Merge pull request #10955 from Philippus/align-opaque-type-aliases-code

Align Opaque Type Aliases code with docs

Author: odersky

tests/neg/opaque-bounds.scala

@@ -19,16 +19,20 @@ object Access {
  opaque type PermissionChoice = Int
  opaque type Permission <: Permissions & PermissionChoice = Int
 
- extension (x: Permissions) def & (y: Permissions): Permissions = x & y
- extension (x: PermissionChoice) def | (y: PermissionChoice): PermissionChoice = x | y
- extension (x: Permissions) def is(y: Permissions) = (x & y) == y
- extension (x: Permissions) def isOneOf(y: PermissionChoice) = (x & y) != 0
+ extension (x: Permissions)
+ def & (y: Permissions): Permissions = x | y
+ extension (x: PermissionChoice)
+ def | (y: PermissionChoice): PermissionChoice = x | y
+ extension (granted: Permissions)
+ def is(required: Permissions) = (granted & required) == required
+ extension (granted: Permissions)
+ def isOneOf(required: PermissionChoice) = (granted & required) != 0
 
  val NoPermission: Permission = 0
- val ReadOnly: Permission = 1
- val WriteOnly: Permission = 2
- val ReadWrite: Permissions = ReadOnly & WriteOnly
- val ReadOrWrite: PermissionChoice = ReadOnly | WriteOnly
+ val Read: Permission = 1
+ val Write: Permission = 2
+ val ReadWrite: Permissions = Read | Write
+ val ReadOrWrite: PermissionChoice = Read | Write
 }
 
 object User {
@@ -39,7 +43,7 @@ object User {
  val p1: Permissions = ReadOrWrite // error
  val p2: PermissionChoice = ReadWrite // error
 
- val x = Item(ReadOnly)
+ val x = Item(Read)
 
  assert( x.rights.is(ReadWrite) == false )
  assert( x.rights.isOneOf(ReadOrWrite) == true )

tests/neg/opaque.scala

@@ -43,7 +43,7 @@ object logs {
  // This is the second way to unlift the logarithm type
  def toDouble: Double = math.exp(`this`)
  def +(that: Logarithm): Logarithm = Logarithm(math.exp(`this`) + math.exp(that))
- def *(that: Logarithm): Logarithm = Logarithm(`this` + that)
+ def *(that: Logarithm): Logarithm = `this` + that
  }
  }
 }

tests/pos/reference/opaque.scala

@@ -12,11 +12,10 @@ object Logarithms {
  }
 
  // Extension methods define opaque types' public APIs
- extension (x: Logarithm) {
+ extension (x: Logarithm)
  def toDouble: Double = math.exp(x)
  def + (y: Logarithm): Logarithm = Logarithm(math.exp(x) + math.exp(y))
- def * (y: Logarithm): Logarithm = Logarithm(x + y)
- }
+ def * (y: Logarithm): Logarithm = x + y
 }
 
 object LogTest {
@@ -36,31 +35,42 @@ object Access {
  opaque type PermissionChoice = Int
  opaque type Permission <: Permissions & PermissionChoice = Int
 
- extension (x: Permissions) def & (y: Permissions): Permissions = x & y
- extension (x: PermissionChoice) def | (y: PermissionChoice): PermissionChoice = x | y
- extension (x: Permissions) def is(y: Permissions) = (x & y) == y
- extension (x: Permissions) def isOneOf(y: PermissionChoice) = (x & y) != 0
+ extension (x: Permissions)
+ def & (y: Permissions): Permissions = x | y
+ extension (x: PermissionChoice)
+ def | (y: PermissionChoice): PermissionChoice = x | y
+ extension (granted: Permissions)
+ def is(required: Permissions) = (granted & required) == required
+ extension (granted: Permissions)
+ def isOneOf(required: PermissionChoice) = (granted & required) != 0
 
  val NoPermission: Permission = 0
- val ReadOnly: Permission = 1
- val WriteOnly: Permission = 2
- val ReadWrite: Permissions = ReadOnly & WriteOnly
- val ReadOrWrite: PermissionChoice = ReadOnly | WriteOnly
+ val Read: Permission = 1
+ val Write: Permission = 2
+ val ReadWrite: Permissions = Read | Write
+ val ReadOrWrite: PermissionChoice = Read | Write
 }
 
 object User {
  import Access._
 
  case class Item(rights: Permissions)
 
- val x = Item(ReadOnly) // OK, since Permission <: Permissions
+ val roItem = Item(Read) // OK, since Permission <: Permissions
+ val rwItem = Item(ReadWrite)
+ val noItem = Item(NoPermission)
 
- assert( x.rights.is(ReadWrite) == false )
- assert( x.rights.isOneOf(ReadOrWrite) == true )
+ assert( roItem.rights.is(ReadWrite) == false )
+ assert( roItem.rights.isOneOf(ReadOrWrite) == true )
 
- // Would be a type error:
- // assert( x.rights.isOneOf(ReadWrite) == true )
+ assert( rwItem.rights.is(ReadWrite) == true )
+ assert( rwItem.rights.isOneOf(ReadOrWrite) == true )
 
+ assert( noItem.rights.is(ReadWrite) == false )
+ assert( noItem.rights.isOneOf(ReadOrWrite) == false )
+
+ // Would be a type error:
+ // assert( roItem.rights.isOneOf(ReadWrite) == true )
 }
 
 object o {