Merge pull request #70214 from xedin/rdar-119040159

[CSBindings] Extend early array literal favoring to cover dictionaries

Author: xedin

include/swift/Sema/ConstraintSystem.h

@@ -519,9 +519,9 @@ class TypeVariableType::Implementation {
   /// Determine whether this type variable represents an opened opaque type.
   bool isOpaqueType() const;
 
-  /// Determine whether this type variable represents a type of an array literal
-  /// (represented by `ArrayExpr` in AST).
-  bool isArrayLiteralType() const;
+  /// Determine whether this type variable represents a type of a collection
+  /// literal (represented by `ArrayExpr` and `DictionaryExpr` in AST).
+  bool isCollectionLiteralType() const;
 
   /// Retrieve the representative of the equivalence class to which this
   /// type variable belongs.

lib/Sema/CSBindings.cpp

@@ -1253,10 +1253,10 @@ bool BindingSet::favoredOverDisjunction(Constraint *disjunction) const {
     return boundType->lookThroughAllOptionalTypes()->is<TypeVariableType>();
   }
 
-  // If this is an array literal type, it's preferrable to bind it
+  // If this is a collection literal type, it's preferrable to bind it
   // early (unless it's delayed) to connect all of its elements even
   // if it doesn't have any bindings.
-  if (TypeVar->getImpl().isArrayLiteralType())
+  if (TypeVar->getImpl().isCollectionLiteralType())
     return !involvesTypeVariables();
 
   // Don't prioritize type variables that don't have any direct bindings.

lib/Sema/TypeCheckConstraints.cpp

@@ -191,8 +191,9 @@ bool TypeVariableType::Implementation::isOpaqueType() const {
   return false;
 }
 
-bool TypeVariableType::Implementation::isArrayLiteralType() const {
-  return locator && locator->directlyAt<ArrayExpr>();
+bool TypeVariableType::Implementation::isCollectionLiteralType() const {
+  return locator && (locator->directlyAt<ArrayExpr>() ||
+                     locator->directlyAt<DictionaryExpr>());
 }
 
 void *operator new(size_t bytes, ConstraintSystem& cs,

test/expr/cast/cf.swift

@@ -105,3 +105,29 @@ func testBridgedCFDowncast(array: [Any], dictionary: [AnyHashable : Any], set: S
   _ = cfDictionary as? [AnyHashable : Any]
   _ = cfSet as? Set<AnyHashable>
 }
+
+func testCastWithImplicitErasure() {
+  enum Info {
+    var id: String { "" }
+    var options: [CFString : Any]? { nil }
+  }
+
+  class Null {}
+
+  struct Test {
+    var flag: Bool = false
+    var info: Info
+
+    func test(key1: CFString!, key2: CFString!, key3: CFString) -> CFDictionary {
+      [
+        key1: flag,
+        key2: info.id,
+        key3: info.options ?? Null()
+        // expected-warning@-1 {{expression implicitly coerced from 'Any?' to 'Any'}}
+        // expected-note@-2 {{provide a default value to avoid this warning}}
+        // expected-note@-3 {{force-unwrap the value to avoid this warning}}
+        // expected-note@-4 {{explicitly cast to 'Any' with 'as Any' to silence this warning}}
+      ] as CFDictionary
+    }
+  }
+}