Merge pull request #1565 from hylo-lang/synthetic-none-equal

Remove needless custom implementation of `None.infix==`

Sources/FrontEnd/TypeChecking/TypeChecker.swift

@@ -4434,9 +4434,16 @@ struct TypeChecker {
     // `X` from the resolution of the qualification and `Y` from the resolution of the candidate.
     entityType = specialize(entityType, for: specialization, in: scopeOfUse)
 
+    // If `d` is a trait requirement, we have to remember the generic arguments that are part of
+    // its qualification in case its implementation is synthesized. Otherwise, we should only
+    // remember arguments to parameters that are in `d`'s scope.
     var capturedArguments = GenericArguments.empty
-    for p in capturedGenericParameter(of: d) {
-      capturedArguments[p] = specialization[p]
+    if program.isRequirement(d) {
+      capturedArguments = specialization
+    } else {
+      for p in capturedGenericParameter(of: d) {
+        capturedArguments[p] = specialization[p]
+      }
     }
 
     return (entityType, capturedArguments, isConstructor)

StandardLibrary/Sources/Core/Optional.hylo

@@ -9,11 +9,6 @@ public type None<T>: Regular {
   /// Creates a value denoting the absence of an instance of `T`.
   public memberwise init
 
-  // TODO: Remove when #1078 is implemented.
-  public fun infix==(_ other: Self) -> Bool {
-    true
-  }
-
 }
 
 public extension Optional {

Tests/LibraryTests/TestCases/OptionalTests.hylo

@@ -1,6 +1,8 @@
 //- compileAndRun expecting: .success
 
 public fun main() {
+  precondition(None<Int>() == None<Int>())
+
   var x = 42 as Optional<Int>
   let y = if let i: Int = x { i.copy() } else { 0 }
   precondition(y == 42)