Make ParserSpan noncopyable

Sources/BinaryParsing/Parser Types/ParserSpan.swift

@@ -12,7 +12,7 @@
 /// A non-owning, non-escaping view for parsing binary data.
 ///
 /// You can access a `ParserSpan` from a
-public struct ParserSpan: ~Escapable, BitwiseCopyable {
+public struct ParserSpan: ~Escapable, ~Copyable {
   @usableFromInline
   var _bytes: RawSpan
   @usableFromInline
@@ -29,6 +29,14 @@ public struct ParserSpan: ~Escapable, BitwiseCopyable {
     self._upperBound = _bytes.byteCount
   }
 
+  @inlinable
+  @lifetime(copy other)
+  init(copying other: borrowing ParserSpan) {
+    self._bytes = other._bytes
+    self._lowerBound = other._lowerBound
+    self._upperBound = other._upperBound
+  }
+
   @unsafe
   @inlinable
   @lifetime(borrow buffer)
@@ -91,7 +99,7 @@ extension ParserSpan {
   mutating func divide(at index: Int) -> ParserSpan {
     precondition(index >= _lowerBound)
     precondition(index <= _upperBound)
-    var result = self
+    var result = ParserSpan(copying: self)
     result._upperBound = index
     self._lowerBound = index
     return result
@@ -193,7 +201,7 @@ extension ParserSpan {
     _ body: (inout ParserSpan) throws(E) -> T
   ) throws(E) -> T {
     // Make a mutable copy to perform the work in `body`.
-    var copy = self
+    var copy = ParserSpan(copying: self)
     let result = try body(&copy)
     // `body` didn't throw, so update `self`.
     self = copy

Sources/BinaryParsing/Parser Types/Seeking.swift

@@ -15,7 +15,7 @@ extension ParserSpan {
   public func seeking(toRange range: ParserRange)
     throws(ParsingError) -> ParserSpan
   {
-    var result = self
+    var result = ParserSpan(copying: self)
     try result.seek(toRange: range)
     return result
   }
@@ -25,7 +25,7 @@ extension ParserSpan {
   public func seeking(toRelativeOffset offset: some FixedWidthInteger)
     throws(ParsingError) -> ParserSpan
   {
-    var result = self
+    var result = ParserSpan(copying: self)
     try result.seek(toRelativeOffset: offset)
     return result
   }
@@ -35,7 +35,7 @@ extension ParserSpan {
   public func seeking(toAbsoluteOffset offset: some FixedWidthInteger)
     throws(ParsingError) -> ParserSpan
   {
-    var result = self
+    var result = ParserSpan(copying: self)
     try result.seek(toAbsoluteOffset: offset)
     return result
   }
@@ -45,7 +45,7 @@ extension ParserSpan {
   public func seeking(toOffsetFromEnd offset: some FixedWidthInteger)
     throws(ParsingError) -> ParserSpan
   {
-    var result = self
+    var result = ParserSpan(copying: self)
     try result.seek(toOffsetFromEnd: offset)
     return result
   }

Tests/BinaryParsingTests/SeekingTests.swift

@@ -61,7 +61,7 @@ struct SeekingTests {
 
       // Absolute offset is always referent to original bounds
       var slice1 = try input.sliceSpan(byteCount: 4)
-      var slice2 = slice1
+      var slice2 = try input.seeking(toRange: slice1.parserRange)
       #expect(slice1.startPosition == 2)
       #expect(slice1.count == 4)
 

Tests/BinaryParsingTests/TestingSupport.swift

@@ -14,7 +14,7 @@ import Testing
 
 /// Returns a Boolean value indicating whether two parser spans are identical,
 /// representing the same subregion of the same span of memory.
-func === (lhs: ParserSpan, rhs: ParserSpan) -> Bool {
+func === (lhs: borrowing ParserSpan, rhs: borrowing ParserSpan) -> Bool {
   guard lhs.startPosition == rhs.startPosition,
     lhs.count == rhs.count
   else { return false }