Update tests and docs to new extension syntax

Author: odersky

compiler/src/dotty/tools/dotc/typer/Inferencing.scala

@@ -530,7 +530,7 @@ trait Inferencing { this: Typer =>
          *  is in i7558.scala:
          *
          *      type Tr[+V1, +O1 <: V1]
-         *      def [V2, O2 <: V2](tr: Tr[V2, O2]) sl: Tr[V2, O2] = ???
+         *      extension [V2, O2 <: V2](tr: Tr[V2, O2]) def sl: Tr[V2, O2] = ???
          *      def as[V3, O3 <: V3](tr: Tr[V3, O3]) : Tr[V3, O3] = tr.sl
          *
          *   Here we interpolate at some point V2 and O2 given the constraint

docs/docs/contributing/debugging.md

@@ -88,7 +88,7 @@ But you can also do:
 assertPositioned(tree.reporting(s"Tree is: $result"))
 ```
 
-`def (a: A).reporting(f: WrappedResult[T] ?=> String, p: Printer = Printers.default): A` is defined on all types. The function `f` can be written without the argument since it is a context function`. The `result` variable is a part of the `WrapperResult` – a tiny framework powering the `reporting` function. Basically, whenever you are using `reporting` on an object `A`, you can use the `result: A` variable from this function and it will be equal to the object you are calling `reporting` on.
+`extension (a: A) def reporting(f: WrappedResult[T] ?=> String, p: Printer = Printers.default): A` is defined on all types. The function `f` can be written without the argument since it is a context function`. The `result` variable is a part of the `WrapperResult` – a tiny framework powering the `reporting` function. Basically, whenever you are using `reporting` on an object `A`, you can use the `result: A` variable from this function and it will be equal to the object you are calling `reporting` on.
 
 ## Printing out trees after phases
 To print out the trees you are compiling after the FrontEnd (scanner, parser, namer, typer) phases:

docs/docs/reference/contextual/context-functions.md

@@ -16,7 +16,7 @@ the same way methods with context parameters are applied. For instance:
   given ec as ExecutionContext = ...
 
   def f(x: Int): ExecutionContext ?=> Int = ...
-  
+
   // could be written as follows with the type alias from above
   // def f(x: Int): Executable[Int] = ...
 
@@ -125,7 +125,7 @@ object PostConditions {
 
   def result[T](using r: WrappedResult[T]): T = r
 
-  def [T] (x: T).ensuring(condition: WrappedResult[T] ?=> Boolean): T = {
+  extension [T](x: T) def ensuring(condition: WrappedResult[T] ?=> Boolean): T = {
     assert(condition(using x))
     x
   }

docs/docs/reference/contextual/derivation-macro.md

@@ -120,7 +120,8 @@ Alternatively and what is shown below is that we can call the `eqv` method
 directly. The `eqGen` can trigger the derivation.
 
 ```scala
-inline def [T](x: =>T) === (y: =>T)(using eq: Eq[T]): Boolean = eq.eqv(x, y)
+extension [T](x: =>T)
+  inline def === (y: =>T)(using eq: Eq[T]): Boolean = eq.eqv(x, y)
 
 implicit inline def eqGen[T]: Eq[T] = ${ Eq.derived[T] }
 ```
@@ -216,7 +217,8 @@ object Eq {
 }
 
 object Macro3 {
-  inline def [T](x: =>T) === (y: =>T)(using eq: Eq[T]): Boolean = eq.eqv(x, y)
+  extension [T](x: =>T)
+    inline def === (y: =>T)(using eq: Eq[T]): Boolean = eq.eqv(x, y)
 
   implicit inline def eqGen[T]: Eq[T] = ${ Eq.derived[T] }
 }

docs/docs/reference/contextual/givens.md

@@ -9,8 +9,8 @@ that serve for synthesizing arguments to [context parameters](./using-clauses.ht
 ```scala
 trait Ord[T] {
   def compare(x: T, y: T): Int
-  def (x: T) < (y: T) = compare(x, y) < 0
-  def (x: T) > (y: T) = compare(x, y) > 0
+  extension (x: T) def < (y: T) = compare(x, y) < 0
+  extension (x: T) def > (y: T) = compare(x, y) > 0
 }
 
 given intOrd as Ord[Int] {

docs/docs/reference/contextual/relationship-implicits.md

@@ -111,7 +111,7 @@ will map to with clauses instead.
 
 Extension methods have no direct counterpart in Scala 2, but they can be simulated with implicit classes. For instance, the extension method
 ```scala
-def (c: Circle).circumference: Double = c.radius * math.Pi * 2
+extension (c: Circle) def circumference: Double = c.radius * math.Pi * 2
 ```
 could be simulated to some degree by
 ```scala

docs/docs/reference/contextual/type-classes.md

@@ -156,7 +156,7 @@ A `List` can be turned into a monad via this `given` instance:
 given listMonad as Monad[List]:
   def pure[A](x: A): List[A] =
     List(x)
-  extension def [A, B](xs: List[A])
+  extension [A, B](xs: List[A])
     def flatMap(f: A => List[B]): List[B] =
       xs.flatMap(f) // rely on the existing `flatMap` method of `List`
 ```

docs/docs/reference/dropped-features/package-objects.md

@@ -22,7 +22,7 @@ def b = a._2
 case class C()
 
 implicit object Cops {
-  def (x: C).pair(y: C) = (x, y)
+  extension (x: C) def pair(y: C) = (x, y)
 }
 ```
 There may be several source files in a package containing such toplevel definitions, and source files can freely mix toplevel value, method, and type definitions with classes and objects.

docs/docs/reference/metaprogramming/macros.md

@@ -717,7 +717,7 @@ This might be used to then perform an implicit search as in:
 
 
 ```scala
-inline def (inline sc: StringContext).showMe(inline args: Any*): String = ${ showMeExpr('sc, 'args) }
+extension (inline sc: StringContext) inline def showMe(inline args: Any*): String = ${ showMeExpr('sc, 'args) }
 
 private def showMeExpr(sc: Expr[StringContext], argsExpr: Expr[Seq[Any]])(using QuoteContext): Expr[String] = {
   argsExpr match {

docs/docs/reference/other-new-features/opaques.md

@@ -29,15 +29,15 @@ object Logarithms {
 }
 ```
 
-This introduces `Logarithm` as a new abstract type, which is implemented as `Double`. 
+This introduces `Logarithm` as a new abstract type, which is implemented as `Double`.
 The fact that `Logarithm` is the same as `Double` is only known in the scope where
 `Logarithm` is defined which in the above example corresponds to the object `Logarithms`.
-Or in other words, within the scope it is treated as type alias, but this is opaque to the outside world 
+Or in other words, within the scope it is treated as type alias, but this is opaque to the outside world
 where in consequence `Logarithm` is seen as an abstract type and has nothing to do with `Double`.
 
-The public API of `Logarithm` consists of the `apply` and `safe` methods defined in the companion object. 
+The public API of `Logarithm` consists of the `apply` and `safe` methods defined in the companion object.
 They convert from `Double`s to `Logarithm` values. Moreover, a collective extension `logarithmOps` provides the extension methods `toDouble` that converts the other way,
-and operations `+` and `*` on `Logarithm` values. 
+and operations `+` and `*` on `Logarithm` values.
 The following operations would be valid because they use functionality implemented in the `Logarithms` object.
 
 ```scala
@@ -68,10 +68,10 @@ object Access {
   opaque type PermissionChoice = Int
   opaque type Permission <: Permissions & PermissionChoice = Int
 
-  def (x: Permissions) & (y: Permissions): Permissions = x | y
-  def (x: PermissionChoice) | (y: PermissionChoice): PermissionChoice = x | y
-  def (granted: Permissions).is(required: Permissions) = (granted & required) == required
-  def (granted: Permissions).isOneOf(required: PermissionChoice) = (granted & required) != 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 Read: Permission = 1

docs/docs/reference/other-new-features/quoted-pattern-spec.md

@@ -46,11 +46,11 @@ type Env
 def notMatched = None
 def matched = Some(()) // aka Some(Tuple0())
 def matched[T](x: T) = Some(Tuple1(x))
-def (x: Matching) && (y: Matching) = if (x == None || y == None) None else Some(x.get ++ y.get)
+extension (x: Matching) def && (y: Matching) = if (x == None || y == None) None else Some(x.get ++ y.get)
 def fold[T](m: Mattching*)(using Env): Matching = m.fold(matched)(_ && _)
 
 // `a =#= b` stands for `a` matches `b`
-def (scrutinee: Tree) =#= pattern: Tree)(using Env): Matching // described by cases in the tables below
+extension (scrutinee: Tree) def =#= pattern: Tree)(using Env): Matching // described by cases in the tables below
 
 def envWith(equiv: (Symbol, Symbol)*)(using Env): Env // Adds to the current environment the fact that s1 from the scrutinee is equivalent to s2 in the pattern
 

docs/docs/reference/other-new-features/tupled-function.md

@@ -44,7 +44,8 @@ The following defines `tupled` as [extension method](../contextual/extension-met
  *  @tparam Args the tuple type with the same types as the function arguments of F
  *  @tparam R the return type of F
  */
-def [F, Args <: Tuple, R](f: F).tupled(using tf: TupledFunction[F, Args => R]): Args => R = tf.tupled(f)
+extension [F, Args <: Tuple, R](f: F)
+  def tupled(using tf: TupledFunction[F, Args => R]): Args => R = tf.tupled(f)
 ```
 
 `TupledFunction` can be used to generalize the `Function.untupled` to a function of any arities ([full example](https://github.com/lampepfl/dotty/blob/master/tests/run/tupled-function-untupled.scala))
@@ -59,7 +60,8 @@ def [F, Args <: Tuple, R](f: F).tupled(using tf: TupledFunction[F, Args => R]):
  *  @tparam Args the tuple type with the same types as the function arguments of F
  *  @tparam R the return type of F
  */
-def [F, Args <: Tuple, R](f: Args => R).untupled(using tf: TupledFunction[F, Args => R]): F = tf.untupled(f)
+extension [F, Args <: Tuple, R](f: Args => R)
+  def untupled(using tf: TupledFunction[F, Args => R]): F = tf.untupled(f)
 ```
 
 `TupledFunction` can also be used to generalize the [`Tuple1.compose`](https://github.com/lampepfl/dotty/blob/master/tests/run/tupled-function-compose.scala) and [`Tuple1.andThen`](https://github.com/lampepfl/dotty/blob/master/tests/run/tupled-function-andThen.scala) methods to compose functions of larger arities and with functions that return tuples.
@@ -73,7 +75,8 @@ def [F, Args <: Tuple, R](f: Args => R).untupled(using tf: TupledFunction[F, Arg
  *  @tparam GArgs the tuple type with the same types as the function arguments of G
  *  @tparam R the return type of F
  */
-def [F, G, FArgs <: Tuple, GArgs <: Tuple, R](f: F).compose(g: G)(using tg: TupledFunction[G, GArgs => FArgs], tf: TupledFunction[F, FArgs => R]): GArgs => R = {
+extension [F, G, FArgs <: Tuple, GArgs <: Tuple, R](f: F)
+  def compose(g: G)(using tg: TupledFunction[G, GArgs => FArgs], tf: TupledFunction[F, FArgs => R]): GArgs => R = {
   (x: GArgs) => tf.tupled(f)(tg.tupled(g)(x))
 }
 ```

tests/init/crash/i5606.scala

@@ -1,6 +1,6 @@
 object Test extends App {
 
-  def [A, B](f: A => B) `$` (a: A): B = f(a)
+  extension [A, B](f: A => B) def `$` (a: A): B = f(a)
 
   assert((((a: Int) => a.toString()) `$` 10) == "10")
 

tests/init/crash/i7821.scala

@@ -4,7 +4,7 @@ object XObject {
   def anX: X = 5
 
   given ops as Object {
-    def (x: X) + (y: X): X = x + y
+    extension (x: X) def + (y: X): X = x + y
   }
 }
 
@@ -14,7 +14,7 @@ object MyXObject {
   def anX: MyX = XObject.anX
 
   given ops as Object {
-    def (x: MyX) + (y: MyX): MyX = x + y // error: warring: Infinite recursive call
+    extension (x: MyX) def + (y: MyX): MyX = x + y // error: warring: Infinite recursive call
   }
 }
 

tests/neg-custom-args/fatal-warnings/i7821.scala

@@ -4,7 +4,7 @@ object XObject {
   def anX: X = 5
 
   given ops as Object {
-    def (x: X) + (y: X): X = x + y
+    extension (x: X) def + (y: X): X = x + y
   }
 }
 
@@ -14,7 +14,7 @@ object MyXObject {
   def anX: MyX = XObject.anX
 
   given ops as Object {
-    def (x: MyX) + (y: MyX): MyX = x + y // error: warring: Infinite recursive call
+    extension (x: MyX) def + (y: MyX): MyX = x + y // error: warring: Infinite recursive call
   }
 }
 

tests/neg-custom-args/infix.scala

@@ -8,9 +8,9 @@ class C:
 
 object C:
   given AnyRef:
-    def (x: C) iop (y: Int) = ???
-    def (x: C).mop (y: Int) = ???
-    def (x: C) ++ (y: Int) = ???
+    extension (x: C) @infix def iop (y: Int) = ???
+    extension (x: C) def mop (y: Int) = ???
+    extension (x: C) def ++ (y: Int) = ???
 
 val c = C()
 def test() = {

tests/neg-macros/i6432/Macro_1.scala

@@ -4,7 +4,7 @@ import scala.quoted.autolift
 
 
 object Macro {
-  inline def (inline sc: StringContext).foo(args: String*): Unit = ${ impl('sc) }
+  extension (inline sc: StringContext) inline def foo(args: String*): Unit = ${ impl('sc) }
 
   def impl(sc: Expr[StringContext])(using qctx: QuoteContext) : Expr[Unit] = {
     import qctx.tasty._

tests/neg-macros/i6432b/Macro_1.scala

@@ -4,7 +4,7 @@ import scala.quoted.autolift
 
 
 object Macro {
-  inline def (inline sc: StringContext).foo(args: String*): Unit = ${ impl('sc) }
+  extension (inline sc: StringContext) inline def foo(args: String*): Unit = ${ impl('sc) }
 
   def impl(sc: Expr[StringContext])(using qctx: QuoteContext) : Expr[Unit] = {
     import qctx.tasty._

tests/neg-macros/i7698.scala

@@ -10,4 +10,4 @@ def showInterpolatorImpl(sc: Expr[StringContext], argsExpr: Expr[Seq[Any]])(usin
     case '[ Int ] => // error
   ???
 
-inline def (inline sc: StringContext) show (args: Any*): String = ${ showInterpolatorImpl('sc, 'args) }
+extension (inline sc: StringContext) inline def show (args: Any*): String = ${ showInterpolatorImpl('sc, 'args) }

tests/neg-macros/reflect-inline/assert_1.scala

@@ -1,7 +1,7 @@
 import scala.quoted._
 
 object api {
-  inline def (inline x: String).stripMargin2: String =
+  extension (inline x: String) inline def stripMargin2: String =
     ${ stripImpl('x) }
 
   private def stripImpl(x: Expr[String])(using qctx: QuoteContext): Expr[String] =

tests/neg-macros/tasty-string-interpolator-position-a/Macro_1.scala

@@ -3,7 +3,7 @@ import scala.language.implicitConversions
 
 object Macro {
 
-  implicit inline def (strCtx: => StringContext).f2(args: =>Any*): String = ${FIntepolator.apply('strCtx, 'args)}
+  extension (strCtx: => StringContext) implicit inline def f2(args: =>Any*): String = ${FIntepolator.apply('strCtx, 'args)}
 
 }
 

tests/neg-macros/tasty-string-interpolator-position-b/Macro_1.scala

@@ -3,7 +3,7 @@ import scala.language.implicitConversions
 
 object Macro {
 
-  implicit inline def (strCtx: => StringContext).f3(args: =>Any*): String = ${FIntepolator.apply('strCtx, 'args)}
+  extension (strCtx: => StringContext) implicit inline def f3(args: =>Any*): String = ${FIntepolator.apply('strCtx, 'args)}
 
 }
 

tests/neg/capture1.scala

@@ -4,11 +4,11 @@ object Test extends App {
 
   val l: mutable.Seq[String] = mutable.ArrayBuffer()
 
-  def [T, U](xs: List[T]) emap (f: T => U): List[U] = xs.map(f)
+  extension [T, U](xs: List[T]) def emap (f: T => U): List[U] = xs.map(f)
 
-  def [T](xs: List[T]) ereduce (f: (T, T) => T): T = xs.reduceLeft(f)
+  extension [T](xs: List[T]) def ereduce (f: (T, T) => T): T = xs.reduceLeft(f)
 
-  def [T](xs: mutable.Seq[T]) append (ys: mutable.Seq[T]): mutable.Seq[T] = xs ++ ys
+  extension [T](xs: mutable.Seq[T]) def append (ys: mutable.Seq[T]): mutable.Seq[T] = xs ++ ys
 
   List(l, mutable.ArrayBuffer(1))
     .emap(list => list)

tests/neg/extension-method-not-allowed.check

@@ -1,4 +1,4 @@
--- Error: tests/neg/extension-method-not-allowed.scala:3:8 -------------------------------------------------------------
-3 |    def (c: T).f: T = ??? // error : No extension method allowed here
-  |    ^^^^^^^^^^^^^^^^^^^^^
-  |    no extension method allowed here since leading parameter was already given
+-- Error: tests/neg/extension-method-not-allowed.scala:3:15 ------------------------------------------------------------
+3 |    extension (c: T) def f: T = ??? // error : No extension method allowed here
+  |               ^^^^^^^^^^^^^^^^^^^^
+  |               extension clause can only define methods

tests/neg/extension-method-not-allowed.scala

@@ -1,5 +1,5 @@
 object Test {
   extension on[T] (t: T) {
-    def (c: T).f: T = ??? // error : No extension method allowed here
+    extension (c: T) def f: T = ??? // error : No extension method allowed here
   }
 }

tests/neg/extension-methods.scala

@@ -1,7 +1,7 @@
 object Test {
 
   implicit object O {
-    def (x: String).l1 = x.length
+    extension (x: String) def l1 = x.length
     def l1(x: Int) = x * x
     def l2(x: String) = x.length
   }
@@ -11,7 +11,7 @@ object Test {
   1.l1 // error
 
   extension on [T](xs: List[T]) {
-    def (x: Int).f1: T = ???  // error: No extension method allowed here, since collective parameters are given
+    extension (x: Int) def f1: T = ???  // error: No extension method allowed here, since collective parameters are given
     def f2[T]: T = ???        // error: T is already defined as type T
     def f3(xs: List[T]) = ??? // error: xs is already defined as value xs
   }

tests/neg/extmethod-override.scala

@@ -1,8 +1,8 @@
 class A {
   def f(x: Int)(y: Int): Int = 0
-  def (x: Int).g(y: Int): Int = 1
+  extension (x: Int) def g(y: Int): Int = 1
 }
 class B extends A {
-  override def (x: Int).f(y: Int): Int = 1  // error
+  extension (x: Int) override def f(y: Int): Int = 1  // error
   override def g(x: Int)(y: Int): Int = 0    // error
 }

tests/neg/i5773.scala

@@ -1,16 +1,16 @@
 trait Semigroup[T] {
-  def (lhs: T).append(rhs: T): T
-  def (lhs: Int).appendS(rhs: T): T = ???
+  extension (lhs: T) def append(rhs: T): T
+  extension (lhs: Int) def appendS(rhs: T): T = ???
 }
 
 object Semigroup {
   implicit object stringAppend extends Semigroup[String] {
-    override def (lhs: String).append(rhs: String): String = lhs + rhs
+    extension (lhs: String) override def append(rhs: String): String = lhs + rhs
   }
 
   implicit def sumSemigroup[N](implicit N: Numeric[N]): Semigroup[N] = new {
-    override def (lhs: N).append(rhs: N): N = N.plus(lhs, rhs)
-    def (lhs: Int).appendS(rhs: N): N = ??? // N.plus(lhs, rhs)
+    extension (lhs: N) override def append(rhs: N): N = N.plus(lhs, rhs)
+    extension (lhs: Int) def appendS(rhs: N): N = ??? // N.plus(lhs, rhs)
   }
 }
 

tests/neg/i6662.scala

@@ -1,9 +1,9 @@
 opaque type Opt[A >: Null] = A
 
-inline def [A >: Null](x: Opt[A]) nonEmpty: Boolean = x.get != null // error: Implementation restriction
-inline def [A >: Null](x: Opt[A]) isEmpty: Boolean = x.get == null // error: Implementation restriction
-inline def [A >: Null](x: Opt[A]) isDefined: Boolean = x.nonEmpty // error: Implementation restriction
-inline def [A >: Null](x: Opt[A]) get: A = Opt.unOpt(x) // error: Implementation restriction
+extension [A >: Null](x: Opt[A]) inline def nonEmpty: Boolean = x.get != null // error: Implementation restriction
+extension [A >: Null](x: Opt[A]) inline def isEmpty: Boolean = x.get == null // error: Implementation restriction
+extension [A >: Null](x: Opt[A]) inline def isDefined: Boolean = x.nonEmpty // error: Implementation restriction
+extension [A >: Null](x: Opt[A]) inline def get: A = Opt.unOpt(x) // error: Implementation restriction
 
 object Opt
 {

tests/neg/i6762b.scala

@@ -9,5 +9,5 @@ type Liftable
 given Liftable = ???
 
 implicit object ExprOps {
-  def [T](x: T).toExpr(using Liftable): Expr[T] = ???
+  extension [T](x: T) def toExpr(using Liftable): Expr[T] = ???
 }