[Callable] 'func call' -> 'func callAsFunction'.

Apply the final naming decision in [SE-0253](https://github.com/apple/swift-evolution/blob/master/proposals/0253-callable.md) to the 'tensorflow' branch implementation.

Author: rxwei

include/swift/AST/Decl.h

@@ -5950,7 +5950,7 @@ class FuncDecl : public AbstractFunctionDecl {
     return Bits.FuncDecl.IsStatic;
   }
   bool isCallable() const {
-    return getName().str() == "call" && isInstanceMember();
+    return getName().str() == "callAsFunction" && isInstanceMember();
   }
   /// \returns the way 'static'/'class' was spelled in the source.
   StaticSpellingKind getStaticSpelling() const {

include/swift/AST/KnownIdentifiers.def

@@ -32,7 +32,7 @@ IDENTIFIER(ArrayLiteralElement)
 IDENTIFIER(atIndexedSubscript)
 IDENTIFIER_(bridgeToObjectiveC)
 // SWIFT_ENABLE_TENSORFLOW
-IDENTIFIER(call)
+IDENTIFIER(callAsFunction)
 IDENTIFIER_WITH_NAME(code_, "_code")
 IDENTIFIER(CodingKeys)
 IDENTIFIER(combine)

lib/Sema/CSApply.cpp

@@ -7140,8 +7140,8 @@ Expr *ExprRewriter::finishApply(ApplyExpr *apply, Type openedType,
     };
 
   // SWIFT_ENABLE_TENSORFLOW
-  // Save the original potentially lvalue function for rewriting call method
-  // applications.
+  // Save the original potentially lvalue function for rewriting
+  // 'callAsFunction' method applications.
   auto *originalFn = fn;
   // SWIFT_ENABLE_TENSORFLOW END
   // The function is always an rvalue.
@@ -7291,7 +7291,7 @@ Expr *ExprRewriter::finishApply(ApplyExpr *apply, Type openedType,
   }
 
   // SWIFT_ENABLE_TENSORFLOW
-  // Handle call method applications.
+  // Handle 'callAsFunction' method applications.
   auto &ctx = cs.getASTContext();
 
   TupleExpr *arg = dyn_cast<TupleExpr>(apply->getArg());

lib/Sema/CSSimplify.cpp

@@ -5827,7 +5827,7 @@ ConstraintSystem::simplifyApplicableFnConstraint(
     auto &ctx = getASTContext();
     // Get all call methods of the nominal type.
     SmallVector<FuncDecl *, 4> callMethods;
-    auto candidates = lookupMember(desugar2, DeclName(ctx.Id_call));
+    auto candidates = lookupMember(desugar2, DeclName(ctx.Id_callAsFunction));
     for (auto entry : candidates) {
       auto callMethod = dyn_cast<FuncDecl>(entry.getValueDecl());
       if (!callMethod)

test/Sema/Inputs/call_method_other_module.swift

@@ -1,13 +1,15 @@
+// SWIFT_ENABLE_TENSORFLOW
+
 public protocol Layer : Differentiable {
   @differentiable
-  func call(_ input: Float) -> Float
+  func callAsFunction(_ input: Float) -> Float
 }
 
 public struct Dense : Differentiable {
   public init() {}
 
   @differentiable
-  public func call(_ input: Float) -> Float {
+  public func callAsFunction(_ input: Float) -> Float {
     return input * 2
   }
 }

test/Sema/call_method_generic.swift

@@ -1,22 +1,22 @@
 // RUN: %target-typecheck-verify-swift
 
 protocol P0 {
-  func call(x: Self)
+  func callAsFunction(x: Self)
 }
 
 struct ConcreteType {
-  func call<T, U>(_ x: T, _ y: U) -> (T, U) {
+  func callAsFunction<T, U>(_ x: T, _ y: U) -> (T, U) {
     return (x, y)
   }
 
-  func call<T, U>(_ fn: @escaping (T) -> U) -> (T) -> U {
+  func callAsFunction<T, U>(_ fn: @escaping (T) -> U) -> (T) -> U {
     return fn
   }
 }
 
 let concrete = ConcreteType()
 _ = concrete(1, 3.0)
-_ = concrete(concrete, concrete.call as ([Int], Float) -> ([Int], Float))
+_ = concrete(concrete, concrete.callAsFunction as ([Int], Float) -> ([Int], Float))
 
 func generic<T, U>(_ x: T, _ y: U) {
   _ = concrete(x, x)
@@ -25,14 +25,14 @@ func generic<T, U>(_ x: T, _ y: U) {
 
 struct GenericType<T : Collection> {
   let collection: T
-  func call<U>(_ x: U) -> Bool where U == T.Element, U : Equatable {
+  func callAsFunction<U>(_ x: U) -> Bool where U == T.Element, U : Equatable {
     return collection.contains(x)
   }
 }
 
 // Test conditional conformance.
 extension GenericType where T.Element : Numeric {
-  func call(initialValue: T.Element) -> T.Element {
+  func callAsFunction(initialValue: T.Element) -> T.Element {
     return collection.reduce(initialValue, +)
   }
 }

test/Sema/call_method_protocol.swift

@@ -1,8 +1,8 @@
 // RUN: %target-typecheck-verify-swift
 
 protocol P0 {
-  // expected-note @+1 {{protocol requires function 'call()' with type '() -> Missing'; do you want to add a stub?}}
-  func call() -> Self
+  // expected-note @+1 {{protocol requires function 'callAsFunction()' with type '() -> Missing'; do you want to add a stub?}}
+  func callAsFunction() -> Self
 }
 func testProtocol(_ x: P0) {
   _ = x()
@@ -12,18 +12,18 @@ func testGeneric<T : P0>(_ x: T) {
 }
 
 protocol P1 {
-  func call() -> Self
+  func callAsFunction() -> Self
 }
 extension P1 {
   // expected-note @+1 {{found this candidate}}
-  func call() -> Self {
+  func callAsFunction() -> Self {
     return self
   }
 }
 protocol P2 {}
 extension P2 {
   // expected-note @+1 {{found this candidate}}
-  func call(x: Int, y: Int) -> Int {
+  func callAsFunction(x: Int, y: Int) -> Int {
     return x + y
   }
 }
@@ -32,13 +32,13 @@ extension P2 {
 struct Missing : P0 {}
 struct S0 : P0 {
   @discardableResult
-  func call() -> S0 { return self }
+  func callAsFunction() -> S0 { return self }
 }
 let s0 = S0()
 s0()
 
 struct S1 : P1 {
-  func call() -> S1 { return self }
+  func callAsFunction() -> S1 { return self }
 }
 
 let s1 = S1()
@@ -47,13 +47,13 @@ _ = s1()()
 struct Conforming : P0 & P1 & P2 {}
 let conforming = Conforming()
 _ = conforming(x: 1, y: 2)
-_ = conforming().call(x:y:)(1, 2)
-_ = conforming.call(x:y:)
-_ = conforming.call // expected-error {{ambiguous use of 'call'}}
+_ = conforming().callAsFunction(x:y:)(1, 2)
+_ = conforming.callAsFunction(x:y:)
+_ = conforming.callAsFunction // expected-error {{ambiguous use of 'callAsFunction'}}
 
 protocol P3 {}
 extension P3 {
-  func call() -> Self { return self }
+  func callAsFunction() -> Self { return self }
 }
 struct S3 : P3 {}
 

test/Sema/call_method_simple.swift

@@ -1,7 +1,7 @@
 // RUN: %target-typecheck-verify-swift
 
 struct SimpleCallable {
-  func call(_ x: Float) -> Float {
+  func callAsFunction(_ x: Float) -> Float {
     return x
   }
 }
@@ -12,20 +12,20 @@ let foo = SimpleCallable()
 _ = foo(1)
 _ = foo(foo(1))
 
-// TODO: Improve this error to match the error using a direct `call` member reference.
+// TODO: Improve this error to match the error using a direct `callAsFunction` member reference.
 // expected-error @+2 {{cannot call value of non-function type 'SimpleCallable'}}
 // expected-error @+1 {{cannot invoke 'foo' with an argument list of type '(Int, Int)'}}
 _ = foo(1, 1)
 // expected-error @+1 {{cannot convert value of type 'SimpleCallable' to specified type '(Float) -> Float'}}
 let _: (Float) -> Float = foo
 
-// Test direct `call` member references.
+// Test direct `callAsFunction` member references.
 
-_ = foo.call(1)
-_ = [1, 2, 3].map(foo.call)
-_ = foo.call(foo(1))
-_ = foo(foo.call(1))
-let _: (Float) -> Float = foo.call
+_ = foo.callAsFunction(1)
+_ = [1, 2, 3].map(foo.callAsFunction)
+_ = foo.callAsFunction(foo(1))
+_ = foo(foo.callAsFunction(1))
+let _: (Float) -> Float = foo.callAsFunction
 
 func callable() -> SimpleCallable {
   return SimpleCallable()
@@ -42,43 +42,43 @@ extension SimpleCallable {
 _ = foo.foo(1)
 _ = foo.bar()(1)
 _ = callable()(1)
-_ = [1, 2, 3].map(foo.foo.call)
-_ = [1, 2, 3].map(foo.bar().call)
-_ = [1, 2, 3].map(callable().call)
+_ = [1, 2, 3].map(foo.foo.callAsFunction)
+_ = [1, 2, 3].map(foo.bar().callAsFunction)
+_ = [1, 2, 3].map(callable().callAsFunction)
 
 struct MultipleArgsCallable {
-  func call(x: Int, y: Float) -> [Int] {
+  func callAsFunction(x: Int, y: Float) -> [Int] {
     return [x]
   }
 }
 
 let bar = MultipleArgsCallable()
 _ = bar(x: 1, y: 1)
-_ = bar.call(x: 1, y: 1)
-_ = bar(x: bar.call(x: 1, y: 1)[0], y: 1)
-_ = bar.call(x: bar(x: 1, y: 1)[0], y: 1)
+_ = bar.callAsFunction(x: 1, y: 1)
+_ = bar(x: bar.callAsFunction(x: 1, y: 1)[0], y: 1)
+_ = bar.callAsFunction(x: bar(x: 1, y: 1)[0], y: 1)
 _ = bar(1, 1) // expected-error {{missing argument labels 'x:y:' in call}}
 
 struct Extended {}
 extension Extended {
   @discardableResult
-  func call() -> Extended {
+  func callAsFunction() -> Extended {
     return self
   }
 }
 var extended = Extended()
-extended()().call()()
+extended()().callAsFunction()()
 
 struct OptionalCallable {
-  func call() -> OptionalCallable? {
+  func callAsFunction() -> OptionalCallable? {
     return self
   }
 }
 var optional = OptionalCallable()
-_ = optional()?.call()?()
+_ = optional()?.callAsFunction()?()
 
 struct Variadic {
-  func call(_ args: Int...) -> [Int] {
+  func callAsFunction(_ args: Int...) -> [Int] {
     return args
   }
 }
@@ -88,36 +88,36 @@ _ = variadic(1, 2, 3)
 
 struct Mutating {
   var x: Int
-  mutating func call() {
+  mutating func callAsFunction() {
     x += 1
   }
 }
 func testMutating(_ x: Mutating, _ y: inout Mutating) {
   _ = x() // expected-error {{cannot use mutating member on immutable value: 'x' is a 'let' constant}}
-  _ = x.call() // expected-error {{cannot use mutating member on immutable value: 'x' is a 'let' constant}}
+  _ = x.callAsFunction() // expected-error {{cannot use mutating member on immutable value: 'x' is a 'let' constant}}
   _ = y()
-  _ = y.call()
+  _ = y.callAsFunction()
 }
 
 struct Inout {
-  func call(_ x: inout Int) {
+  func callAsFunction(_ x: inout Int) {
     x += 5
   }
 }
 func testInout(_ x: Inout, _ arg: inout Int) {
   x(&arg)
-  x.call(&arg)
+  x.callAsFunction(&arg)
   // TODO: Improve this error to match the error using a direct `call` member reference.
   // expected-error @+2 {{cannot invoke 'x' with an argument list of type '(Int)'}}
   // expected-error @+1 {{cannot call value of non-function type 'Inout'}}
   x(arg)
   // expected-error @+1 {{passing value of type 'Int' to an inout parameter requires explicit '&'}}
-  x.call(arg)
+  x.callAsFunction(arg)
 }
 
 struct Autoclosure {
-  func call(_ condition: @autoclosure () -> Bool,
-            _ message: @autoclosure () -> String) {
+  func callAsFunction(_ condition: @autoclosure () -> Bool,
+                      _ message: @autoclosure () -> String) {
     if condition() {
       print(message())
     }
@@ -129,10 +129,10 @@ func testAutoclosure(_ x: Autoclosure) {
 }
 
 struct Throwing {
-  func call() throws -> Throwing {
+  func callAsFunction() throws -> Throwing {
     return self
   }
-  func call(_ f: () throws -> ()) rethrows {
+  func callAsFunction(_ f: () throws -> ()) rethrows {
     try f()
   }
 }
@@ -145,7 +145,7 @@ enum BinaryOperation {
   case add, subtract, multiply, divide
 }
 extension BinaryOperation {
-  func call(_ lhs: Float, _ rhs: Float) -> Float {
+  func callAsFunction(_ lhs: Float, _ rhs: Float) -> Float {
     switch self {
     case .add: return lhs + rhs
     case .subtract: return lhs - rhs
@@ -157,12 +157,12 @@ extension BinaryOperation {
 _ = BinaryOperation.add(1, 2)
 
 class BaseClass {
-  func call() -> Self {
+  func callAsFunction() -> Self {
     return self
   }
 }
 class SubClass : BaseClass {
-  override func call() -> Self {
+  override func callAsFunction() -> Self {
     return self
   }
 }
@@ -173,7 +173,7 @@ func testIUO(a: SimpleCallable!, b: MultipleArgsCallable!, c: Extended!,
   _ = a(1)
   _ = b(x: 1, y: 1)
   _ = c()
-  _ = d()?.call()?()
+  _ = d()?.callAsFunction()?()
   _ = e()
   _ = e(1, 2, 3)
   // FIXME(TF-444): `mutating func call` and IUO doesn't work.