Updated primitive value unwrapping to enable static type optimizations during compilation

This should be faster than the previous case, since the compiler should be able to optimize the switch away when it inlines the function for a specific generic type.

Author: dimitribouniol

Sources/DynamicCodable/CoderInternals.swift

@@ -71,30 +71,28 @@ extension DynamicCodable {
 
     @inline(__always)
     func unwrap<T>(errorHandler: () throws -> Never) rethrows -> T {
-        let value: Any
-        
-        switch self {
-        case .keyed(let keyed):     value = keyed
-        case .unkeyed(let unkeyed): value = unkeyed
-        case .nil:                  value = Nil.none as Any
-        case .bool(let bool):       value = bool
-        case .string(let string):   value = string
-        case .float64(let float64): value = float64
-        case .float32(let float32): value = float32
-        case .int(let int):         value = int
-        case .int8(let int8):       value = int8
-        case .int16(let int16):     value = int16
-        case .int32(let int32):     value = int32
-        case .int64(let int64):     value = int64
-        case .uint(let uint):       value = uint
-        case .uint8(let uint8):     value = uint8
-        case .uint16(let uint16):   value = uint16
-        case .uint32(let uint32):   value = uint32
-        case .uint64(let uint64):   value = uint64
-        case .empty:                value = ()
+        switch T.self {
+        case is Keyed.Type:     if case .keyed(let keyed) = self        { return unsafeBitCast(keyed,       to: T.self) }
+        case is Unkeyed.Type:   if case .unkeyed(let unkeyed) = self    { return unsafeBitCast(unkeyed,     to: T.self) }
+        case is Nil.Type:       if case .nil = self                     { return unsafeBitCast(Nil.none,    to: T.self) }
+        case is Bool.Type:      if case .bool(let bool) = self          { return unsafeBitCast(bool,        to: T.self) }
+        case is String.Type:    if case .string(let string) = self      { return unsafeBitCast(string,      to: T.self) }
+        case is Float64.Type:   if case .float64(let float64) = self    { return unsafeBitCast(float64,     to: T.self) }
+        case is Float32.Type:   if case .float64(let float32) = self    { return unsafeBitCast(float32,     to: T.self) }
+        case is Int.Type:       if case .int(let int) = self            { return unsafeBitCast(int,         to: T.self) }
+        case is Int8.Type:      if case .int8(let int8) = self          { return unsafeBitCast(int8,        to: T.self) }
+        case is Int16.Type:     if case .int16(let int16) = self        { return unsafeBitCast(int16,       to: T.self) }
+        case is Int32.Type:     if case .int32(let int32) = self        { return unsafeBitCast(int32,       to: T.self) }
+        case is Int64.Type:     if case .int64(let int64) = self        { return unsafeBitCast(int64,       to: T.self) }
+        case is UInt.Type:      if case .uint(let uint) = self          { return unsafeBitCast(uint,        to: T.self) }
+        case is UInt8.Type:     if case .uint8(let uint8) = self        { return unsafeBitCast(uint8,       to: T.self) }
+        case is UInt16.Type:    if case .uint16(let uint16) = self      { return unsafeBitCast(uint16,      to: T.self) }
+        case is UInt32.Type:    if case .uint32(let uint32) = self      { return unsafeBitCast(uint32,      to: T.self) }
+        case is UInt64.Type:    if case .uint64(let uint64) = self      { return unsafeBitCast(uint64,      to: T.self) }
+        case is Empty.Type:     if case .empty = self                   { return unsafeBitCast((),          to: T.self) }
+        default: break // TODO: We should do something different here, so we can ignore this case in the caller. Perhaps return a specialized error?
         }
 
-        guard let value = value as? T else { try errorHandler() }
-        return value
+        try errorHandler()
     }
 }