[IDE] Simplify isImplicitSingleExpressionReturn

hamishknight · hamishknight · commit d7fc22aacae5 · 2024-02-07T18:14:23.000Z
Use the generalized implied result logic, and
rename to `isImpliedResult` since that's really
what we're querying here, and it needs to handle
implicit-last-exprs if enabled.
diff --git a/include/swift/IDE/AfterPoundExprCompletion.h b/include/swift/IDE/AfterPoundExprCompletion.h
@@ -26,7 +26,7 @@ namespace ide {
 class AfterPoundExprCompletion : public TypeCheckCompletionCallback {
   struct Result {
     Type ExpectedTy;
-    bool IsImplicitSingleExpressionReturn;
+    bool IsImpliedResult;
 
     /// Whether the surrounding context is async and thus calling async
     /// functions is supported.
diff --git a/include/swift/IDE/CodeCompletionContext.h b/include/swift/IDE/CodeCompletionContext.h
@@ -39,10 +39,10 @@ class CodeCompletionContext {
     /// There is no known contextual type. All types are equally good.
     None,
 
-    /// There is a contextual type from a single-expression closure/function
-    /// body. The context is a hint, and enables unresolved member completion,
-    /// but should not hide any results.
-    SingleExpressionBody,
+    /// There is a contextual type from e.g a single-expression closure/function
+    /// body, where the return is implied. The context is a hint, and enables
+    /// unresolved member completion, but should not hide any results.
+    Implied,
 
     /// There are known contextual types, or there aren't but a nonvoid type is
     /// expected.
diff --git a/include/swift/IDE/CodeCompletionResultType.h b/include/swift/IDE/CodeCompletionResultType.h
@@ -44,12 +44,12 @@ class ExpectedTypeContext {
   /// Pre typechecked type of the expression at the completion position.
   Type IdealType;
 
-  /// Whether the `ExpectedTypes` comes from a single-expression body, e.g.
+  /// Whether the `ExpectedTypes` comes from an implied result, 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 IsImpliedResult = false;
   bool PreferNonVoid = false;
 
   /// If not empty, \c PossibleTypes are ignored and types that have an
@@ -86,7 +86,7 @@ class ExpectedTypeContext {
     if (!IdealType || !Other.IdealType || !IdealType->isEqual(Other.IdealType)) {
       IdealType = Type();
     }
-    IsImplicitSingleExpressionReturn |= Other.IsImplicitSingleExpressionReturn;
+    IsImpliedResult |= Other.IsImpliedResult;
     PreferNonVoid &= Other.PreferNonVoid;
     ExpectedCustomAttributeKinds |= Other.ExpectedCustomAttributeKinds;
   }
@@ -96,7 +96,7 @@ class ExpectedTypeContext {
   void setIdealType(Type IdealType) { this->IdealType = IdealType; }
 
   bool requiresNonVoid() const {
-    if (IsImplicitSingleExpressionReturn)
+    if (IsImpliedResult)
       return false;
     if (PreferNonVoid)
       return true;
@@ -105,13 +105,12 @@ class ExpectedTypeContext {
     return llvm::all_of(PossibleTypes, [](Type Ty) { return !Ty->isVoid(); });
   }
 
-  bool isImplicitSingleExpressionReturn() const {
-    return IsImplicitSingleExpressionReturn;
+  bool isImpliedResult() const {
+    return IsImpliedResult;
   }
 
-  void
-  setIsImplicitSingleExpressionReturn(bool IsImplicitSingleExpressionReturn) {
-    this->IsImplicitSingleExpressionReturn = IsImplicitSingleExpressionReturn;
+  void setIsImpliedResult(bool IsImpliedResult) {
+    this->IsImpliedResult = IsImpliedResult;
   }
 
   bool getPreferNonVoid() const { return PreferNonVoid; }
diff --git a/include/swift/IDE/CompletionLookup.h b/include/swift/IDE/CompletionLookup.h
@@ -234,11 +234,9 @@ class CompletionLookup final : public swift::VisibleDeclConsumer {
   void setIsStaticMetatype(bool value) { IsStaticMetatype = value; }
 
   void setExpectedTypes(
-      ArrayRef<Type> Types, bool isImplicitSingleExpressionReturn,
-      bool preferNonVoid = false,
+      ArrayRef<Type> Types, bool isImpliedResult, bool preferNonVoid = false,
       OptionSet<CustomAttributeKind> expectedCustomAttributeKinds = {}) {
-    expectedTypeContext.setIsImplicitSingleExpressionReturn(
-        isImplicitSingleExpressionReturn);
+    expectedTypeContext.setIsImpliedResult(isImpliedResult);
     expectedTypeContext.setPreferNonVoid(preferNonVoid);
     expectedTypeContext.setPossibleTypes(Types);
     expectedTypeContext.setExpectedCustomAttributeKinds(
@@ -269,8 +267,8 @@ class CompletionLookup final : public swift::VisibleDeclConsumer {
     if (expectedTypeContext.empty() &&
         !expectedTypeContext.getPreferNonVoid()) {
       return CodeCompletionContext::TypeContextKind::None;
-    } else if (expectedTypeContext.isImplicitSingleExpressionReturn()) {
-      return CodeCompletionContext::TypeContextKind::SingleExpressionBody;
+    } else if (expectedTypeContext.isImpliedResult()) {
+      return CodeCompletionContext::TypeContextKind::Implied;
     } else {
       return CodeCompletionContext::TypeContextKind::Required;
     }
diff --git a/include/swift/IDE/ExprCompletion.h b/include/swift/IDE/ExprCompletion.h
@@ -23,9 +23,9 @@ namespace ide {
 class ExprTypeCheckCompletionCallback : public TypeCheckCompletionCallback {
 public:
   struct Result {
-    /// If the code completion expression is an implicit return in a
+    /// If the code completion expression is an implied result, e.g in a
     /// single-expression closure.
-    bool IsImplicitSingleExpressionReturn;
+    bool IsImpliedResult;
 
     /// Whether the surrounding context is async and thus calling async
     /// functions is supported.
@@ -75,7 +75,7 @@ class ExprTypeCheckCompletionCallback : public TypeCheckCompletionCallback {
   /// If \c AddUnresolvedMemberCompletions is false, the
   /// \p UnresolvedMemberBaseType is ignored.
   void addResult(
-      bool IsImplicitSingleExpressionReturn, bool IsInAsyncContext,
+      bool IsImpliedResult, bool IsInAsyncContext,
       Type UnresolvedMemberBaseType,
       llvm::SmallDenseMap<const VarDecl *, Type> SolutionSpecificVarTypes);
 
diff --git a/include/swift/IDE/PostfixCompletion.h b/include/swift/IDE/PostfixCompletion.h
@@ -50,12 +50,12 @@ class PostfixCompletionCallback : public TypeCheckCompletionCallback {
     /// we know that we can't retrieve a value from it anymore.
     bool ExpectsNonVoid;
 
-    /// If the code completion expression occurs as a single statement in a
-    /// single-expression closure. In such cases we don't want to disfavor
-    /// results that produce 'Void' because the user might intend to make the
-    /// closure a multi-statment closure, in which case this expression is no
-    /// longer implicitly returned.
-    bool IsImplicitSingleExpressionReturn;
+    /// If the code completion expression occurs as e.g a single statement in a
+    /// single-expression closure, where the return is implied. In such cases
+    /// we don't want to disfavor results that produce 'Void' because the user
+    /// might intend to make the closure a multi-statment closure, in which case
+    /// this expression is no longer implicitly returned.
+    bool IsImpliedResult;
 
     /// Whether the surrounding context is async and thus calling async
     /// functions is supported.
diff --git a/include/swift/IDE/TypeCheckCompletionCallback.h b/include/swift/IDE/TypeCheckCompletionCallback.h
@@ -119,17 +119,17 @@ struct WithSolutionSpecificVarTypesRAII {
   static void setInterfaceType(VarDecl *VD, Type Ty);
 };
 
-/// Whether the given completion expression is the only expression in its
-/// containing closure or function body and its value is implicitly returned.
+/// Whether the given completion expression is an implied result of a closure
+/// or function (e.g in a single-expression closure where the return is
+/// implicit).
 ///
 /// If these conditions are met, code completion needs to avoid penalizing
 /// completion results that don't match the expected return type when
 /// computing type relations, as since no return statement was explicitly
 /// written by the user, it's possible they intend the single expression not
 /// as the return value but merely the first entry in a multi-statement body
 /// they just haven't finished writing yet.
-bool isImplicitSingleExpressionReturn(constraints::ConstraintSystem &CS,
-                                      Expr *CompletionExpr);
+bool isImpliedResult(const constraints::Solution &S, Expr *CompletionExpr);
 
 /// Returns \c true iff the decl context \p DC allows calling async functions.
 bool isContextAsync(const constraints::Solution &S, DeclContext *DC);
diff --git a/include/swift/IDE/UnresolvedMemberCompletion.h b/include/swift/IDE/UnresolvedMemberCompletion.h
@@ -27,7 +27,7 @@ class UnresolvedMemberTypeCheckCompletionCallback
     : public TypeCheckCompletionCallback {
   struct Result {
     Type ExpectedTy;
-    bool IsImplicitSingleExpressionReturn;
+    bool IsImpliedResult;
 
     /// Whether the surrounding context is async and thus calling async
     /// functions is supported.
diff --git a/lib/IDE/AfterPoundExprCompletion.cpp b/lib/IDE/AfterPoundExprCompletion.cpp
@@ -22,7 +22,6 @@ using namespace swift::constraints;
 using namespace swift::ide;
 
 void AfterPoundExprCompletion::sawSolutionImpl(const constraints::Solution &S) {
-  auto &CS = S.getConstraintSystem();
   Type ExpectedTy = getTypeForCompletion(S, CompletionExpr);
 
   bool IsAsync = isContextAsync(S, DC);
@@ -32,8 +31,8 @@ void AfterPoundExprCompletion::sawSolutionImpl(const constraints::Solution &S) {
     return R.ExpectedTy->isEqual(ExpectedTy);
   };
   if (!llvm::any_of(Results, IsEqual)) {
-    bool SingleExprBody = isImplicitSingleExpressionReturn(CS, CompletionExpr);
-    Results.push_back({ExpectedTy, SingleExprBody, IsAsync});
+    bool IsImpliedResult = isImpliedResult(S, CompletionExpr);
+    Results.push_back({ExpectedTy, IsImpliedResult, IsAsync});
   }
 }
 
@@ -50,8 +49,7 @@ void AfterPoundExprCompletion::collectResults(
   UnifiedTypeContext.setPreferNonVoid(true);
 
   for (auto &Result : Results) {
-    Lookup.setExpectedTypes({Result.ExpectedTy},
-                            Result.IsImplicitSingleExpressionReturn,
+    Lookup.setExpectedTypes({Result.ExpectedTy}, Result.IsImpliedResult,
                             /*expectsNonVoid=*/true);
     Lookup.addPoundAvailable(ParentStmtKind);
     Lookup.addObjCPoundKeywordCompletions(/*needPound=*/false);
diff --git a/lib/IDE/ArgumentCompletion.cpp b/lib/IDE/ArgumentCompletion.cpp
@@ -346,8 +346,7 @@ void ArgumentTypeCheckCompletionCallback::collectResults(
   for (auto &Result : Results) {
     if (Result.IncludeSignature) {
       Lookup.setHaveLParen(true);
-      Lookup.setExpectedTypes(ExpectedCallTypes,
-                              /*isImplicitSingleExpressionReturn=*/false);
+      Lookup.setExpectedTypes(ExpectedCallTypes, /*isImpliedResult=*/false);
 
       auto SemanticContext = SemanticContextKind::None;
       NominalTypeDecl *BaseNominal = nullptr;
diff --git a/lib/IDE/CodeCompletion.cpp b/lib/IDE/CodeCompletion.cpp
@@ -1834,8 +1834,7 @@ void CodeCompletionCallbacksImpl::doneParsing(SourceFile *SrcFile) {
       ExpectedCustomAttributeKinds |= CustomAttributeKind::DeclMacro;
     }
 
-    Lookup.setExpectedTypes(/*Types=*/{},
-                            /*isImplicitSingleExpressionReturn=*/false,
+    Lookup.setExpectedTypes(/*Types=*/{}, /*isImpliedResult=*/false,
                             /*preferNonVoid=*/false,
                             ExpectedCustomAttributeKinds);
 
diff --git a/lib/IDE/CodeCompletionResultType.cpp b/lib/IDE/CodeCompletionResultType.cpp
@@ -428,25 +428,25 @@ calculateMaxTypeRelation(Type Ty, const ExpectedTypeContext &typeContext,
 
   auto Result = TypeRelation::Unrelated;
   for (auto expectedTy : typeContext.getPossibleTypes()) {
-    // Do not use Void type context for a single-expression body, since the
-    // implicit return does not constrain the expression.
+    // Do not use Void type context for an implied result such as a
+    // single-expression closure body, since the implicit return does not
+    // constrain the expression.
     //
     //     { ... -> ()  in x } // x can be anything
     //
     // This behaves differently from explicit return, and from non-Void:
     //
     //     { ... -> Int in x }        // x must be Int
     //     { ... -> ()  in return x } // x must be Void
-    if (typeContext.isImplicitSingleExpressionReturn() && expectedTy->isVoid())
+    if (typeContext.isImpliedResult() && expectedTy->isVoid())
       continue;
 
     Result = std::max(Result, calculateTypeRelation(Ty, expectedTy, DC));
   }
 
-  // Map invalid -> unrelated when in a single-expression body, since the
-  // input may be incomplete.
-  if (typeContext.isImplicitSingleExpressionReturn() &&
-      Result == TypeRelation::Invalid)
+  // Map invalid -> unrelated for an implied result, since the input may be
+  // incomplete.
+  if (typeContext.isImpliedResult() && Result == TypeRelation::Invalid)
     Result = TypeRelation::Unrelated;
 
   return Result;
diff --git a/lib/IDE/ExprCompletion.cpp b/lib/IDE/ExprCompletion.cpp
@@ -39,8 +39,7 @@ static bool solutionSpecificVarTypesEqual(
 
 bool ExprTypeCheckCompletionCallback::Result::operator==(
     const Result &Other) const {
-  return IsImplicitSingleExpressionReturn ==
-             Other.IsImplicitSingleExpressionReturn &&
+  return IsImpliedResult == Other.IsImpliedResult &&
          IsInAsyncContext == Other.IsInAsyncContext &&
          nullableTypesEqual(UnresolvedMemberBaseType,
                             Other.UnresolvedMemberBaseType) &&
@@ -59,13 +58,12 @@ void ExprTypeCheckCompletionCallback::addExpectedType(Type ExpectedType) {
 }
 
 void ExprTypeCheckCompletionCallback::addResult(
-    bool IsImplicitSingleExpressionReturn, bool IsInAsyncContext,
-    Type UnresolvedMemberBaseType,
+    bool IsImpliedResult, bool IsInAsyncContext, Type UnresolvedMemberBaseType,
     llvm::SmallDenseMap<const VarDecl *, Type> SolutionSpecificVarTypes) {
   if (!AddUnresolvedMemberCompletions) {
     UnresolvedMemberBaseType = Type();
   }
-  Result NewResult = {IsImplicitSingleExpressionReturn, IsInAsyncContext,
+  Result NewResult = {IsImpliedResult, IsInAsyncContext,
                       UnresolvedMemberBaseType, SolutionSpecificVarTypes};
   if (llvm::is_contained(Results, NewResult)) {
     return;
@@ -75,22 +73,18 @@ void ExprTypeCheckCompletionCallback::addResult(
 
 void ExprTypeCheckCompletionCallback::sawSolutionImpl(
     const constraints::Solution &S) {
-  auto &CS = S.getConstraintSystem();
-
   Type ExpectedTy = getTypeForCompletion(S, CompletionExpr);
-
-  bool ImplicitReturn = isImplicitSingleExpressionReturn(CS, CompletionExpr);
-
+  bool IsImpliedResult = isImpliedResult(S, CompletionExpr);
   bool IsAsync = isContextAsync(S, DC);
 
   llvm::SmallDenseMap<const VarDecl *, Type> SolutionSpecificVarTypes;
   getSolutionSpecificVarTypes(S, SolutionSpecificVarTypes);
 
-  addResult(ImplicitReturn, IsAsync, ExpectedTy, SolutionSpecificVarTypes);
+  addResult(IsImpliedResult, IsAsync, ExpectedTy, SolutionSpecificVarTypes);
   addExpectedType(ExpectedTy);
 
   if (auto PatternMatchType = getPatternMatchType(S, CompletionExpr)) {
-    addResult(ImplicitReturn, IsAsync, PatternMatchType,
+    addResult(IsImpliedResult, IsAsync, PatternMatchType,
               SolutionSpecificVarTypes);
     addExpectedType(PatternMatchType);
   }
@@ -111,8 +105,7 @@ void ExprTypeCheckCompletionCallback::collectResults(
   for (auto &Result : Results) {
     WithSolutionSpecificVarTypesRAII VarTypes(Result.SolutionSpecificVarTypes);
 
-    Lookup.setExpectedTypes(ExpectedTypes,
-                            Result.IsImplicitSingleExpressionReturn);
+    Lookup.setExpectedTypes(ExpectedTypes, Result.IsImpliedResult);
     Lookup.setCanCurrDeclContextHandleAsync(Result.IsInAsyncContext);
     Lookup.setSolutionSpecificVarTypes(Result.SolutionSpecificVarTypes);
 
diff --git a/lib/IDE/PostfixCompletion.cpp b/lib/IDE/PostfixCompletion.cpp
@@ -64,7 +64,7 @@ void PostfixCompletionCallback::Result::merge(const Result &Other,
     ExpectedTypes.push_back(OtherExpectedTy);
   }
   ExpectsNonVoid &= Other.ExpectsNonVoid;
-  IsImplicitSingleExpressionReturn |= Other.IsImplicitSingleExpressionReturn;
+  IsImpliedResult |= Other.IsImpliedResult;
   IsInAsyncContext |= Other.IsInAsyncContext;
 }
 
@@ -213,8 +213,7 @@ void PostfixCompletionCallback::sawSolutionImpl(
     }
   }
 
-  bool IsImplicitSingleExpressionReturn =
-      isImplicitSingleExpressionReturn(CS, CompletionExpr);
+  bool IsImpliedResult = isImpliedResult(S, CompletionExpr);
 
   bool IsInAsyncContext = isContextAsync(S, DC);
   llvm::DenseMap<AbstractClosureExpr *, ActorIsolation>
@@ -232,7 +231,7 @@ void PostfixCompletionCallback::sawSolutionImpl(
       BaseIsStaticMetaType,
       ExpectedTypes,
       ExpectsNonVoid,
-      IsImplicitSingleExpressionReturn,
+      IsImpliedResult,
       IsInAsyncContext,
       ClosureActorIsolations
   };
@@ -448,8 +447,7 @@ void PostfixCompletionCallback::collectResults(
     if (!ProcessedBaseTypes.contains(Result.BaseTy)) {
       Lookup.getPostfixKeywordCompletions(Result.BaseTy, BaseExpr);
     }
-    Lookup.setExpectedTypes(Result.ExpectedTypes,
-                            Result.IsImplicitSingleExpressionReturn,
+    Lookup.setExpectedTypes(Result.ExpectedTypes, Result.IsImpliedResult,
                             Result.ExpectsNonVoid);
     if (isDynamicLookup(Result.BaseTy))
       Lookup.setIsDynamicLookup();
diff --git a/lib/IDE/TypeCheckCompletionCallback.cpp b/lib/IDE/TypeCheckCompletionCallback.cpp
@@ -155,20 +155,12 @@ void WithSolutionSpecificVarTypesRAII::setInterfaceType(VarDecl *VD, Type Ty) {
                                             std::move(Ty));
 }
 
-bool swift::ide::isImplicitSingleExpressionReturn(ConstraintSystem &CS,
-                                                  Expr *CompletionExpr) {
-  Expr *ParentExpr = CS.getParentExpr(CompletionExpr);
-  if (!ParentExpr)
-    return CS.getContextualTypePurpose(CompletionExpr) == CTP_ImpliedReturnStmt;
-
-  if (auto *ParentCE = dyn_cast<ClosureExpr>(ParentExpr)) {
-    if (ParentCE->hasSingleExpressionBody() &&
-        ParentCE->getSingleExpressionBody() == CompletionExpr) {
-      ASTNode Last = ParentCE->getBody()->getLastElement();
-      return !Last.isStmt(StmtKind::Return) || Last.isImplicit();
-    }
-  }
-  return false;
+bool swift::ide::isImpliedResult(const Solution &S, Expr *CompletionExpr) {
+  auto &CS = S.getConstraintSystem();
+  if (CS.getContextualTypePurpose(CompletionExpr) == CTP_ImpliedReturnStmt)
+    return true;
+
+  return S.isImpliedResult(CompletionExpr).has_value();
 }
 
 bool swift::ide::isContextAsync(const constraints::Solution &S,
diff --git a/lib/IDE/UnresolvedMemberCompletion.cpp b/lib/IDE/UnresolvedMemberCompletion.cpp
