[SourceKit] Compute code completion type relation when wrapping a ContextFreeCodeCompletionResult in a CodeCompletionResult

[CodeCompletion] Make ExpectedTypeContext a class with explicit getters/setters

This simplifies debugging because you can break when the possible types are set and you can also search for references to `setPossibleType` to figure out where the expected types are being set.

Author: ahoppen

Diff for: include/swift/IDE/CodeCompletion.h

@@ -13,6 +13,7 @@
 #ifndef SWIFT_IDE_CODECOMPLETION_H
 #define SWIFT_IDE_CODECOMPLETION_H
 
+#include "CodeCompletionResultType.h"
 #include "swift/AST/Identifier.h"
 #include "swift/Basic/Debug.h"
 #include "swift/Basic/LLVM.h"
@@ -701,31 +702,6 @@ enum class CodeCompletionResultKind : uint8_t {
   MAX_VALUE = BuiltinOperator
 };
 
-/// Describes the relationship between the type of the completion results and
-/// the expected type at the code completion position.
-enum class CodeCompletionResultTypeRelation : uint8_t {
-  /// The result does not have a type (e.g. keyword).
-  NotApplicable,
-
-  /// The type relation have not been calculated.
-  Unknown,
-
-  /// The relationship of the result's type to the expected type is not
-  /// invalid, not convertible, and not identical.
-  Unrelated,
-
-  /// The result's type is invalid at the expected position.
-  Invalid,
-
-  /// The result's type is convertible to the type of the expected.
-  Convertible,
-
-  /// The result's type is identical to the type of the expected.
-  Identical,
-
-  MAX_VALUE = Identical
-};
-
 /// The parts of a \c CodeCompletionResult that are not dependent on the context
 /// it appears in and can thus be cached.
 class ContextFreeCodeCompletionResult {
@@ -749,6 +725,7 @@ class ContextFreeCodeCompletionResult {
   StringRef ModuleName;
   StringRef BriefDocComment;
   ArrayRef<StringRef> AssociatedUSRs;
+  CodeCompletionResultType ResultType;
 
   ContextFreeNotRecommendedReason NotRecommended : 3;
   static_assert(int(ContextFreeNotRecommendedReason::MAX_VALUE) < 1 << 3, "");
@@ -772,13 +749,15 @@ class ContextFreeCodeCompletionResult {
       CodeCompletionOperatorKind KnownOperatorKind, bool IsSystem,
       CodeCompletionString *CompletionString, StringRef ModuleName,
       StringRef BriefDocComment, ArrayRef<StringRef> AssociatedUSRs,
+      CodeCompletionResultType ResultType,
       ContextFreeNotRecommendedReason NotRecommended,
       CodeCompletionDiagnosticSeverity DiagnosticSeverity,
       StringRef DiagnosticMessage)
       : Kind(Kind), KnownOperatorKind(KnownOperatorKind), IsSystem(IsSystem),
         CompletionString(CompletionString), ModuleName(ModuleName),
         BriefDocComment(BriefDocComment), AssociatedUSRs(AssociatedUSRs),
-        NotRecommended(NotRecommended), DiagnosticSeverity(DiagnosticSeverity),
+        ResultType(ResultType), NotRecommended(NotRecommended),
+        DiagnosticSeverity(DiagnosticSeverity),
         DiagnosticMessage(DiagnosticMessage) {
     this->AssociatedKind.Opaque = AssociatedKind;
     assert((NotRecommended == ContextFreeNotRecommendedReason::None) ==
@@ -805,13 +784,14 @@ class ContextFreeCodeCompletionResult {
   ContextFreeCodeCompletionResult(
       CodeCompletionResultKind Kind, CodeCompletionString *CompletionString,
       CodeCompletionOperatorKind KnownOperatorKind, StringRef BriefDocComment,
+      CodeCompletionResultType ResultType,
       ContextFreeNotRecommendedReason NotRecommended,
       CodeCompletionDiagnosticSeverity DiagnosticSeverity,
       StringRef DiagnosticMessage)
       : ContextFreeCodeCompletionResult(
             Kind, /*AssociatedKind=*/0, KnownOperatorKind,
             /*IsSystem=*/false, CompletionString, /*ModuleName=*/"",
-            BriefDocComment, /*AssociatedUSRs=*/{}, NotRecommended,
+            BriefDocComment, /*AssociatedUSRs=*/{}, ResultType, NotRecommended,
             DiagnosticSeverity, DiagnosticMessage) {}
 
   /// Constructs a \c Keyword result.
@@ -821,12 +801,14 @@ class ContextFreeCodeCompletionResult {
   /// same \c CodeCompletionResultSink as the result itself.
   ContextFreeCodeCompletionResult(CodeCompletionKeywordKind Kind,
                                   CodeCompletionString *CompletionString,
-                                  StringRef BriefDocComment)
+                                  StringRef BriefDocComment,
+                                  CodeCompletionResultType ResultType)
       : ContextFreeCodeCompletionResult(
             CodeCompletionResultKind::Keyword, static_cast<uint8_t>(Kind),
             CodeCompletionOperatorKind::None, /*IsSystem=*/false,
             CompletionString, /*ModuleName=*/"", BriefDocComment,
-            /*AssociatedUSRs=*/{}, ContextFreeNotRecommendedReason::None,
+            /*AssociatedUSRs=*/{}, ResultType,
+            ContextFreeNotRecommendedReason::None,
             CodeCompletionDiagnosticSeverity::None, /*DiagnosticMessage=*/"") {}
 
   /// Constructs a \c Literal result.
@@ -835,13 +817,15 @@ class ContextFreeCodeCompletionResult {
   /// result, typically by storing them in the same \c CodeCompletionResultSink
   /// as the result itself.
   ContextFreeCodeCompletionResult(CodeCompletionLiteralKind LiteralKind,
-                                  CodeCompletionString *CompletionString)
+                                  CodeCompletionString *CompletionString,
+                                  CodeCompletionResultType ResultType)
       : ContextFreeCodeCompletionResult(
             CodeCompletionResultKind::Literal,
             static_cast<uint8_t>(LiteralKind), CodeCompletionOperatorKind::None,
             /*IsSystem=*/false, CompletionString, /*ModuleName=*/"",
             /*BriefDocComment=*/"",
-            /*AssociatedUSRs=*/{}, ContextFreeNotRecommendedReason::None,
+            /*AssociatedUSRs=*/{}, ResultType,
+            ContextFreeNotRecommendedReason::None,
             CodeCompletionDiagnosticSeverity::None, /*DiagnosticMessage=*/"") {}
 
   /// Constructs a \c Declaration result.
@@ -852,7 +836,7 @@ class ContextFreeCodeCompletionResult {
   ContextFreeCodeCompletionResult(
       CodeCompletionString *CompletionString, const Decl *AssociatedDecl,
       StringRef ModuleName, StringRef BriefDocComment,
-      ArrayRef<StringRef> AssociatedUSRs,
+      ArrayRef<StringRef> AssociatedUSRs, CodeCompletionResultType ResultType,
       ContextFreeNotRecommendedReason NotRecommended,
       CodeCompletionDiagnosticSeverity DiagnosticSeverity,
       StringRef DiagnosticMessage)
@@ -861,7 +845,7 @@ class ContextFreeCodeCompletionResult {
             static_cast<uint8_t>(getCodeCompletionDeclKind(AssociatedDecl)),
             CodeCompletionOperatorKind::None, getDeclIsSystem(AssociatedDecl),
             CompletionString, ModuleName, BriefDocComment, AssociatedUSRs,
-            NotRecommended, DiagnosticSeverity, DiagnosticMessage) {
+            ResultType, NotRecommended, DiagnosticSeverity, DiagnosticMessage) {
     assert(AssociatedDecl && "should have a decl");
   }
 
@@ -899,6 +883,8 @@ class ContextFreeCodeCompletionResult {
 
   ArrayRef<StringRef> getAssociatedUSRs() const { return AssociatedUSRs; }
 
+  const CodeCompletionResultType &getResultType() const { return ResultType; }
+
   ContextFreeNotRecommendedReason getNotRecommendedReason() const {
     return NotRecommended;
   }
@@ -962,9 +948,7 @@ class CodeCompletionResult {
   CodeCompletionResultTypeRelation TypeDistance : 3;
   static_assert(int(CodeCompletionResultTypeRelation::MAX_VALUE) < 1 << 3, "");
 
-public:
-  /// Enrich a \c ContextFreeCodeCompletionResult with the following contextual
-  /// information.
+  /// Memberwise initializer
   /// The \c ContextFree result must outlive this result. Typically, this is
   /// done by allocating the two in the same sink or adopting the context free
   /// sink in the sink that allocates this result.
@@ -981,6 +965,23 @@ class CodeCompletionResult {
         DiagnosticMessage(DiagnosticMessage), NumBytesToErase(NumBytesToErase),
         TypeDistance(TypeDistance) {}
 
+public:
+  /// Enrich a \c ContextFreeCodeCompletionResult with the following contextual
+  /// information.
+  /// This computes the type relation between the completion item and its
+  /// expected type context.
+  /// The \c ContextFree result must outlive this result. Typically, this is
+  /// done by allocating the two in the same sink or adopting the context free
+  /// sink in the sink that allocates this result.
+  CodeCompletionResult(const ContextFreeCodeCompletionResult &ContextFree,
+                       SemanticContextKind SemanticContext,
+                       CodeCompletionFlair Flair, uint8_t NumBytesToErase,
+                       const ExpectedTypeContext *TypeContext,
+                       const DeclContext *DC,
+                       ContextualNotRecommendedReason NotRecommended,
+                       CodeCompletionDiagnosticSeverity DiagnosticSeverity,
+                       StringRef DiagnosticMessage);
+
   const ContextFreeCodeCompletionResult &getContextFreeResult() const {
     return ContextFree;
   }
@@ -997,7 +998,16 @@ class CodeCompletionResult {
   /// context free result outlives the result the result returned by this
   /// method.
   CodeCompletionResult *withFlair(CodeCompletionFlair newFlair,
-                                  CodeCompletionResultSink &Sink);
+                                  CodeCompletionResultSink &Sink) const;
+
+  /// Copy this result to \p Sink with \p newFlair . Note that this does NOT
+  /// copy the context free result. Thus the caller needs to ensure that the
+  /// context free result outlives the result the result returned by this
+  /// method.
+  CodeCompletionResult *withContextFreeResultSemanticContextAndFlair(
+      const ContextFreeCodeCompletionResult &NewContextFree,
+      SemanticContextKind NewSemanticContext, CodeCompletionFlair NewFlair,
+      CodeCompletionResultSink &Sink) const;
 
   CodeCompletionResultKind getKind() const {
     return getContextFreeResult().getKind();

Diff for: include/swift/IDE/CodeCompletionResultType.h

@@ -0,0 +1,162 @@
+//===--- CodeCompletionResultType.h -----------------------------*- C++ -*-===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2022 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_CODECOMPLETIONRESULTTYPE_H
+#define SWIFT_IDE_CODECOMPLETIONRESULTTYPE_H
+
+#include "swift/AST/Types.h"
+#include "swift/Basic/LLVM.h"
+
+namespace swift {
+namespace ide {
+
+/// The expected contextual type(s) for code-completion.
+class ExpectedTypeContext {
+  /// Possible types of the code completion expression.
+  llvm::SmallVector<Type, 4> PossibleTypes;
+
+  /// Pre typechecked type of the expression at the completion position.
+  Type IdealType;
+
+  /// Whether the `ExpectedTypes` comes from a single-expression body, e.g.
+  /// `foo({ here })`.
+  ///
+  /// Since the input may be incomplete, we take into account that the types are
+  /// only a hint.
+  bool IsImplicitSingleExpressionReturn = false;
+  bool PreferNonVoid = false;
+
+public:
+  ExpectedTypeContext() = default;
+
+  bool empty() const { return PossibleTypes.empty(); }
+
+  ArrayRef<Type> getPossibleTypes() const { return PossibleTypes; }
+
+  void setPossibleTypes(ArrayRef<Type> Types) {
+    PossibleTypes.clear();
+    PossibleTypes.reserve(Types.size());
+    for (auto T : Types) {
+      if (T) {
+        PossibleTypes.push_back(T);
+      }
+    }
+  }
+
+  Type getIdealType() const { return IdealType; }
+
+  void setIdealType(Type IdealType) { this->IdealType = IdealType; }
+
+  bool requiresNonVoid() const {
+    if (IsImplicitSingleExpressionReturn)
+      return false;
+    if (PreferNonVoid)
+      return true;
+    if (PossibleTypes.empty())
+      return false;
+    return llvm::all_of(PossibleTypes, [](Type Ty) { return !Ty->isVoid(); });
+  }
+
+  bool isImplicitSingleExpressionReturn() const {
+    return IsImplicitSingleExpressionReturn;
+  }
+
+  void
+  setIsImplicitSingleExpressionReturn(bool IsImplicitSingleExpressionReturn) {
+    this->IsImplicitSingleExpressionReturn = IsImplicitSingleExpressionReturn;
+  }
+
+  bool getPreferNonVoid() const { return PreferNonVoid; }
+
+  void setPreferNonVoid(bool PreferNonVoid) {
+    this->PreferNonVoid = PreferNonVoid;
+  }
+};
+
+/// Describes the relationship between the type of the completion results and
+/// the expected type at the code completion position.
+enum class CodeCompletionResultTypeRelation : uint8_t {
+  /// The result does not have a type (e.g. keyword).
+  NotApplicable,
+
+  /// The type relation have not been calculated.
+  Unknown,
+
+  /// The relationship of the result's type to the expected type is not
+  /// invalid, not convertible, and not identical.
+  Unrelated,
+
+  /// The result's type is invalid at the expected position.
+  Invalid,
+
+  /// The result's type is convertible to the type of the expected.
+  Convertible,
+
+  /// The result's type is identical to the type of the expected.
+  Identical,
+
+  MAX_VALUE = Identical
+};
+
+/// The type returned by a \c ContextFreeCodeCompletionResult. Can be either of
+/// the following:
+///  - Have the NotApplicable flag set: The completion result doesn't produce
+///    something that's valid inside an expression like a keyword
+///  - An null type if the completion result produces something that's
+///    valid inside an expression but the result type isn't known
+///  - A proper type if the type produced by this completion result is known
+class CodeCompletionResultType {
+public:
+  enum class Flags : unsigned {
+    IsNotApplicable = 1 << 0,
+    /// If \p AlsoConsiderMetatype is set the code completion item will be
+    /// considered as producing the declared interface type (which is passed as
+    /// \p ResultTypes ) as well as the corresponding metatype.
+    /// This allows us to suggest 'Int' as 'Identical' for both of the following
+    /// functions
+    ///
+    ///   func receiveInstance(_: Int) {}
+    ///   func receiveMetatype(_: Int.Type) {}
+    AlsoConsiderMetatype = 1 << 1
+  };
+
+private:
+  llvm::PointerIntPair<Type, 2, OptionSet<Flags>> TypeAndFlags;
+
+  CodeCompletionResultType(Type Ty, OptionSet<Flags> Flag)
+      : TypeAndFlags(Ty, Flag) {}
+
+public:
+  static CodeCompletionResultType notApplicable() {
+    return CodeCompletionResultType(Type(), Flags::IsNotApplicable);
+  }
+  static CodeCompletionResultType unknown() {
+    return CodeCompletionResultType(Type(), /*Flags=*/0);
+  }
+  CodeCompletionResultType(Type Ty, bool AlsoConsiderMetatype = false)
+      : CodeCompletionResultType(Ty, AlsoConsiderMetatype
+                                         ? Flags::AlsoConsiderMetatype
+                                         : OptionSet<Flags>()) {}
+
+  bool isNotApplicable() const {
+    return TypeAndFlags.getInt().contains(Flags::IsNotApplicable);
+  }
+
+  /// Calculates the type realtion of this type to the given
+  CodeCompletionResultTypeRelation
+  calculateTypeRelation(const ExpectedTypeContext *TypeContext,
+                        const DeclContext *DC) const;
+};
+} // namespace ide
+} // namespace swift
+
+#endif // SWIFT_IDE_CODECOMPLETIONRESULTTYPE_H

Diff for: lib/IDE/CMakeLists.txt

@@ -4,6 +4,7 @@ add_swift_host_library(swiftIDE STATIC
   CodeCompletionCache.cpp
   CodeCompletionDiagnostics.cpp
   CodeCompletionResultPrinter.cpp
+  CodeCompletionResultType.cpp
   CommentConversion.cpp
   CompileInstance.cpp
   CompletionInstance.cpp