Move variable into closure

Author: Azoy

stdlib/public/core/KeyPath.swift

@@ -340,8 +340,6 @@ public class KeyPath<Root, Value>: PartialKeyPath<Root> {
       }
     }
 
-    var currentType = rootType
-
     return withBuffer {
       var buffer = $0
 
@@ -380,6 +378,8 @@ public class KeyPath<Root, Value>: PartialKeyPath<Root> {
           $0.initializeElement(at: 0, to: root)
         }
 
+        var currentType = rootType
+
         while true {
           let (rawComponent, optNextType) = buffer.next()
           let newType = optNextType ?? valueType

stdlib/public/core/TemporaryAllocation.swift

@@ -84,7 +84,7 @@ internal func _isStackAllocationSafe(byteCount: Int, alignment: Int) -> Bool {
   // without worrying about running out of space, and the compiler would emit
   // such allocations on the stack anyway when they represent structures or
   // stack-promoted objects.
-  if byteCount <= 1024 {
+  if _fastPath(byteCount <= 1024) {
     return true
   }
 
@@ -178,7 +178,8 @@ internal func _withUnprotectedUnsafeTemporaryAllocation<
   _ body: (Builtin.RawPointer) throws -> R
 ) rethrows -> R {
   // How many bytes do we need to allocate?
-  let byteCount = _byteCountForTemporaryAllocation(of: type, capacity: capacity)
+  //let byteCount = _byteCountForTemporaryAllocation(of: type, capacity: capacity)
+  let byteCount = MemoryLayout<T>.stride &* capacity
 
   guard _isStackAllocationSafe(byteCount: byteCount, alignment: alignment) else {
     return try _fallBackToHeapAllocation(byteCount: byteCount, alignment: alignment, body)
@@ -294,7 +295,7 @@ public func _withUnprotectedUnsafeTemporaryAllocation<R: ~Copyable>(
     alignment: alignment
   ) { pointer in
     let buffer = UnsafeMutableRawBufferPointer(
-      start: .init(pointer),
+      _uncheckedStart: .init(pointer),
       count: byteCount
     )
     return try body(buffer)
@@ -374,7 +375,7 @@ public func _withUnprotectedUnsafeTemporaryAllocation<
   ) { pointer in
     Builtin.bindMemory(pointer, capacity._builtinWordValue, type)
     let buffer = UnsafeMutableBufferPointer<T>(
-      start: .init(pointer),
+      _uncheckedStart: .init(pointer),
       count: capacity
     )
     return try body(buffer)

stdlib/public/core/UnsafeRawBufferPointer.swift.gyb

@@ -116,6 +116,21 @@ public struct Unsafe${Mutable}RawBufferPointer {
     _debugPrecondition(count >= 0, "${Self} with negative count")
     _debugPrecondition(count == 0 || start != nil,
       "${Self} has a nil start and nonzero count")
+
+    self.init(_uncheckedStart: start, count: count)
+  }
+
+  @_alwaysEmitIntoClient
+  internal init(
+    _uncheckedStart start: Unsafe${Mutable}RawPointer?,
+    count: Int
+  ) {
+    _internalInvariant(count >= 0, "${Self} with negative count")
+    _internalInvariant(
+      count == 0 || start != nil,
+      "${Self} has a nil start and nonzero count"
+    )
+
     _position = start
     _end = start.map { $0 + _assumeNonNegative(count) }
   }
@@ -1382,7 +1397,10 @@ public func _withUnprotectedUnsafeBytes<
 #else
   let addr = UnsafeRawPointer(Builtin.addressOfBorrow(value))
 #endif
-  let buffer = UnsafeRawBufferPointer(start: addr, count: MemoryLayout<T>.size)
+  let buffer = UnsafeRawBufferPointer(
+    _uncheckedStart: addr,
+    count: MemoryLayout<T>.size
+  )
   return try body(buffer)
 }