From 645cbea2f0ac8c16f2cf349473ac2f759601d796 Mon Sep 17 00:00:00 2001
From: Max Desiatov <max@desiatov.com>
Date: Sat, 19 Feb 2022 11:06:38 +0000
Subject: [PATCH 1/3] Add `OpaquePointer` implementation

---
 Sources/Core/OpaquePointer.swift | 48 ++++++++++++++++++++++++++++++++
 1 file changed, 48 insertions(+)
 create mode 100644 Sources/Core/OpaquePointer.swift

diff --git a/Sources/Core/OpaquePointer.swift b/Sources/Core/OpaquePointer.swift
new file mode 100644
index 0000000..9f22fec
--- /dev/null
+++ b/Sources/Core/OpaquePointer.swift
@@ -0,0 +1,48 @@
+// Copyright © 2022 Max Desiatov <max@desiatov.com>.
+// All Rights Reserved.
+// SPDX-License-Identifier: BSD-3
+
+@frozen
+public struct OpaquePointer {
+  @usableFromInline
+  internal var _rawValue: Builtin.RawPointer
+
+  @usableFromInline @_transparent
+  internal init(_ v: Builtin.RawPointer) {
+    _rawValue = v
+  }
+
+  @_transparent
+  public init?(bitPattern: Int) {
+    guard bitPattern != 0 else { return nil }
+    _rawValue = Builtin.inttoptr_Word(bitPattern._value)
+  }
+
+  @_transparent
+  public init?(bitPattern: UInt) {
+    guard bitPattern != 0 else { return nil }
+    _rawValue = Builtin.inttoptr_Word(bitPattern._value)
+  }
+
+  @_transparent
+  public init<T>(@_nonEphemeral _ from: UnsafePointer<T>) {
+    _rawValue = from._rawValue
+  }
+
+  @_transparent
+  public init?<T>(@_nonEphemeral _ from: UnsafePointer<T>?) {
+    guard let unwrapped = from else { return nil }
+    self.init(unwrapped)
+  }
+
+  @_transparent
+  public init<T>(@_nonEphemeral _ from: UnsafeMutablePointer<T>) {
+    _rawValue = from._rawValue
+  }
+
+  @_transparent
+  public init?<T>(@_nonEphemeral _ from: UnsafeMutablePointer<T>?) {
+    guard let unwrapped = from else { return nil }
+    self.init(unwrapped)
+  }
+}

From 5f4eff0b28b22f4850d208487a866a97b18c49bf Mon Sep 17 00:00:00 2001
From: Max Desiatov <max@desiatov.com>
Date: Sat, 19 Feb 2022 11:20:13 +0000
Subject: [PATCH 2/3] Add `OpaquePointer.swift` to `CMakeLists.txt`

---
 Sources/Core/CMakeLists.txt | 1 +
 Sources/Core/Int.swift      | 3 +--
 Sources/Core/UInt.swift     | 3 +--
 3 files changed, 3 insertions(+), 4 deletions(-)

diff --git a/Sources/Core/CMakeLists.txt b/Sources/Core/CMakeLists.txt
index a09687e..ae1806d 100644
--- a/Sources/Core/CMakeLists.txt
+++ b/Sources/Core/CMakeLists.txt
@@ -15,6 +15,7 @@ add_library(swiftCore
   Int32.swift
   Integers.swift
   Never.swift
+  OpaquePointer.swift
   Optional.swift
   OptionSet.swift
   Policy.swift
diff --git a/Sources/Core/Int.swift b/Sources/Core/Int.swift
index e357970..bafa752 100644
--- a/Sources/Core/Int.swift
+++ b/Sources/Core/Int.swift
@@ -15,8 +15,7 @@ extension Int: _ExpressibleByBuiltinIntegerLiteral {
   }
 }
 
-extension Int: ExpressibleByIntegerLiteral {
-}
+extension Int: ExpressibleByIntegerLiteral {}
 
 extension Int: Equatable {
   @_transparent
diff --git a/Sources/Core/UInt.swift b/Sources/Core/UInt.swift
index 45fff3b..57cfd9e 100644
--- a/Sources/Core/UInt.swift
+++ b/Sources/Core/UInt.swift
@@ -15,8 +15,7 @@ extension UInt: _ExpressibleByBuiltinIntegerLiteral {
   }
 }
 
-extension UInt: ExpressibleByIntegerLiteral {
-}
+extension UInt: ExpressibleByIntegerLiteral {}
 
 extension UInt: Equatable {
   @_transparent

From f324ab293785ee49e1fb02026d6dff9b622543ae Mon Sep 17 00:00:00 2001
From: Max Desiatov <max@desiatov.com>
Date: Sat, 19 Feb 2022 11:34:01 +0000
Subject: [PATCH 3/3] Exclude failing 5.4 and 5.5 in `OpaquePointer`

---
 Sources/Core/Int.swift           | 3 ++-
 Sources/Core/OpaquePointer.swift | 9 +++++++--
 Sources/Core/UInt.swift          | 3 ++-
 3 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/Sources/Core/Int.swift b/Sources/Core/Int.swift
index bafa752..e357970 100644
--- a/Sources/Core/Int.swift
+++ b/Sources/Core/Int.swift
@@ -15,7 +15,8 @@ extension Int: _ExpressibleByBuiltinIntegerLiteral {
   }
 }
 
-extension Int: ExpressibleByIntegerLiteral {}
+extension Int: ExpressibleByIntegerLiteral {
+}
 
 extension Int: Equatable {
   @_transparent
diff --git a/Sources/Core/OpaquePointer.swift b/Sources/Core/OpaquePointer.swift
index 9f22fec..8744a2b 100644
--- a/Sources/Core/OpaquePointer.swift
+++ b/Sources/Core/OpaquePointer.swift
@@ -2,6 +2,9 @@
 // All Rights Reserved.
 // SPDX-License-Identifier: BSD-3
 
+// This `OpaquePointer` implementation is known to crash 5.4 and 5.5 compiler releases on Windows.
+#if swift(>=5.6)
+
 @frozen
 public struct OpaquePointer {
   @usableFromInline
@@ -14,13 +17,13 @@ public struct OpaquePointer {
 
   @_transparent
   public init?(bitPattern: Int) {
-    guard bitPattern != 0 else { return nil }
+    if bitPattern == 0 { return nil }
     _rawValue = Builtin.inttoptr_Word(bitPattern._value)
   }
 
   @_transparent
   public init?(bitPattern: UInt) {
-    guard bitPattern != 0 else { return nil }
+    if bitPattern == 0 { return nil }
     _rawValue = Builtin.inttoptr_Word(bitPattern._value)
   }
 
@@ -46,3 +49,5 @@ public struct OpaquePointer {
     self.init(unwrapped)
   }
 }
+
+#endif
diff --git a/Sources/Core/UInt.swift b/Sources/Core/UInt.swift
index 57cfd9e..45fff3b 100644
--- a/Sources/Core/UInt.swift
+++ b/Sources/Core/UInt.swift
@@ -15,7 +15,8 @@ extension UInt: _ExpressibleByBuiltinIntegerLiteral {
   }
 }
 
-extension UInt: ExpressibleByIntegerLiteral {}
+extension UInt: ExpressibleByIntegerLiteral {
+}
 
 extension UInt: Equatable {
   @_transparent