Fix semiregular

Sources/FrontEnd/TypedProgram.swift

@@ -129,7 +129,7 @@ public struct TypedProgram {
   }
 
   /// The type checking of a collection of source files.
-  private final class TypeCheckTask: Operation {
+  private final class TypeCheckTask: Operation, @unchecked Sendable {
 
     /// The sources to check.
     private let sources: [TranslationUnit.ID]

StandardLibrary/Sources/Array.hylo

@@ -1,5 +1,5 @@
 /// An ordered, random-access collection.
-public type Array<Element: SemiRegular>: SemiRegular {
+public type Array<Element: Movable & Deinitializable>: Movable, Deinitializable {
 
   /// The out-of-line storage of the array.
   ///
@@ -207,7 +207,7 @@ public type Array<Element: SemiRegular>: SemiRegular {
 
 }
 
-public conformance Array: Equatable {
+public conformance Array: Equatable where Element: Equatable {
 
   /// Returns `true` iff `other` has an equivalent value.
   public fun infix== (_ other: Self) -> Bool {

StandardLibrary/Sources/Core/Range.hylo

@@ -1,5 +1,5 @@
 /// A half-open interval from a lower bound up to, but not including, an uppor bound.
-public type Range<Bound: SemiRegular & Comparable> {
+public type Range<Bound: Movable & Deinitializable & Comparable> {
 
   // TODO: private(set)
   /// The minimum value included in `self`.

StandardLibrary/Sources/Core/Regular.hylo

@@ -3,9 +3,9 @@
 ///
 /// - Move is value-preserving.
 /// - Destruction has no side-effects.
-public trait SemiRegular: Deinitializable, Movable, Equatable {}
+public trait SemiRegular: Copyable, Deinitializable {}
 
 /// Regular types (roughly per Stepanov).
 ///
 /// Copies have equal value.
-public trait Regular: SemiRegular, Copyable {}
+public trait Regular: SemiRegular, Equatable {}

Tests/HyloTests/TestCases/TypeChecking/AbstractType.hylo

@@ -1,14 +1,19 @@
 //- typeCheck expecting: .success
 
-trait P: SemiRegular {
-  type T: SemiRegular
-  type U: SemiRegular
+// Our SemiRegular when this test was written wasn't the genuine
+// SemiRegular but was being depended on by this test, so rephrasing
+// it here.
+trait LegacySemiRegular: Deinitializable, Movable, Equatable {}
+
+trait P: LegacySemiRegular {
+  type T: LegacySemiRegular
+  type U: LegacySemiRegular
 
   fun t(_ x: T)
   fun u(_ x: U)
 }
 
-trait Q: SemiRegular {
+trait Q: LegacySemiRegular {
   type V: P
   property v: V { let }
 }