Fix TensorFlow module compilation. (#28023)

Fix `KeyPathIterable` derived conformances: `KeyPathIterable.allKeyPaths`
synthesis logic now uses different key-path expression coercion logic
to accommodate upstream type-checker changes.

See TF-575 for more information.

Author: dan-zheng

lib/Sema/DerivedConformanceKeyPathIterable.cpp

@@ -78,8 +78,9 @@ deriveBodyKeyPathIterable_allKeyPaths(AbstractFunctionDecl *funcDecl, void *) {
   auto *parentDC = funcDecl->getDeclContext();
   auto *nominal = parentDC->getSelfNominalTypeDecl();
   auto &C = nominal->getASTContext();
-  auto allKeyPathsInterfaceType = computeAllKeyPathsType(nominal);
-  auto allKeyPathsType = parentDC->mapTypeIntoContext(allKeyPathsInterfaceType);
+  auto partialKeyPathInterfaceType = computePartialKeyPathType(nominal);
+  auto partialKeyPathType =
+      parentDC->mapTypeIntoContext(partialKeyPathInterfaceType);
 
   auto *nominalTypeExpr = TypeExpr::createForDecl(SourceLoc(), nominal,
                                                   funcDecl, /*Implicit*/ true);
@@ -97,17 +98,17 @@ deriveBodyKeyPathIterable_allKeyPaths(AbstractFunctionDecl *funcDecl, void *) {
     auto *dotExpr = new (C)
         UnresolvedDotExpr(nominalTypeExpr, SourceLoc(), member->getFullName(),
                           DeclNameLoc(), /*Implicit*/ true);
-    auto *keyPathExpr =
+    Expr *keyPathExpr =
         new (C) KeyPathExpr(SourceLoc(), dotExpr, nullptr, /*Implicit*/ true);
+    // NOTE(TF-575): Adding an explicit coercion expression here is necessary
+    // due to type-checker changes.
+    keyPathExpr = new (C) CoerceExpr(
+        keyPathExpr, SourceLoc(), TypeLoc::withoutLoc(partialKeyPathType));
     keyPathExprs.push_back(keyPathExpr);
   }
   // Return array of all key path expressions.
   Expr *keyPathsArrayExpr =
       ArrayExpr::create(C, SourceLoc(), keyPathExprs, {}, SourceLoc());
-  // NOTE(TF-575): Adding an explicit coercion expression here is necessary due
-  // to a missing regression.
-  keyPathsArrayExpr = new (C) CoerceExpr(
-      keyPathsArrayExpr, SourceLoc(), TypeLoc::withoutLoc(allKeyPathsType));
   auto *returnStmt = new (C) ReturnStmt(SourceLoc(), keyPathsArrayExpr);
   auto *body = BraceStmt::create(C, SourceLoc(), {returnStmt}, SourceLoc(),
                                  /*Implicit*/ true);

stdlib/public/CMakeLists.txt

@@ -73,8 +73,8 @@ endif()
 # dependency for `numpy.ndarray` bridging to `ShapedArray`/`Tensor`.
 if(SWIFT_BUILD_STDLIB AND SWIFT_ENABLE_TENSORFLOW)
   # TODO: Add TensorFlow support for iOS/Raspberry Pi.
-  #  add_subdirectory(CTensorFlow)
-  #  add_subdirectory(TensorFlow)
+  add_subdirectory(CTensorFlow)
+  add_subdirectory(TensorFlow)
 endif()
 
 if(SWIFT_BUILD_STDLIB OR SWIFT_BUILD_REMOTE_MIRROR)

test/Sema/struct_key_path_iterable.swift

@@ -114,6 +114,26 @@ struct DummyOptimizer<P : KeyPathIterable, Scalar : BinaryFloatingPoint>
   }
 }
 
+// TF-575: Test overloaded key path component name.
+protocol NameLookupConflictProtocol {}
+extension NameLookupConflictProtocol {
+  func member() {}
+}
+struct NameLookupConflict: NameLookupConflictProtocol & KeyPathIterable {
+  // Note: `NameLookupConflict.member` is overloaded with
+  // `MemberNameConflictProtocol.member`.
+  // This makes the following generated code fail:
+  //
+  //   var allKeyPaths: [PartialKeyPath<Self>] {
+  //     [\Self.member]
+  //   }
+  //
+  // error: cannot convert value of type
+  // 'WritableKeyPath<NameLookupConflict, Float>' to expected element type
+  // 'PartialKeyPath<NameLookupConflict>'
+  var member: Float
+}
+
 // Test derived conformances in disallowed contexts.
 
 // expected-error @+3 {{type 'OtherFileNonconforming' does not conform to protocol 'KeyPathIterable'}}