Merge pull request swiftlang#80501 from tshortli/stdlib-warnings

stdlib: Address #StrictMemorySafety and unreachable code warnings

Author: tshortli

stdlib/public/core/StringBridge.swift

@@ -119,7 +119,7 @@ private func _stdlib_binary_createIndirectTaggedPointerNSString(
   ptr: UnsafePointer<UInt8>,
   count: Int
 ) -> UnsafeRawPointer? {
-  return _swift_stdlib_CreateIndirectTaggedPointerString(ptr, count);
+  return unsafe _swift_stdlib_CreateIndirectTaggedPointerString(ptr, count);
 }
 
 @usableFromInline // @testable
@@ -631,12 +631,12 @@ extension String {
     }
     if _guts._object.isImmortal && !_guts._object.largeFastIsConstantCocoa {
       if _guts.isASCII && _guts._object.isFastZeroTerminated {
-        let ptr = _guts._object.fastUTF8.baseAddress!
+        let ptr = unsafe _guts._object.fastUTF8.baseAddress!
         let count = _guts.count
-        if let indirect = _stdlib_binary_createIndirectTaggedPointerNSString(
+        if let indirect = unsafe _stdlib_binary_createIndirectTaggedPointerNSString(
           ptr: ptr, count: count
         ) {
-          return unsafeBitCast(indirect, to: AnyObject.self)
+          return unsafe unsafeBitCast(indirect, to: AnyObject.self)
         }
       }
       let gutsCountAndFlags = _guts._object._countAndFlags

stdlib/public/core/StringUTF8View.swift

@@ -345,11 +345,11 @@ extension String.UTF8View {
 #endif
       let count = _guts.count
       if _guts.isSmall {
-        let a = Builtin.addressOfBorrow(self)
-        let address = unsafe UnsafePointer<UTF8.CodeUnit>(a)
-        let span = unsafe Span(_unsafeStart: address, count: count)
         fatalError("Span over the small string form is not supported yet.")
-        return unsafe _overrideLifetime(span, borrowing: self)
+//        let a = Builtin.addressOfBorrow(self)
+//        let address = unsafe UnsafePointer<UTF8.CodeUnit>(a)
+//        let span = unsafe Span(_unsafeStart: address, count: count)
+//        return unsafe _overrideLifetime(span, borrowing: self)
       }
       _precondition(_guts.isFastUTF8)
       let buffer = unsafe _guts._object.fastUTF8

stdlib/public/core/Substring.swift

@@ -782,19 +782,19 @@ extension Substring.UTF8View {
         let base: String.UTF8View = self._base
         let first = base._foreignDistance(from: base.startIndex, to: startIndex)
         let count = base._foreignDistance(from: startIndex, to: endIndex)
-        let span = unsafe base.span._extracting(first..<(first &+ count))
+        let span = base.span._extracting(first..<(first &+ count))
         return unsafe _overrideLifetime(span, borrowing: self)
       }
 #endif
       let first = _slice._startIndex._encodedOffset
       let end = _slice._endIndex._encodedOffset
       if _wholeGuts.isSmall {
-        let a = Builtin.addressOfBorrow(self)
-        let offset = first &+ (2 &* MemoryLayout<String.Index>.stride)
-        let start = unsafe UnsafePointer<UTF8.CodeUnit>(a).advanced(by: offset)
-        let span = unsafe Span(_unsafeStart: start, count: end &- first)
         fatalError("Span over the small string form is not supported yet.")
-        return unsafe _overrideLifetime(span, borrowing: self)
+//        let a = Builtin.addressOfBorrow(self)
+//        let offset = first &+ (2 &* MemoryLayout<String.Index>.stride)
+//        let start = unsafe UnsafePointer<UTF8.CodeUnit>(a).advanced(by: offset)
+//        let span = unsafe Span(_unsafeStart: start, count: end &- first)
+//        return unsafe _overrideLifetime(span, borrowing: self)
       }
       _internalInvariant(_wholeGuts.isFastUTF8)
       var span = unsafe Span(_unsafeElements: _wholeGuts._object.fastUTF8)