filename=%s | %FileCheck %s --check-prefix=UNLABELLED
+
+enum Barcode {
+  case upc(numberSystem: Int, manufacturer: Int, product: Int, check: Int)
+  case qrCode(String)
+}
+
+func testLabeled() {
+  Barcode.upc(#^LABELLED^#, manufacturer: 85909, product: 51226, check: 3)
+  // LABELLED:     Begin signatures, 1 items
+  // LABELLED-DAG: Signature[Active]: upc(<param name="numberSystem" active>numberSystem: Int</param>, <param name="manufacturer">manufacturer: Int</param>, <param name="product">product: Int</param>, <param name="check">check: Int</param>) -> Barcode
+}
+
+func testUnlabled() {
+  Barcode.qrCode(#^UNLABELLED^#)
+  // UNLABELLED:     Begin signatures, 1 items
+  // UNLABELLED-DAG: Signature[Active]: qrCode(<param active>String</param>) -> Barcode
+}
diff --git a/test/IDE/signature_help_init.swift b/test/IDE/signature_help_init.swift
new file mode 100644
index 0000000000000..dd80e94b2cd28
--- /dev/null
+++ b/test/IDE/signature_help_init.swift
@@ -0,0 +1,9 @@
+// RUN: %target-swift-ide-test -signature-help -code-completion-token=INIT -source-filename=%s | %FileCheck %s --check-prefix=INIT
+
+struct Person {
+  init(name: String, age: Int, profession job: String) { }
+}
+
+Person(name: "John", age: #^INIT^#)
+// INIT:     Begin signatures, 1 items
+// INIT-DAG: Signature[Active]: init(<param name="name">name: String</param>, <param name="age" active>age: Int</param>, <param name="job">profession: String</param>)
diff --git a/test/IDE/signature_help_member_closure.swift b/test/IDE/signature_help_member_closure.swift
new file mode 100644
index 0000000000000..8e175a29f5066
--- /dev/null
+++ b/test/IDE/signature_help_member_closure.swift
@@ -0,0 +1,11 @@
+// RUN: %target-swift-ide-test -signature-help -code-completion-token=MEMBER_CLOSURE -source-filename=%s | %FileCheck %s --check-prefix=MEMBER_CLOSURE
+
+struct Observable {
+  var observer: (String, Int?, [AnyHashable: [Double?]]) async throws -> [Observable?]
+  
+  func notify() async throws {
+    _ = try await observer("EVENT", #^MEMBER_CLOSURE^#, [:])
+    // MEMBER_CLOSURE:     Begin signatures, 1 items
+    // MEMBER_CLOSURE-DAG: Signature[Active]: observer(<param>String</param>, <param active>Int?</param>, <param>[AnyHashable : [Double?]]</param>) async throws -> [Observable?]
+  }
+}
diff --git a/test/IDE/signature_help_member_func.swift b/test/IDE/signature_help_member_func.swift
new file mode 100644
index 0000000000000..46cd62dedb8ee
--- /dev/null
+++ b/test/IDE/signature_help_member_func.swift
@@ -0,0 +1,47 @@
+// RUN: %target-swift-ide-test -signature-help -code-completion-token=MEMBER_FUNC -source-filename=%s | %FileCheck %s --check-prefix=MEMBER_FUNC
+
+struct Adder {
+  func add(_ x: Int, to y: Int) -> Int {
+    return x + y
+  }
+  
+  func add(oneTo x: inout Int) {
+    x += 1
+  }
+  
+  func add<T: AdditiveArithmetic>(_ x: T, to y: T) -> T {
+    return x + y
+  }
+  
+  func add(first: Double!, second: Float, third: Int) -> Double {
+    return first + Double(second) + Double(third)
+  }
+  
+  func add(arg1 param1: Double, arg2: Float, arg3 param3: Int) -> Double {
+    return param1 + Double(arg2) + Double(param3)
+  }
+  
+  func add(numbers: Double...) -> Double {
+    return numbers.reduce(into: 0) { $0 += $1 }
+  }
+  
+  func add(x: Int, y: Int, with adder: (Int, Int) -> Int) -> Int {
+    return adder(x, y)
+  }
+  
+  func add(x: Int) -> (Int) -> Int {
+    return { (y: Int) in x + y }
+  }
+}
+
+let adder = Adder()
+adder.add(#^MEMBER_FUNC^#)
+// MEMBER_FUNC:     Begin signatures, 8 items
+// MEMBER_FUNC-DAG: Signature[Active]: add(<param name="x" active>_ x: Int</param>, <param name="y">to: Int</param>) -> Int
+// MEMBER_FUNC-DAG: Signature: add(<param name="x" active>oneTo: inout Int</param>)
+// MEMBER_FUNC-DAG: Signature: add(<param name="x" active>_ x: AdditiveArithmetic</param>, <param name="y">to: AdditiveArithmetic</param>) -> AdditiveArithmetic
+// MEMBER_FUNC-DAG: Signature: add(<param name="first" active>first: Double!</param>, <param name="second">second: Float</param>, <param name="third">third: Int</param>) -> Double
+// MEMBER_FUNC-DAG: Signature: add(<param name="param1" active>arg1: Double</param>, <param name="arg2">arg2: Float</param>, <param name="param3">arg3: Int</param>) -> Double
+// MEMBER_FUNC-DAG: Signature: add(<param name="numbers" active>numbers: Double...</param>) -> Double
+// MEMBER_FUNC-DAG: Signature: add(<param name="x" active>x: Int</param>, <param name="y">y: Int</param>, <param name="adder">with: (Int, Int) -> Int</param>) -> Int
+// MEMBER_FUNC-DAG: Signature: add(<param name="x" active>x: Int</param>) -> (Int) -> Int
diff --git a/test/IDE/signature_help_member_generic.swift b/test/IDE/signature_help_member_generic.swift
new file mode 100644
index 0000000000000..291dfa59a4c9e
--- /dev/null
+++ b/test/IDE/signature_help_member_generic.swift
@@ -0,0 +1,12 @@
+// RUN: %target-swift-ide-test -signature-help -code-completion-token=MEMBER_GENERIC -source-filename=%s | %FileCheck %s --check-prefix=MEMBER_GENERIC
+
+struct Vector<Value> {
+  init(elements: [Value]) { }
+  
+  func dot(with other: Vector<Value>) -> Value { fatalError() }
+}
+
+let vec = Vector(elements: [1.0, 2.1, 3.4])
+vec.dot(with: #^MEMBER_GENERIC^#)
+// MEMBER_GENERIC:     Begin signatures, 1 items
+// MEMBER_GENERIC-DAG: Signature[Active]: dot(<param name="other" active>with: Vector<Double></param>) -> Double
diff --git a/test/IDE/signature_help_member_subscript.swift b/test/IDE/signature_help_member_subscript.swift
new file mode 100644
index 0000000000000..3dca0ddb1dc03
--- /dev/null
+++ b/test/IDE/signature_help_member_subscript.swift
@@ -0,0 +1,23 @@
+// RUN: %target-swift-ide-test -signature-help -code-completion-token=MEMBER_SUBSCRIPT -source-filename=%s | %FileCheck %s --check-prefix=MEMBER_SUBSCRIPT
+
+struct Matrix {
+  subscript(row: Int, column: Int) -> Int {
+    return 0
+  }
+  
+  subscript(row r: Int) -> [Int] {
+    return []
+  }
+  
+  subscript(column c: Int) -> [Int] {
+    return []
+  }
+}
+
+let matrix = Matrix()
+matrix[#^MEMBER_SUBSCRIPT^#]
+// MEMBER_SUBSCRIPT:     Begin signatures, 4 items
+// MEMBER_SUBSCRIPT-DAG: Signature[Active]: subscript(<param active>keyPath: KeyPath<Matrix, Value></param>) -> Value
+// MEMBER_SUBSCRIPT-DAG: Signature: subscript(<param name="row" active>row: Int</param>, <param name="column">column: Int</param>) -> Int
+// MEMBER_SUBSCRIPT-DAG: Signature: subscript(<param name="r" active>row: Int</param>) -> [Int]
+// MEMBER_SUBSCRIPT-DAG: Signature: subscript(<param name="c" active>column: Int</param>) -> [Int]
diff --git a/test/IDE/signature_help_raw_identifier.swift b/test/IDE/signature_help_raw_identifier.swift
new file mode 100644
index 0000000000000..72c00378a95f3
--- /dev/null
+++ b/test/IDE/signature_help_raw_identifier.swift
@@ -0,0 +1,9 @@
+// RUN: %target-swift-ide-test -signature-help -code-completion-token=RAW_ID -source-filename=%s | %FileCheck %s --check-prefix=RAW_ID
+
+struct `Raw Identifier` {
+  func `some method :)`(`argument label!` `param label?`: Int) {}
+}
+
+`Raw Identifier`().`some method :)`(#^RAW_ID^#)
+// RAW_ID:     Begin signatures, 1 items
+// RAW_ID-DAG: Signature[Active]: `some method :)`(<param name="param label?" active>`argument label!`: Int</param>)
diff --git a/test/IDE/signature_help_top_level.swift b/test/IDE/signature_help_top_level.swift
new file mode 100644
index 0000000000000..f5e0bdb787c8d
--- /dev/null
+++ b/test/IDE/signature_help_top_level.swift
@@ -0,0 +1,44 @@
+// RUN: %target-swift-ide-test -signature-help -code-completion-token=TOP_LEVEL -source-filename=%s | %FileCheck %s --check-prefix=TOP_LEVEL
+
+func add(_ x: Int, to y: Int) -> Int {
+  return x + y
+}
+
+func add(oneTo x: inout Int) {
+  x += 1
+}
+
+func add<T: AdditiveArithmetic>(_ x: T, to y: T) -> T {
+  return x + y
+}
+
+func add(first: Double!, second: Float, third: Int) -> Double {
+  return first + Double(second) + Double(third)
+}
+
+func add(arg1 param1: Double, arg2: Float, arg3 param3: Int) -> Double {
+  return param1 + Double(arg2) + Double(param3)
+}
+
+func add(numbers: Double...) -> Double {
+  return numbers.reduce(into: 0) { $0 += $1 }
+}
+
+func add(x: Int, y: Int, with adder: (Int, Int) -> Int) -> Int {
+  return adder(x, y)
+}
+
+func add(x: Int) -> (Int) -> Int {
+  return { (y: Int) in x + y }
+}
+
+add(#^TOP_LEVEL^#)
+// TOP_LEVEL:     Begin signatures, 8 items
+// TOP_LEVEL-DAG: Signature[Active]: add(<param name="x" active>_ x: Int</param>, <param name="y">to: Int</param>) -> Int
+// TOP_LEVEL-DAG: Signature: add(<param name="x" active>oneTo: inout Int</param>)
+// TOP_LEVEL-DAG: Signature: add(<param name="x" active>_ x: AdditiveArithmetic</param>, <param name="y">to: AdditiveArithmetic</param>) -> AdditiveArithmetic
+// TOP_LEVEL-DAG: Signature: add(<param name="first" active>first: Double!</param>, <param name="second">second: Float</param>, <param name="third">third: Int</param>) -> Double
+// TOP_LEVEL-DAG: Signature: add(<param name="param1" active>arg1: Double</param>, <param name="arg2">arg2: Float</param>, <param name="param3">arg3: Int</param>) -> Double
+// TOP_LEVEL-DAG: Signature: add(<param name="numbers" active>numbers: Double...</param>) -> Double
+// TOP_LEVEL-DAG: Signature: add(<param name="x" active>x: Int</param>, <param name="y">y: Int</param>, <param name="adder">with: (Int, Int) -> Int</param>) -> Int
+// TOP_LEVEL-DAG: Signature: add(<param name="x" active>x: Int</param>) -> (Int) -> Int
diff --git a/test/IDE/signature_help_top_level_generic.swift b/test/IDE/signature_help_top_level_generic.swift
new file mode 100644
index 0000000000000..af9640d898d3f
--- /dev/null
+++ b/test/IDE/signature_help_top_level_generic.swift
@@ -0,0 +1,9 @@
+// RUN: %target-swift-ide-test -signature-help -code-completion-token=TOP_LEVEL_GENERIC -source-filename=%s | %FileCheck %s --check-prefix=TOP_LEVEL_GENERIC
+
+func add<T>(x: T, y: T, with adder: (T, T) -> T) -> T where T: AdditiveArithmetic {
+  return adder(x, y)
+}
+
+add(x: "A", y: "B", with: #^TOP_LEVEL_GENERIC^#)
+// TOP_LEVEL_GENERIC:     Begin signatures, 1 items
+// TOP_LEVEL_GENERIC-DAG: Signature[Active]: add(<param name="x">x: String</param>, <param name="y">y: String</param>, <param name="adder" active>with: (String, String) -> String</param>) -> String
diff --git a/test/SourceKit/SignatureHelp/signature_help.swift b/test/SourceKit/SignatureHelp/signature_help.swift
new file mode 100644
index 0000000000000..e6bc51c1fb0a7
--- /dev/null
+++ b/test/SourceKit/SignatureHelp/signature_help.swift
@@ -0,0 +1,64 @@
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t
+// RUN: %sourcekitd-test -req=signaturehelp -pos=18:10 %t/input.swift -- %t/input.swift > %t/actual.result
+// RUN: diff -u %t/expected.result %t/actual.result
+
+//--- input.swift
+struct Calculator {
+  /// Adds two numbers together.
+  ///
+  /// - Parameters:
+  ///   - x: The first number to add.
+  ///   - y: The second number to add.
+  /// - Returns: The sum of x and y.
+  func add(_ x: Int, to y: Int) -> Int {
+    return x + y
+  }
+  
+  func add(first: Double, second: Float) -> Double {
+    return first + Double(second)
+  }
+}
+
+let calc = Calculator()
+calc.add()
+
+//--- expected.result
+{
+  key.signatures: [
+    {
+      key.name: "add(_ x: Int, to: Int) -> Int",
+      key.doc_comment: "Adds two numbers together.\n\n- Parameters:\n  - x: The first number to add.\n  - y: The second number to add.\n- Returns: The sum of x and y.",
+      key.parameters: [
+        {
+          key.name: "x",
+          key.nameoffset: 4,
+          key.namelength: 8
+        },
+        {
+          key.name: "y",
+          key.nameoffset: 14,
+          key.namelength: 7
+        }
+      ],
+      key.active_parameter: 0
+    },
+    {
+      key.name: "add(first: Double, second: Float) -> Double",
+      key.parameters: [
+        {
+          key.name: "first",
+          key.nameoffset: 4,
+          key.namelength: 13
+        },
+        {
+          key.name: "second",
+          key.nameoffset: 19,
+          key.namelength: 13
+        }
+      ],
+      key.active_parameter: 0
+    }
+  ],
+  key.active_signature: 0
+}
diff --git a/test/SourceKit/SignatureHelp/signature_help_closure_param.swift b/test/SourceKit/SignatureHelp/signature_help_closure_param.swift
deleted file mode 100644
index f2edff368c4b0..0000000000000
--- a/test/SourceKit/SignatureHelp/signature_help_closure_param.swift
+++ /dev/null
@@ -1,26 +0,0 @@
-// RUN: %empty-directory(%t)
-// RUN: split-file %s %t
-// RUN: %sourcekitd-test -req=signaturehelp -pos=2:15 %t/input.swift -- %t/input.swift > %t/actual.result
-// RUN: diff -u %t/expected.result %t/actual.result
-
-//--- input.swift
-func apply<Value, Result>(value: Value, body: (Value) -> Result) -> Result {
-  return body()
-}
-
-//--- expected.result
-{
-  key.signatures: [
-    {
-      key.name: "body(Value) -> Result",
-      key.parameters: [
-        {
-          key.nameoffset: 5,
-          key.namelength: 5
-        }
-      ],
-      key.active_parameter: 0
-    }
-  ],
-  key.active_signature: 0
-}
diff --git a/test/SourceKit/SignatureHelp/signature_help_currying.swift b/test/SourceKit/SignatureHelp/signature_help_currying.swift
deleted file mode 100644
index cb1de9c00d238..0000000000000
--- a/test/SourceKit/SignatureHelp/signature_help_currying.swift
+++ /dev/null
@@ -1,305 +0,0 @@
-// RUN: %empty-directory(%t)
-// RUN: split-file %s %t
-// RUN: %sourcekitd-test -req=signaturehelp -pos=40:25 %t/input.swift -- %t/input.swift > %t/actual_curry_toplevel.result
-// RUN: diff -u %t/expected_curry_toplevel.result %t/actual_curry_toplevel.result
-// RUN: %sourcekitd-test -req=signaturehelp -pos=44:13 %t/input.swift -- %t/input.swift > %t/actual_curry_member_partial.result
-// RUN: diff -u %t/expected_curry_member_partial.result %t/actual_curry_member_partial.result
-// RUN: %sourcekitd-test -req=signaturehelp -pos=49:20 %t/input.swift -- %t/input.swift > %t/actual_curry_member_full.result
-// RUN: diff -u %t/expected_curry_member_full.result %t/actual_curry_member_full.result
-
-//--- input.swift
-struct Adder {
-  func add(_ x: Int, to y: Int) -> Int {
-    return x + y
-  }
-
-  func add(oneTo x: inout Int) {
-    x += 1
-  }
-
-  func add<T: AdditiveArithmetic>(_ x: T, to y: T) -> T {
-    return x + y
-  }
-
-  func add(first: Double!, second: Float, third: Int) -> Double {
-    return first + Double(second) + Double(third)
-  }
-
-  func add(arg1 param1: Double, arg2: Float, arg3 param3: Int) -> Double {
-    return param1 + Double(arg2) + Double(param3)
-  }
-
-  func add(numbers: Double...) -> Double {
-    return numbers.reduce(into: 0) { $0 += $1 }
-  }
-
-  func add(x: Int, y: Int, with adder: (Int, Int) throws -> Int) rethrows -> Int! {
-    return adder(x, y)
-  }
-
-  func add(x: Int) -> (Int) -> Int {
-    return { (y: Int) in x + y }
-  }
-}
-
-func topLevelCurried(x: Int) -> (Double) -> (String) -> Void {
-  fatalError()
-}
-
-func testCurryTopLevel() {
-  topLevelCurried(x: 1)()
-}
-
-func testCurryMemberPartial() {
-  Adder.add()
-}
-
-func testCurryMemberFull() {
-  let adder = Adder()
-  Adder.add(adder)()
-}
-
-//--- expected_curry_toplevel.result
-{
-  key.signatures: [
-    {
-      key.name: "(Double) -> (String) -> Void",
-      key.parameters: [
-        {
-          key.nameoffset: 1,
-          key.namelength: 6
-        }
-      ],
-      key.active_parameter: 0
-    }
-  ],
-  key.active_signature: 0
-}
-//--- expected_curry_member_partial.result
-{
-  key.signatures: [
-    {
-      key.name: "add(_ self: Adder) -> (Int, Int) -> Int",
-      key.parameters: [
-        {
-          key.name: "self",
-          key.nameoffset: 4,
-          key.namelength: 13
-        }
-      ],
-      key.active_parameter: 0
-    },
-    {
-      key.name: "add(_ self: Adder) -> (inout Int) -> ()",
-      key.parameters: [
-        {
-          key.name: "self",
-          key.nameoffset: 4,
-          key.namelength: 13
-        }
-      ],
-      key.active_parameter: 0
-    },
-    {
-      key.name: "add(_ self: Adder) -> (AdditiveArithmetic, AdditiveArithmetic) -> AdditiveArithmetic",
-      key.parameters: [
-        {
-          key.name: "self",
-          key.nameoffset: 4,
-          key.namelength: 13
-        }
-      ],
-      key.active_parameter: 0
-    },
-    {
-      key.name: "add(_ self: Adder) -> (Double?, Float, Int) -> Double",
-      key.parameters: [
-        {
-          key.name: "self",
-          key.nameoffset: 4,
-          key.namelength: 13
-        }
-      ],
-      key.active_parameter: 0
-    },
-    {
-      key.name: "add(_ self: Adder) -> (Double, Float, Int) -> Double",
-      key.parameters: [
-        {
-          key.name: "self",
-          key.nameoffset: 4,
-          key.namelength: 13
-        }
-      ],
-      key.active_parameter: 0
-    },
-    {
-      key.name: "add(_ self: Adder) -> (Double...) -> Double",
-      key.parameters: [
-        {
-          key.name: "self",
-          key.nameoffset: 4,
-          key.namelength: 13
-        }
-      ],
-      key.active_parameter: 0
-    },
-    {
-      key.name: "add(_ self: Adder) -> (Int, Int, (Int, Int) throws -> Int) throws -> Int?",
-      key.parameters: [
-        {
-          key.name: "self",
-          key.nameoffset: 4,
-          key.namelength: 13
-        }
-      ],
-      key.active_parameter: 0
-    },
-    {
-      key.name: "add(_ self: Adder) -> (Int) -> (Int) -> Int",
-      key.parameters: [
-        {
-          key.name: "self",
-          key.nameoffset: 4,
-          key.namelength: 13
-        }
-      ],
-      key.active_parameter: 0
-    }
-  ],
-  key.active_signature: 0
-}
-//--- expected_curry_member_full.result
-{
-  key.signatures: [
-    {
-      key.name: "(_ x: Int, to: Int) -> Int",
-      key.parameters: [
-        {
-          key.name: "x",
-          key.nameoffset: 1,
-          key.namelength: 8
-        },
-        {
-          key.name: "y",
-          key.nameoffset: 11,
-          key.namelength: 7
-        }
-      ],
-      key.active_parameter: 0
-    },
-    {
-      key.name: "(oneTo: inout Int)",
-      key.parameters: [
-        {
-          key.name: "x",
-          key.nameoffset: 1,
-          key.namelength: 16
-        }
-      ],
-      key.active_parameter: 0
-    },
-    {
-      key.name: "(_ x: AdditiveArithmetic, to: AdditiveArithmetic) -> AdditiveArithmetic",
-      key.parameters: [
-        {
-          key.name: "x",
-          key.nameoffset: 1,
-          key.namelength: 23
-        },
-        {
-          key.name: "y",
-          key.nameoffset: 26,
-          key.namelength: 22
-        }
-      ],
-      key.active_parameter: 0
-    },
-    {
-      key.name: "(first: Double!, second: Float, third: Int) -> Double",
-      key.parameters: [
-        {
-          key.name: "first",
-          key.nameoffset: 1,
-          key.namelength: 14
-        },
-        {
-          key.name: "second",
-          key.nameoffset: 17,
-          key.namelength: 13
-        },
-        {
-          key.name: "third",
-          key.nameoffset: 32,
-          key.namelength: 10
-        }
-      ],
-      key.active_parameter: 0
-    },
-    {
-      key.name: "(arg1: Double, arg2: Float, arg3: Int) -> Double",
-      key.parameters: [
-        {
-          key.name: "param1",
-          key.nameoffset: 1,
-          key.namelength: 12
-        },
-        {
-          key.name: "arg2",
-          key.nameoffset: 15,
-          key.namelength: 11
-        },
-        {
-          key.name: "param3",
-          key.nameoffset: 28,
-          key.namelength: 9
-        }
-      ],
-      key.active_parameter: 0
-    },
-    {
-      key.name: "(numbers: Double...) -> Double",
-      key.parameters: [
-        {
-          key.name: "numbers",
-          key.nameoffset: 1,
-          key.namelength: 18
-        }
-      ],
-      key.active_parameter: 0
-    },
-    {
-      key.name: "(x: Int, y: Int, with: (Int, Int) throws -> Int) throws -> Int!",
-      key.parameters: [
-        {
-          key.name: "x",
-          key.nameoffset: 1,
-          key.namelength: 6
-        },
-        {
-          key.name: "y",
-          key.nameoffset: 9,
-          key.namelength: 6
-        },
-        {
-          key.name: "adder",
-          key.nameoffset: 17,
-          key.namelength: 30
-        }
-      ],
-      key.active_parameter: 0
-    },
-    {
-      key.name: "(x: Int) -> (Int) -> Int",
-      key.parameters: [
-        {
-          key.name: "x",
-          key.nameoffset: 1,
-          key.namelength: 6
-        }
-      ],
-      key.active_parameter: 0
-    }
-  ],
-  key.active_signature: 0
-}
diff --git a/test/SourceKit/SignatureHelp/signature_help_default_args.swift b/test/SourceKit/SignatureHelp/signature_help_default_args.swift
deleted file mode 100644
index 057fc4180f83f..0000000000000
--- a/test/SourceKit/SignatureHelp/signature_help_default_args.swift
+++ /dev/null
@@ -1,164 +0,0 @@
-// RUN: %empty-directory(%t)
-// RUN: split-file %s %t
-// RUN: %sourcekitd-test -req=signaturehelp -pos=23:5 %t/input.swift -- %t/input.swift > %t/actual.result
-// RUN: diff -u %t/expected.result %t/actual.result
-
-//--- input.swift
-func add(_ x: Int = 10, to y: Int) -> Int {}
-
-func add(oneTo x: inout Int) {}
-
-func add(_ x: Int, to y: Int? = nil) -> String {}
-
-func add(first: Double!, second: Float = .pi, third: Int) -> Double {}
-
-struct S {
-  let a: Bool
-}
-
-func add(s: S = S(a: false)) -> Double {}
-
-func add(x: Int, y: Int, with adder: (Int, Int) -> Int = { $0 + $1 }) -> Int {}
-
-let importantValue = 42
-
-func add(x: Int = importantValue) {}
-
-func add(x: Int, line: UInt = #line, file: StaticString = #file) {}
-
-add()
-
-//--- expected.result
-{
-  key.signatures: [
-    {
-      key.name: "add(_ x: Int = 10, to: Int) -> Int",
-      key.parameters: [
-        {
-          key.name: "x",
-          key.nameoffset: 4,
-          key.namelength: 13
-        },
-        {
-          key.name: "y",
-          key.nameoffset: 19,
-          key.namelength: 7
-        }
-      ],
-      key.active_parameter: 0
-    },
-    {
-      key.name: "add(oneTo: inout Int)",
-      key.parameters: [
-        {
-          key.name: "x",
-          key.nameoffset: 4,
-          key.namelength: 16
-        }
-      ],
-      key.active_parameter: 0
-    },
-    {
-      key.name: "add(_ x: Int, to: Int? = nil) -> String",
-      key.parameters: [
-        {
-          key.name: "x",
-          key.nameoffset: 4,
-          key.namelength: 8
-        },
-        {
-          key.name: "y",
-          key.nameoffset: 14,
-          key.namelength: 14
-        }
-      ],
-      key.active_parameter: 0
-    },
-    {
-      key.name: "add(first: Double!, second: Float = .pi, third: Int) -> Double",
-      key.parameters: [
-        {
-          key.name: "first",
-          key.nameoffset: 4,
-          key.namelength: 14
-        },
-        {
-          key.name: "second",
-          key.nameoffset: 20,
-          key.namelength: 19
-        },
-        {
-          key.name: "third",
-          key.nameoffset: 41,
-          key.namelength: 10
-        }
-      ],
-      key.active_parameter: 0
-    },
-    {
-      key.name: "add(s: S = S(a: false)) -> Double",
-      key.parameters: [
-        {
-          key.name: "s",
-          key.nameoffset: 4,
-          key.namelength: 18
-        }
-      ],
-      key.active_parameter: 0
-    },
-    {
-      key.name: "add(x: Int, y: Int, with: (Int, Int) -> Int = { $0 + $1 }) -> Int",
-      key.parameters: [
-        {
-          key.name: "x",
-          key.nameoffset: 4,
-          key.namelength: 6
-        },
-        {
-          key.name: "y",
-          key.nameoffset: 12,
-          key.namelength: 6
-        },
-        {
-          key.name: "adder",
-          key.nameoffset: 20,
-          key.namelength: 37
-        }
-      ],
-      key.active_parameter: 0
-    },
-    {
-      key.name: "add(x: Int = importantValue)",
-      key.parameters: [
-        {
-          key.name: "x",
-          key.nameoffset: 4,
-          key.namelength: 23
-        }
-      ],
-      key.active_parameter: 0
-    },
-    {
-      key.name: "add(x: Int, line: UInt = #line, file: StaticString = #file)",
-      key.parameters: [
-        {
-          key.name: "x",
-          key.nameoffset: 4,
-          key.namelength: 6
-        },
-        {
-          key.name: "line",
-          key.nameoffset: 12,
-          key.namelength: 18
-        },
-        {
-          key.name: "file",
-          key.nameoffset: 32,
-          key.namelength: 26
-        }
-      ],
-      key.active_parameter: 0
-    }
-  ],
-  key.active_signature: 0
-}
diff --git a/test/SourceKit/SignatureHelp/signature_help_doc.swift b/test/SourceKit/SignatureHelp/signature_help_doc.swift
deleted file mode 100644
index 171a226539d2f..0000000000000
--- a/test/SourceKit/SignatureHelp/signature_help_doc.swift
+++ /dev/null
@@ -1,47 +0,0 @@
-// RUN: %empty-directory(%t)
-// RUN: split-file %s %t
-// RUN: %sourcekitd-test -req=signaturehelp -pos=17:8 %t/input.swift -- %t/input.swift > %t/actual.result
-// RUN: diff -u %t/expected.result %t/actual.result
-
-//--- input.swift
-/// Adds two integers.
-///
-/// - Parameters:
-///   - x: The first integer to add.
-///   - y: The second integer to add.
-///
-/// Usage:
-/// ```swift
-/// add(1, to: 2) // 3
-/// ```
-///
-/// - Returns: The sum of the two integers.
-func add(_ x: Int, to y: Int) -> Int {
-  return x + y
-}
-
-add(x: )
-
-//--- expected.result
-{
-  key.signatures: [
-    {
-      key.name: "add(_ x: Int, to: Int) -> Int",
-      key.doc_comment: "Adds two integers.\n\n- Parameters:\n  - x: The first integer to add.\n  - y: The second integer to add.\n\nUsage:\n```swift\nadd(1, to: 2) // 3\n```\n\n- Returns: The sum of the two integers.",
-      key.parameters: [
-        {
-          key.name: "x",
-          key.nameoffset: 4,
-          key.namelength: 8
-        },
-        {
-          key.name: "y",
-          key.nameoffset: 14,
-          key.namelength: 7
-        }
-      ],
-      key.active_parameter: 0
-    }
-  ],
-  key.active_signature: 0
-}
diff --git a/test/SourceKit/SignatureHelp/signature_help_enum_case.swift b/test/SourceKit/SignatureHelp/signature_help_enum_case.swift
deleted file mode 100644
index b1edb3e5cd60c..0000000000000
--- a/test/SourceKit/SignatureHelp/signature_help_enum_case.swift
+++ /dev/null
@@ -1,69 +0,0 @@
-// RUN: %empty-directory(%t)
-// RUN: split-file %s %t
-// RUN: %sourcekitd-test -req=signaturehelp -pos=7:15 %t/input.swift -- %t/input.swift > %t/actual_labelled.result
-// RUN: diff -u %t/expected_labelled.result %t/actual_labelled.result
-// RUN: %sourcekitd-test -req=signaturehelp -pos=11:18 %t/input.swift -- %t/input.swift > %t/actual_unlabelled.result
-// RUN: diff -u %t/expected_unlabelled.result %t/actual_unlabelled.result
-
-//--- input.swift
-enum Barcode {
-  case upc(numberSystem: Int, manufacturer: Int, product: Int, check: Int)
-  case qrCode(String)
-}
-
-func testLabeled() {
-  Barcode.upc(, manufacturer: 85909, product: 51226, check: 3)
-}
-
-func testUnlabled() {
-  Barcode.qrCode()
-}
-
-//--- expected_labelled.result
-{
-  key.signatures: [
-    {
-      key.name: "upc(numberSystem: Int, manufacturer: Int, product: Int, check: Int) -> Barcode",
-      key.parameters: [
-        {
-          key.name: "numberSystem",
-          key.nameoffset: 4,
-          key.namelength: 17
-        },
-        {
-          key.name: "manufacturer",
-          key.nameoffset: 23,
-          key.namelength: 17
-        },
-        {
-          key.name: "product",
-          key.nameoffset: 42,
-          key.namelength: 12
-        },
-        {
-          key.name: "check",
-          key.nameoffset: 56,
-          key.namelength: 10
-        }
-      ],
-      key.active_parameter: 0
-    }
-  ],
-  key.active_signature: 0
-}
-//--- expected_unlabelled.result
-{
-  key.signatures: [
-    {
-      key.name: "qrCode(String) -> Barcode",
-      key.parameters: [
-        {
-          key.nameoffset: 7,
-          key.namelength: 6
-        }
-      ],
-      key.active_parameter: 0
-    }
-  ],
-  key.active_signature: 0
-}
diff --git a/test/SourceKit/SignatureHelp/signature_help_init.swift b/test/SourceKit/SignatureHelp/signature_help_init.swift
deleted file mode 100644
index 24528437173cb..0000000000000
--- a/test/SourceKit/SignatureHelp/signature_help_init.swift
+++ /dev/null
@@ -1,39 +0,0 @@
-// RUN: %empty-directory(%t)
-// RUN: split-file %s %t
-// RUN: %sourcekitd-test -req=signaturehelp -pos=5:27 %t/input.swift -- %t/input.swift > %t/actual.result
-// RUN: diff -u %t/expected.result %t/actual.result
-
-//--- input.swift
-struct Person {
-  init(name: String, age: Int, profession job: String) { }
-}
-
-Person(name: "John", age: )
-
-//--- expected.result
-{
-  key.signatures: [
-    {
-      key.name: "init(name: String, age: Int, profession: String)",
-      key.parameters: [
-        {
-          key.name: "name",
-          key.nameoffset: 5,
-          key.namelength: 12
-        },
-        {
-          key.name: "age",
-          key.nameoffset: 19,
-          key.namelength: 8
-        },
-        {
-          key.name: "job",
-          key.nameoffset: 29,
-          key.namelength: 18
-        }
-      ],
-      key.active_parameter: 1
-    }
-  ],
-  key.active_signature: 0
-}
diff --git a/test/SourceKit/SignatureHelp/signature_help_member_closure.swift b/test/SourceKit/SignatureHelp/signature_help_member_closure.swift
deleted file mode 100644
index e71d7afc30c31..0000000000000
--- a/test/SourceKit/SignatureHelp/signature_help_member_closure.swift
+++ /dev/null
@@ -1,38 +0,0 @@
-// RUN: %empty-directory(%t)
-// RUN: split-file %s %t
-// RUN: %sourcekitd-test -req=signaturehelp -pos=5:23 %t/input.swift -- %t/input.swift > %t/actual.result
-// RUN: diff -u %t/expected.result %t/actual.result
-
-//--- input.swift
-struct Observable {
-  var observer: (String, Int?, [AnyHashable: [Double?]]) async throws -> [Observable?]
-  
-  func notify() async throws {
-    observer("EVENT", , [:])
-  }
-}
-
-//--- expected.result
-{
-  key.signatures: [
-    {
-      key.name: "observer(String, Int?, [AnyHashable : [Double?]]) async throws -> [Observable?]",
-      key.parameters: [
-        {
-          key.nameoffset: 9,
-          key.namelength: 6
-        },
-        {
-          key.nameoffset: 17,
-          key.namelength: 4
-        },
-        {
-          key.nameoffset: 23,
-          key.namelength: 25
-        }
-      ],
-      key.active_parameter: 1
-    }
-  ],
-  key.active_signature: 0
-}
diff --git a/test/SourceKit/SignatureHelp/signature_help_member_func.swift b/test/SourceKit/SignatureHelp/signature_help_member_func.swift
deleted file mode 100644
index c1a4f921fe61f..0000000000000
--- a/test/SourceKit/SignatureHelp/signature_help_member_func.swift
+++ /dev/null
@@ -1,177 +0,0 @@
-// RUN: %empty-directory(%t)
-// RUN: split-file %s %t
-// RUN: %sourcekitd-test -req=signaturehelp -pos=36:11 %t/input.swift -- %t/input.swift > %t/actual.result
-// RUN: diff -u %t/expected.result %t/actual.result
-
-//--- input.swift
-struct Adder {
-  func add(_ x: Int, to y: Int) -> Int {
-    return x + y
-  }
-  
-  func add(oneTo x: inout Int) {
-    x += 1
-  }
-  
-  func add<T: AdditiveArithmetic>(_ x: T, to y: T) -> T {
-    return x + y
-  }
-  
-  func add(first: Double!, second: Float, third: Int) -> Double {
-    return first + Double(second) + Double(third)
-  }
-  
-  func add(arg1 param1: Double, arg2: Float, arg3 param3: Int) -> Double {
-    return param1 + Double(arg2) + Double(param3)
-  }
-  
-  func add(numbers: Double...) -> Double {
-    return numbers.reduce(into: 0) { $0 += $1 }
-  }
-  
-  func add(x: Int, y: Int, with adder: (Int, Int) -> Int) -> Int {
-    return adder(x, y)
-  }
-  
-  func add(x: Int) -> (Int) -> Int {
-    return { (y: Int) in x + y }
-  }
-}
-
-let adder = Adder()
-adder.add()
-
-//--- expected.result
-{
-  key.signatures: [
-    {
-      key.name: "add(_ x: Int, to: Int) -> Int",
-      key.parameters: [
-        {
-          key.name: "x",
-          key.nameoffset: 4,
-          key.namelength: 8
-        },
-        {
-          key.name: "y",
-          key.nameoffset: 14,
-          key.namelength: 7
-        }
-      ],
-      key.active_parameter: 0
-    },
-    {
-      key.name: "add(oneTo: inout Int)",
-      key.parameters: [
-        {
-          key.name: "x",
-          key.nameoffset: 4,
-          key.namelength: 16
-        }
-      ],
-      key.active_parameter: 0
-    },
-    {
-      key.name: "add(_ x: AdditiveArithmetic, to: AdditiveArithmetic) -> AdditiveArithmetic",
-      key.parameters: [
-        {
-          key.name: "x",
-          key.nameoffset: 4,
-          key.namelength: 23
-        },
-        {
-          key.name: "y",
-          key.nameoffset: 29,
-          key.namelength: 22
-        }
-      ],
-      key.active_parameter: 0
-    },
-    {
-      key.name: "add(first: Double!, second: Float, third: Int) -> Double",
-      key.parameters: [
-        {
-          key.name: "first",
-          key.nameoffset: 4,
-          key.namelength: 14
-        },
-        {
-          key.name: "second",
-          key.nameoffset: 20,
-          key.namelength: 13
-        },
-        {
-          key.name: "third",
-          key.nameoffset: 35,
-          key.namelength: 10
-        }
-      ],
-      key.active_parameter: 0
-    },
-    {
-      key.name: "add(arg1: Double, arg2: Float, arg3: Int) -> Double",
-      key.parameters: [
-        {
-          key.name: "param1",
-          key.nameoffset: 4,
-          key.namelength: 12
-        },
-        {
-          key.name: "arg2",
-          key.nameoffset: 18,
-          key.namelength: 11
-        },
-        {
-          key.name: "param3",
-          key.nameoffset: 31,
-          key.namelength: 9
-        }
-      ],
-      key.active_parameter: 0
-    },
-    {
-      key.name: "add(numbers: Double...) -> Double",
-      key.parameters: [
-        {
-          key.name: "numbers",
-          key.nameoffset: 4,
-          key.namelength: 18
-        }
-      ],
-      key.active_parameter: 0
-    },
-    {
-      key.name: "add(x: Int, y: Int, with: (Int, Int) -> Int) -> Int",
-      key.parameters: [
-        {
-          key.name: "x",
-          key.nameoffset: 4,
-          key.namelength: 6
-        },
-        {
-          key.name: "y",
-          key.nameoffset: 12,
-          key.namelength: 6
-        },
-        {
-          key.name: "adder",
-          key.nameoffset: 20,
-          key.namelength: 23
-        }
-      ],
-      key.active_parameter: 0
-    },
-    {
-      key.name: "add(x: Int) -> (Int) -> Int",
-      key.parameters: [
-        {
-          key.name: "x",
-          key.nameoffset: 4,
-          key.namelength: 6
-        }
-      ],
-      key.active_parameter: 0
-    }
-  ],
-  key.active_signature: 0
-}
diff --git a/test/SourceKit/SignatureHelp/signature_help_member_generic.swift b/test/SourceKit/SignatureHelp/signature_help_member_generic.swift
deleted file mode 100644
index 732703439a6b1..0000000000000
--- a/test/SourceKit/SignatureHelp/signature_help_member_generic.swift
+++ /dev/null
@@ -1,32 +0,0 @@
-// RUN: %empty-directory(%t)
-// RUN: split-file %s %t
-// RUN: %sourcekitd-test -req=signaturehelp -pos=8:15 %t/input.swift -- %t/input.swift > %t/actual.result
-// RUN: diff -u %t/expected.result %t/actual.result
-
-//--- input.swift
-struct Vector<Value> {
-  init(elements: [Value]) { }
-  
-  func dot(with other: Vector<Value>) -> Value { }
-}
-
-let vec = Vector(elements: [1.0, 2.1, 3.4])
-vec.dot(with: )
-
-//--- expected.result
-{
-  key.signatures: [
-    {
-      key.name: "dot(with: Vector<Double>) -> Double",
-      key.parameters: [
-        {
-          key.name: "other",
-          key.nameoffset: 4,
-          key.namelength: 20
-        }
-      ],
-      key.active_parameter: 0
-    }
-  ],
-  key.active_signature: 0
-}
diff --git a/test/SourceKit/SignatureHelp/signature_help_member_subscript.swift b/test/SourceKit/SignatureHelp/signature_help_member_subscript.swift
deleted file mode 100644
index 20ce499672d61..0000000000000
--- a/test/SourceKit/SignatureHelp/signature_help_member_subscript.swift
+++ /dev/null
@@ -1,77 +0,0 @@
-// RUN: %empty-directory(%t)
-// RUN: split-file %s %t
-// RUN: %sourcekitd-test -req=signaturehelp -pos=16:8 %t/input.swift -- %t/input.swift > %t/actual.result
-// RUN: diff -u %t/expected.result %t/actual.result
-
-//--- input.swift
-struct Matrix {
-  subscript(row: Int, column: Int) -> Int {
-    return 0
-  }
-  
-  subscript(row r: Int) -> [Int] {
-    return []
-  }
-  
-  subscript(column c: Int) -> [Int] {
-    return []
-  }
-}
-
-let matrix = Matrix()
-matrix[]
-
-//--- expected.result
-{
-  key.signatures: [
-    {
-      key.name: "subscript(keyPath: KeyPath<Matrix, Value>) -> Value",
-      key.parameters: [
-        {
-          key.nameoffset: 10,
-          key.namelength: 31
-        }
-      ],
-      key.active_parameter: 0
-    },
-    {
-      key.name: "subscript(row: Int, column: Int) -> Int",
-      key.parameters: [
-        {
-          key.name: "row",
-          key.nameoffset: 10,
-          key.namelength: 8
-        },
-        {
-          key.name: "column",
-          key.nameoffset: 20,
-          key.namelength: 11
-        }
-      ],
-      key.active_parameter: 0
-    },
-    {
-      key.name: "subscript(row: Int) -> [Int]",
-      key.parameters: [
-        {
-          key.name: "r",
-          key.nameoffset: 10,
-          key.namelength: 8
-        }
-      ],
-      key.active_parameter: 0
-    },
-    {
-      key.name: "subscript(column: Int) -> [Int]",
-      key.parameters: [
-        {
-          key.name: "c",
-          key.nameoffset: 10,
-          key.namelength: 11
-        }
-      ],
-      key.active_parameter: 0
-    }
-  ],
-  key.active_signature: 0
-}
diff --git a/test/SourceKit/SignatureHelp/signature_help_raw_identifier.swift b/test/SourceKit/SignatureHelp/signature_help_raw_identifier.swift
deleted file mode 100644
index 7b3e40fa7fcb1..0000000000000
--- a/test/SourceKit/SignatureHelp/signature_help_raw_identifier.swift
+++ /dev/null
@@ -1,29 +0,0 @@
-// RUN: %empty-directory(%t)
-// RUN: split-file %s %t
-// RUN: %sourcekitd-test -req=signaturehelp -pos=5:37 %t/input.swift -- %t/input.swift > %t/actual.result
-// RUN: diff -u %t/expected.result %t/actual.result
-
-//--- input.swift
-struct `Raw Identifier` {
-  func `some method :)`(`argument label!` `param label?`: Int) {}
-}
-
-`Raw Identifier`().`some method :)`()
-
-//--- expected.result
-{
-  key.signatures: [
-    {
-      key.name: "`some method :)`(`argument label!`: Int)",
-      key.parameters: [
-        {
-          key.name: "param label?",
-          key.nameoffset: 17,
-          key.namelength: 22
-        }
-      ],
-      key.active_parameter: 0
-    }
-  ],
-  key.active_signature: 0
-}
diff --git a/test/SourceKit/SignatureHelp/signature_help_top_level.swift b/test/SourceKit/SignatureHelp/signature_help_top_level.swift
deleted file mode 100644
index 0aa5f2a89372a..0000000000000
--- a/test/SourceKit/SignatureHelp/signature_help_top_level.swift
+++ /dev/null
@@ -1,174 +0,0 @@
-// RUN: %empty-directory(%t)
-// RUN: split-file %s %t
-// RUN: %sourcekitd-test -req=signaturehelp -pos=33:5 %t/input.swift -- %t/input.swift > %t/actual.result
-// RUN: diff -u %t/expected.result %t/actual.result
-
-//--- input.swift
-func add(_ x: Int, to y: Int) -> Int {
-  return x + y
-}
-
-func add(oneTo x: inout Int) {
-  x += 1
-}
-
-func add<T: AdditiveArithmetic>(_ x: T, to y: T) -> T {
-  return x + y
-}
-
-func add(first: Double!, second: Float, third: Int) -> Double {
-  return first + Double(second) + Double(third)
-}
-
-func add(arg1 param1: Double, arg2: Float, arg3 param3: Int) -> Double {
-  return param1 + Double(arg2) + Double(param3)
-}
-
-func add(numbers: Double...) -> Double {
-  return numbers.reduce(into: 0) { $0 += $1 }
-}
-
-func add(x: Int, y: Int, with adder: (Int, Int) -> Int) -> Int {
-  return adder(x, y)
-}
-
-func add(x: Int) -> (Int) -> Int {
-  return { (y: Int) in x + y }
-}
-
-add()
-
-//--- expected.result
-{
-  key.signatures: [
-    {
-      key.name: "add(_ x: Int, to: Int) -> Int",
-      key.parameters: [
-        {
-          key.name: "x",
-          key.nameoffset: 4,
-          key.namelength: 8
-        },
-        {
-          key.name: "y",
-          key.nameoffset: 14,
-          key.namelength: 7
-        }
-      ],
-      key.active_parameter: 0
-    },
-    {
-      key.name: "add(oneTo: inout Int)",
-      key.parameters: [
-        {
-          key.name: "x",
-          key.nameoffset: 4,
-          key.namelength: 16
-        }
-      ],
-      key.active_parameter: 0
-    },
-    {
-      key.name: "add(_ x: AdditiveArithmetic, to: AdditiveArithmetic) -> AdditiveArithmetic",
-      key.parameters: [
-        {
-          key.name: "x",
-          key.nameoffset: 4,
-          key.namelength: 23
-        },
-        {
-          key.name: "y",
-          key.nameoffset: 29,
-          key.namelength: 22
-        }
-      ],
-      key.active_parameter: 0
-    },
-    {
-      key.name: "add(first: Double!, second: Float, third: Int) -> Double",
-      key.parameters: [
-        {
-          key.name: "first",
-          key.nameoffset: 4,
-          key.namelength: 14
-        },
-        {
-          key.name: "second",
-          key.nameoffset: 20,
-          key.namelength: 13
-        },
-        {
-          key.name: "third",
-          key.nameoffset: 35,
-          key.namelength: 10
-        }
-      ],
-      key.active_parameter: 0
-    },
-    {
-      key.name: "add(arg1: Double, arg2: Float, arg3: Int) -> Double",
-      key.parameters: [
-        {
-          key.name: "param1",
-          key.nameoffset: 4,
-          key.namelength: 12
-        },
-        {
-          key.name: "arg2",
-          key.nameoffset: 18,
-          key.namelength: 11
-        },
-        {
-          key.name: "param3",
-          key.nameoffset: 31,
-          key.namelength: 9
-        }
-      ],
-      key.active_parameter: 0
-    },
-    {
-      key.name: "add(numbers: Double...) -> Double",
-      key.parameters: [
-        {
-          key.name: "numbers",
-          key.nameoffset: 4,
-          key.namelength: 18
-        }
-      ],
-      key.active_parameter: 0
-    },
-    {
-      key.name: "add(x: Int, y: Int, with: (Int, Int) -> Int) -> Int",
-      key.parameters: [
-        {
-          key.name: "x",
-          key.nameoffset: 4,
-          key.namelength: 6
-        },
-        {
-          key.name: "y",
-          key.nameoffset: 12,
-          key.namelength: 6
-        },
-        {
-          key.name: "adder",
-          key.nameoffset: 20,
-          key.namelength: 23
-        }
-      ],
-      key.active_parameter: 0
-    },
-    {
-      key.name: "add(x: Int) -> (Int) -> Int",
-      key.parameters: [
-        {
-          key.name: "x",
-          key.nameoffset: 4,
-          key.namelength: 6
-        }
-      ],
-      key.active_parameter: 0
-    }
-  ],
-  key.active_signature: 0
-}
diff --git a/test/SourceKit/SignatureHelp/signature_help_top_level_generic.swift b/test/SourceKit/SignatureHelp/signature_help_top_level_generic.swift
deleted file mode 100644
index 2a3e58bda7fa2..0000000000000
--- a/test/SourceKit/SignatureHelp/signature_help_top_level_generic.swift
+++ /dev/null
@@ -1,39 +0,0 @@
-// RUN: %empty-directory(%t)
-// RUN: split-file %s %t
-// RUN: %sourcekitd-test -req=signaturehelp -pos=5:27 %t/input.swift -- %t/input.swift > %t/actual.result
-// RUN: diff -u %t/expected.result %t/actual.result
-
-//--- input.swift
-func add<T>(x: T, y: T, with adder: (T, T) -> T) -> T where T: AdditiveArithmetic {
-  return adder(x, y)
-}
-
-add(x: "A", y: "B", with: )
-
-//--- expected.result
-{
-  key.signatures: [
-    {
-      key.name: "add(x: String, y: String, with: (String, String) -> String) -> String",
-      key.parameters: [
-        {
-          key.name: "x",
-          key.nameoffset: 4,
-          key.namelength: 9
-        },
-        {
-          key.name: "y",
-          key.nameoffset: 15,
-          key.namelength: 9
-        },
-        {
-          key.name: "adder",
-          key.nameoffset: 26,
-          key.namelength: 32
-        }
-      ],
-      key.active_parameter: 2
-    }
-  ],
-  key.active_signature: 0
-}
diff --git a/tools/SourceKit/include/SourceKit/Core/LangSupport.h b/tools/SourceKit/include/SourceKit/Core/LangSupport.h
index 9daf7a85afe8b..d60a7f6cd979d 100644
--- a/tools/SourceKit/include/SourceKit/Core/LangSupport.h
+++ b/tools/SourceKit/include/SourceKit/Core/LangSupport.h
@@ -35,6 +35,12 @@ namespace llvm {
   class MemoryBuffer;
 }
 
+namespace swift {
+namespace ide {
+struct FormattedSignatureHelp;
+} // namespace ide
+} // namespace swift
+
 namespace SourceKit {
 class GlobalConfig;
 using swift::ide::CancellableResult;
@@ -1012,51 +1018,14 @@ class ConformingMethodListConsumer {
   virtual void cancelled() = 0;
 };
 
-struct SignatureHelpResponse {
-  struct Parameter {
-    /// The offset of the parameter text in the signature text.
-    unsigned Offset;
-
-    /// The length of the parameter text in the signature text.
-    unsigned Length;
-
-    /// The documentation comment for the parameter.
-    StringRef DocComment;
-
-    /// The internal parameter name.
-    StringRef Name;
-
-    Parameter() {}
-  };
-
-  struct Signature {
-    /// The text describing the signature.
-    StringRef Text;
-
-    /// The documentation comment for the signature.
-    StringRef Doc;
-
-    /// The index of the active parameter if any.
-    std::optional<unsigned> ActiveParam;
-
-    /// The parameters for the signature.
-    ArrayRef<Parameter> Params;
-  };
-
-  /// The index of the active signature.
-  unsigned ActiveSignature;
-
-  /// The available signatures/overloads.
-  ArrayRef<Signature> Signatures;
-};
-
 class SignatureHelpConsumer {
   virtual void anchor();
 
 public:
   virtual ~SignatureHelpConsumer() {}
 
-  virtual void handleResult(const SignatureHelpResponse &Result) = 0;
+  virtual void
+  handleResult(const swift::ide::FormattedSignatureHelp &Result) = 0;
   virtual void setReusingASTContext(bool flag) = 0;
   virtual void failed(StringRef ErrDescription) = 0;
   virtual void cancelled() = 0;
diff --git a/tools/SourceKit/lib/SwiftLang/SwiftSignatureHelp.cpp b/tools/SourceKit/lib/SwiftLang/SwiftSignatureHelp.cpp
index 7ea8dc1852c1a..2b5ddb53a5169 100644
--- a/tools/SourceKit/lib/SwiftLang/SwiftSignatureHelp.cpp
+++ b/tools/SourceKit/lib/SwiftLang/SwiftSignatureHelp.cpp
@@ -12,193 +12,14 @@
 
 #include "SwiftASTManager.h"
 #include "SwiftLangSupport.h"
-#include "swift/AST/Decl.h"
-#include "swift/AST/Types.h"
-#include "swift/IDE/CodeCompletionResultPrinter.h"
-#include "swift/IDE/CodeCompletionStringBuilder.h"
-#include "swift/IDE/CommentConversion.h"
 #include "swift/IDE/SignatureHelp.h"
+#include "swift/IDE/SignatureHelpFormatter.h"
 #include "swift/IDETool/IDEInspectionInstance.h"
-#include "llvm/Support/Allocator.h"
-#include "llvm/Support/raw_ostream.h"
 
 using namespace SourceKit;
 using namespace swift;
 using namespace ide;
 
-using ChunkKind = CodeCompletionString::Chunk::ChunkKind;
-
-namespace {
-struct SignatureInfo {
-  StringRef Text;
-  StringRef DocComment;
-  std::optional<unsigned> ActiveParam;
-  SmallVector<SourceKit::SignatureHelpResponse::Parameter, 1> Params;
-
-  SignatureInfo() {}
-};
-} // namespace
-
-/// \returns Array of parameters of \p VD accounting for implicitly curried
-/// instance methods.
-static ArrayRef<const ParamDecl *>
-getParameterArray(const ValueDecl *VD, bool IsImplicitlyCurried,
-                  const ParamDecl *&Scratch) {
-  if (!VD)
-    return {};
-
-  if (IsImplicitlyCurried) {
-    auto *FD = dyn_cast<AbstractFunctionDecl>(VD);
-    assert(FD && FD->hasImplicitSelfDecl());
-
-    Scratch = FD->getImplicitSelfDecl();
-    return ArrayRef(&Scratch, 1);
-  }
-
-  if (auto *ParamList = VD->getParameterList())
-    return ParamList->getArray();
-
-  return {};
-}
-
-static CodeCompletionString *createSignatureString(
-    llvm::BumpPtrAllocator &Allocator, ValueDecl *FD, AnyFunctionType *AFT,
-    const DeclContext *DC, GenericSignature GenericSig, bool IsSubscript,
-    bool IsMember, bool IsImplicitlyCurried, bool IsSecondApply) {
-  CodeCompletionStringBuilder StringBuilder(
-      Allocator, /*AnnotateResults=*/false,
-      /*UnderscoreEmptyArgumentLabel=*/!IsSubscript,
-      /*FullParameterFlags=*/true);
-
-  DeclBaseName BaseName;
-
-  if (!IsSecondApply && FD) {
-    BaseName = FD->getBaseName();
-  } else if (IsSubscript) {
-    BaseName = DeclBaseName::createSubscript();
-  }
-
-  if (!BaseName.empty())
-    StringBuilder.addValueBaseName(BaseName, IsMember);
-
-  StringBuilder.addLeftParen();
-
-  const ParamDecl *ParamScratch;
-  StringBuilder.addCallArgumentPatterns(
-      AFT->getParams(),
-      getParameterArray(FD, IsImplicitlyCurried, ParamScratch), DC, GenericSig,
-      DefaultArgumentOutputMode::All, /*includeDefaultValues=*/true);
-
-  StringBuilder.addRightParen();
-
-  if (!IsImplicitlyCurried) {
-    // For a second apply, we don't pass the declaration to avoid adding
-    // incorrect rethrows and reasync which are only usable in a single apply.
-    StringBuilder.addEffectsSpecifiers(
-        AFT,
-        /*AFD=*/IsSecondApply ? nullptr
-                              : dyn_cast_or_null<AbstractFunctionDecl>(FD));
-  }
-
-  if (FD && FD->isImplicitlyUnwrappedOptional()) {
-    StringBuilder.addTypeAnnotationForImplicitlyUnwrappedOptional(
-        AFT->getResult(), DC, GenericSig);
-  } else {
-    StringBuilder.addTypeAnnotation(AFT->getResult(), DC, GenericSig);
-  }
-
-  return StringBuilder.createCompletionString();
-}
-
-static StringRef copyAndClearString(llvm::BumpPtrAllocator &Allocator,
-                                    SmallVectorImpl<char> &Str) {
-  auto Ref = StringRef(Str.data(), Str.size()).copy(Allocator);
-  Str.clear();
-  return Ref;
-}
-
-static void getSignatureInfo(const DeclContext *DC, const Signature &Sig,
-                             SignatureInfo &Info,
-                             llvm::BumpPtrAllocator &Allocator) {
-  auto *FD = Sig.FuncD;
-  auto *AFT = Sig.FuncTy;
-
-  bool IsConstructor = false;
-  GenericSignature genericSig;
-  if (FD) {
-    IsConstructor = isa<ConstructorDecl>(FD);
-
-    if (auto *GC = FD->getAsGenericContext())
-      genericSig = GC->getGenericSignature();
-  }
-
-  auto *SignatureString =
-      createSignatureString(Allocator, FD, AFT, DC, genericSig, Sig.IsSubscript,
-                            /*IsMember=*/bool(Sig.BaseType),
-                            Sig.IsImplicitlyCurried, Sig.IsSecondApply);
-
-  llvm::SmallString<512> SS;
-  llvm::raw_svector_ostream OS(SS);
-
-  bool SkipResult = AFT->getResult()->isVoid() || IsConstructor;
-
-  auto Chunks = SignatureString->getChunks();
-  auto C = Chunks.begin();
-  while (C != Chunks.end()) {
-    if (C->is(ChunkKind::TypeAnnotation) && SkipResult) {
-      ++C;
-      continue;
-    }
-
-    if (C->is(ChunkKind::TypeAnnotation))
-      OS << " -> ";
-
-    if (C->is(ChunkKind::CallArgumentBegin)) {
-      unsigned NestingLevel = C->getNestingLevel();
-      ++C;
-
-      auto &P = Info.Params.emplace_back();
-      P.Offset = SS.size();
-
-      do {
-        if (!C->is(ChunkKind::CallArgumentClosureType) && C->hasText())
-          OS << C->getText();
-
-        ++C;
-      } while (C != Chunks.end() && !C->endsPreviousNestedGroup(NestingLevel));
-
-      P.Length = SS.size() - P.Offset;
-      continue;
-    }
-
-    if (C->hasText())
-      OS << C->getText();
-
-    ++C;
-  }
-
-  Info.Text = copyAndClearString(Allocator, SS);
-  Info.ActiveParam = Sig.ParamIdx;
-
-  // Parameter names.
-  const ParamDecl *ParamScratch;
-  auto ParamDecls =
-      getParameterArray(FD, Sig.IsImplicitlyCurried, ParamScratch);
-
-  if (!ParamDecls.empty()) {
-    for (unsigned i = 0; i < Info.Params.size(); ++i) {
-      Info.Params[i].Name = ParamDecls[i]->getParameterName().str();
-    }
-  }
-
-  // Documentation.
-  if (FD) {
-    ide::getRawDocumentationComment(FD, OS);
-
-    Info.DocComment = copyAndClearString(Allocator, SS);
-  }
-}
-
 static void deliverResults(SourceKit::SignatureHelpConsumer &SKConsumer,
                            CancellableResult<SignatureHelpResults> Result) {
   switch (Result.getKind()) {
@@ -212,29 +33,9 @@ static void deliverResults(SourceKit::SignatureHelpConsumer &SKConsumer,
     }
 
     llvm::BumpPtrAllocator Allocator;
-    SmallVector<SignatureInfo, 4> Infos;
-
-    for (auto &Sig : Result->Result->Signatures) {
-      Infos.emplace_back();
-      auto &Info = Infos.back();
-
-      getSignatureInfo(Result->Result->DC, Sig, Info, Allocator);
-    }
-
-    SourceKit::SignatureHelpResponse SKResult;
-    SmallVector<SourceKit::SignatureHelpResponse::Signature, 8> SKSignatures;
-
-    for (auto &Info : Infos) {
-      SKSignatures.push_back(
-          {Info.Text, Info.DocComment, Info.ActiveParam, Info.Params});
-    }
-
-    SKResult.Signatures = SKSignatures;
-
-    // TODO(a7medev): Select active signature and param.
-    SKResult.ActiveSignature = 0;
+    SignatureHelpFormatter Formatter(Allocator);
 
-    SKConsumer.handleResult(SKResult);
+    SKConsumer.handleResult(Formatter.format(*Result->Result));
     break;
   }
   case CancellableResultKind::Failure:
diff --git a/tools/SourceKit/tools/sourcekitd/lib/Service/Requests.cpp b/tools/SourceKit/tools/sourcekitd/lib/Service/Requests.cpp
index 216b78d9e7e3a..3138558df83d9 100644
--- a/tools/SourceKit/tools/sourcekitd/lib/Service/Requests.cpp
+++ b/tools/SourceKit/tools/sourcekitd/lib/Service/Requests.cpp
@@ -36,6 +36,7 @@
 #include "swift/Basic/LLVMInitialize.h"
 #include "swift/Basic/Statistic.h"
 #include "swift/Basic/Version.h"
+#include "swift/IDE/SignatureHelpFormatter.h"
 
 #include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/IntrusiveRefCntPtr.h"
@@ -3645,7 +3646,8 @@ signatureHelp(StringRef PrimaryFilePath, int64_t Offset,
   public:
     Consumer(ResponseBuilder Builder) : SKResult(Builder.getDictionary()) {}
 
-    void handleResult(const SignatureHelpResponse &Result) override {
+    void
+    handleResult(const swift::ide::FormattedSignatureHelp &Result) override {
       SKResult.set(KeyActiveSignature, Result.ActiveSignature);
 
       auto Signatures = SKResult.setArray(KeySignatures);
@@ -3658,8 +3660,8 @@ signatureHelp(StringRef PrimaryFilePath, int64_t Offset,
         if (auto ActiveParam = Signature.ActiveParam)
           SignatureElem.set(KeyActiveParameter, ActiveParam.value());
 
-        if (!Signature.Doc.empty())
-          SignatureElem.set(KeyDocComment, Signature.Doc);
+        if (!Signature.DocComment.empty())
+          SignatureElem.set(KeyDocComment, Signature.DocComment);
 
         auto Params = SignatureElem.setArray(KeyParameters);
 
@@ -3671,9 +3673,6 @@ signatureHelp(StringRef PrimaryFilePath, int64_t Offset,
 
           ParamElem.set(KeyNameOffset, Param.Offset);
           ParamElem.set(KeyNameLength, Param.Length);
-
-          if (!Param.DocComment.empty())
-            ParamElem.set(KeyDocComment, Param.DocComment);
         }
       }
     }
diff --git a/tools/swift-ide-test/swift-ide-test.cpp b/tools/swift-ide-test/swift-ide-test.cpp
index a629fe5b1a429..19f5a49fb30f4 100644
--- a/tools/swift-ide-test/swift-ide-test.cpp
+++ b/tools/swift-ide-test/swift-ide-test.cpp
@@ -43,6 +43,8 @@
 #include "swift/IDE/IDERequests.h"
 #include "swift/IDE/ModuleInterfacePrinting.h"
 #include "swift/IDE/REPLCodeCompletion.h"
+#include "swift/IDE/SignatureHelp.h"
+#include "swift/IDE/SignatureHelpFormatter.h"
 #include "swift/IDE/SourceEntityWalker.h"
 #include "swift/IDE/SyntaxModel.h"
 #include "swift/IDE/TypeContextInfo.h"
@@ -117,6 +119,7 @@ enum class ActionType {
   Range,
   TypeContextInfo,
   ConformingMethodList,
+  SignatureHelp,
 };
 
 class NullDebuggerClient : public DebuggerClient {
@@ -251,7 +254,9 @@ Action(llvm::cl::desc("Mode:"), llvm::cl::init(ActionType::None),
                       "Print types for all expressions in the file"),
            clEnumValN(ActionType::ConformingMethodList,
 	                    "conforming-methods",
-                      "Perform conforming method analysis for expression")));
+                      "Perform conforming method analysis for expression"),
+           clEnumValN(ActionType::SignatureHelp, "signature-help",
+                      "Perform signature help")));
 
 static llvm::cl::opt<std::string>
 SourceFilename("source-filename", llvm::cl::desc("Name of the source file"),
@@ -1446,6 +1451,99 @@ printCodeCompletionLookedupTypeNames(ArrayRef<NullTerminatedStringRef> names,
   OS << "]\n";
 }
 
+static void printWithEscaping(StringRef Str, llvm::raw_ostream &OS) {
+  for (char C : Str) {
+    switch (C) {
+    case '\n':
+      OS << "\\n";
+      break;
+    case '\r':
+      OS << "\\r";
+      break;
+    case '\t':
+      OS << "\\t";
+      break;
+    case '\v':
+      OS << "\\v";
+      break;
+    case '\f':
+      OS << "\\f";
+      break;
+    default:
+      OS << C;
+      break;
+    }
+  }
+}
+
+static void printSignatureHelpResultsImpl(const FormattedSignatureHelp &Result,
+                                          llvm::raw_ostream &OS) {
+  OS << "Begin signatures, " << Result.Signatures.size() << " items\n";
+
+  for (unsigned i = 0; i < Result.Signatures.size(); ++i) {
+    const auto &Signature = Result.Signatures[i];
+    if (i == Result.ActiveSignature) {
+      OS << "Signature[Active]: ";
+    } else {
+      OS << "Signature: ";
+    }
+
+    StringRef signatureText = Signature.Text;
+
+    unsigned currentPos = 0;
+    for (unsigned j = 0; j < Signature.Params.size(); ++j) {
+      const auto &Param = Signature.Params[j];
+
+      if (Param.Offset > currentPos) {
+        OS << signatureText.substr(currentPos, Param.Offset - currentPos);
+      }
+
+      OS << "<param";
+      if (!Param.Name.empty()) {
+        OS << " name=\"" << Param.Name << '"';
+      }
+      if (Signature.ActiveParam && *Signature.ActiveParam == j) {
+        OS << " active";
+      }
+      OS << ">";
+      OS << signatureText.substr(Param.Offset, Param.Length);
+      OS << "</param>";
+
+      currentPos = Param.Offset + Param.Length;
+    }
+
+    if (currentPos < signatureText.size()) {
+      OS << signatureText.substr(currentPos);
+    }
+
+    if (!Signature.DocComment.empty()) {
+      OS << "; Documentation=";
+      printWithEscaping(Signature.DocComment, OS);
+    }
+
+    OS << "\n";
+  }
+
+  OS << "End signatures\n";
+}
+
+static int printSignatureHelpResults(
+    CancellableResult<SignatureHelpResults> CancellableResult) {
+  llvm::raw_fd_ostream &OS = llvm::outs();
+  return printResult<SignatureHelpResults>(
+      CancellableResult, [&](const SignatureHelpResults &Results) {
+        if (Results.Result) {
+          llvm::BumpPtrAllocator Allocator;
+          SignatureHelpFormatter Formatter(Allocator);
+          auto FormattedResult = Formatter.format(*Results.Result);
+          printSignatureHelpResultsImpl(FormattedResult, OS);
+        } else {
+          OS << "No signature help results\n";
+        }
+        return 0;
+      });
+}
+
 static int printCodeCompletionResults(
     CancellableResult<CodeCompleteResult> CancellableResult,
     bool IncludeKeywords, bool IncludeComments, bool IncludeSourceText,
@@ -1463,6 +1561,27 @@ static int printCodeCompletionResults(
       });
 }
 
+static int doSignatureHelp(const CompilerInvocation &InitInvok,
+                           StringRef SourceFilename,
+                           StringRef SecondSourceFileName,
+                           StringRef SignatureHelpToken,
+                           bool SignatureHelpDiagnostics) {
+  return performWithCompletionLikeOperationParams(
+      InitInvok, SourceFilename, SecondSourceFileName, SignatureHelpToken,
+      SignatureHelpDiagnostics,
+      [&](CompletionLikeOperationParams Params) -> bool {
+        IDEInspectionInstance Inst(std::make_shared<PluginRegistry>());
+        int ExitCode = 2;
+        Inst.signatureHelp(Params.Invocation, Params.Args, Params.FileSystem,
+                           Params.CompletionBuffer, Params.Offset, Params.DiagC,
+                           /*CancellationFlag=*/nullptr,
+                           [&](CancellableResult<SignatureHelpResults> Result) {
+                             ExitCode = printSignatureHelpResults(Result);
+                           });
+        return ExitCode;
+      });
+}
+
 static int
 doCodeCompletion(const CompilerInvocation &InitInvok, StringRef SourceFilename,
                  StringRef SecondSourceFileName, StringRef CodeCompletionToken,
@@ -3470,19 +3589,6 @@ class ASTCommentPrinter : public ASTWalker {
   ASTCommentPrinter(SourceManager &SM, XMLValidator &TheXMLValidator)
       : OS(llvm::outs()), SM(SM), TheXMLValidator(TheXMLValidator) {}
 
-  void printWithEscaping(StringRef Str) {
-    for (char C : Str) {
-      switch (C) {
-      case '\n': OS << "\\n"; break;
-      case '\r': OS << "\\r"; break;
-      case '\t': OS << "\\t"; break;
-      case '\v': OS << "\\v"; break;
-      case '\f': OS << "\\f"; break;
-      default:   OS << C;     break;
-      }
-    }
-  }
-
   void printDeclName(const ValueDecl *VD) {
     if (auto *NTD = dyn_cast<NominalTypeDecl>(VD->getDeclContext())) {
       Identifier Id = NTD->getName();
@@ -3555,7 +3661,7 @@ class ASTCommentPrinter : public ASTWalker {
     }
     OS << "[";
     for (auto &SRC : RC.Comments)
-      printWithEscaping(SRC.RawText);
+      printWithEscaping(SRC.RawText, OS);
     OS << "]";
   }
 
@@ -3566,7 +3672,7 @@ class ASTCommentPrinter : public ASTWalker {
       return;
     }
     OS << "[";
-    printWithEscaping(Brief);
+    printWithEscaping(Brief, OS);
     OS << "]";
   }
 
@@ -3582,7 +3688,7 @@ class ASTCommentPrinter : public ASTWalker {
       return;
     }
     OS << "[";
-    printWithEscaping(XML);
+    printWithEscaping(XML, OS);
     OS << "]";
 
     auto Status = TheXMLValidator.validate(XML);
@@ -4849,6 +4955,16 @@ int main(int argc, char *argv[]) {
                                       options::ConformingMethodListExpectedTypes);
     break;
 
+  case ActionType::SignatureHelp:
+    if (options::CodeCompletionToken.empty()) {
+      llvm::errs() << "signature help token name required\n";
+      return 1;
+    }
+    ExitCode = doSignatureHelp(
+        InitInvok, options::SourceFilename, options::SecondSourceFilename,
+        options::CodeCompletionToken, options::CodeCompletionDiagnostics);
+    break;
+
   case ActionType::SyntaxColoring:
     ExitCode = doSyntaxColoring(InitInvok,
                                 options::SourceFilename,