Switch default source version to 3.6 (#20895)

Author: WojciechMazur

Diff for: compiler/src/dotty/tools/dotc/config/SourceVersion.scala

@@ -12,6 +12,7 @@ enum SourceVersion:
   case `3.4-migration`, `3.4`
   case `3.5-migration`, `3.5`
   case `3.6-migration`, `3.6`
+  case `3.7-migration`, `3.7`
   // !!! Keep in sync with scala.runtime.stdlibPatches.language !!!
   case `future-migration`, `future`
 
@@ -28,7 +29,7 @@ enum SourceVersion:
   def isAtMost(v: SourceVersion) = stable.ordinal <= v.ordinal
 
 object SourceVersion extends Property.Key[SourceVersion]:
-  def defaultSourceVersion = `3.5`
+  def defaultSourceVersion = `3.6`
 
   /** language versions that may appear in a language import, are deprecated, but not removed from the standard library. */
   val illegalSourceVersionNames = List("3.1-migration").map(_.toTermName)

Diff for: library/src/scala/runtime/stdLibPatches/language.scala

@@ -300,6 +300,21 @@ object language:
   @compileTimeOnly("`3.6` can only be used at compile time in import statements")
   object `3.6`
 
+  /** Set source version to 3.7-migration.
+    *
+    * @see [[https://docs.scala-lang.org/scala3/guides/migration/compatibility-intro.html]]
+    */
+  @compileTimeOnly("`3.7-migration` can only be used at compile time in import statements")
+  object `3.7-migration`
+
+  /** Set source version to 3.7
+    *
+    * @see [[https://docs.scala-lang.org/scala3/guides/migration/compatibility-intro.html]]
+    */
+  @compileTimeOnly("`3.7` can only be used at compile time in import statements")
+  object `3.7`
+
+
   // !!! Keep in sync with dotty.tools.dotc.config.SourceVersion !!!
   // Also add tests in `tests/pos/source-import-3-x.scala` and `tests/pos/source-import-3-x-migration.scala`
 

Diff for: tests/neg/given-loop-prevention.check

@@ -1,14 +1,4 @@
--- Error: tests/neg/given-loop-prevention.scala:10:36 ------------------------------------------------------------------
+-- [E172] Type Error: tests/neg/given-loop-prevention.scala:10:36 ------------------------------------------------------
 10 |  given List[Foo] = List(summon[Foo]) // error
    |                                    ^
-   |                             Result of implicit search for Foo will change.
-   |                             Current result Baz.given_Foo will be no longer eligible
-   |                               because it is not defined before the search position.
-   |                             Result with new rules: No Matching Implicit.
-   |                             To opt into the new rules, compile with `-source future` or use
-   |                             the `scala.language.future` language import.
-   |
-   |                             To fix the problem without the language import, you could try one of the following:
-   |                               - use a `given ... with` clause as the enclosing given,
-   |                               - rearrange definitions so that Baz.given_Foo comes earlier,
-   |                               - use an explicit argument.
+   |                       No given instance of type Foo was found for parameter x of method summon in object Predef

Diff for: tests/neg/i20415.scala

@@ -1,17 +1,12 @@
-
-trait Monad[T]:
-  def id: String
 class Foo
-object Foo {
-  given Monad[Foo] with { def id = "Foo" }
-}
 
-opaque type Bar = Foo
 object Bar {
-  given Monad[Bar] = summon[Monad[Foo]] // error
+  given Foo with {}
+  given List[Foo] = List(summon[Foo]) // ok
 }
 
-object Test extends App {
-  println(summon[Monad[Foo]].id)
-  println(summon[Monad[Bar]].id)
+object Baz {
+  @annotation.nowarn
+  given List[Foo] = List(summon[Foo]) // error
+  given Foo with {}
 }

Diff for: tests/neg/i6716.check

@@ -1,25 +1,9 @@
--- Error: tests/neg/i7294.scala:7:10 -----------------------------------------------------------------------------------
-7 |  case x: T => x.g(10) // error // error
-  |          ^
-  |          Result of implicit search for scala.reflect.TypeTest[Nothing, T] will change.
-  |          Current result foo.f will be no longer eligible
-  |            because it is not defined before the search position.
-  |          Result with new rules: No Matching Implicit.
-  |          To opt into the new rules, compile with `-source future` or use
-  |          the `scala.language.future` language import.
-  |
-  |          To fix the problem without the language import, you could try one of the following:
-  |            - use a `given ... with` clause as the enclosing given,
-  |            - rearrange definitions so that foo.f comes earlier,
-  |            - use an explicit argument.
-  |
-  |          where:    T is a type in given instance f with bounds <: foo.Foo
--- [E007] Type Mismatch Error: tests/neg/i7294.scala:7:18 --------------------------------------------------------------
-7 |  case x: T => x.g(10) // error // error
-  |               ^^^^^^^
-  |               Found:    Any
-  |               Required: T
-  |
-  |               where:    T is a type in given instance f with bounds <: foo.Foo
+-- [E007] Type Mismatch Error: tests/neg/i7294.scala:7:15 --------------------------------------------------------------
+7 |  case x: T => x.g(10) // error
+  |               ^
+  |               Found:    (x : Nothing)
+  |               Required: ?{ g: ? }
+  |               Note that implicit conversions were not tried because the result of an implicit conversion
+  |               must be more specific than ?{ g: [applied to (10) returning T] }
   |
   | longer explanation available when compiling with `-explain`

Diff for: tests/neg/i6716.scala

@@ -4,7 +4,7 @@ package foo
 trait Foo { def g(x: Any): Any }
 
 inline given f[T <: Foo]: T = ??? match {
-  case x: T => x.g(10) // error // error
+  case x: T => x.g(10) // error
 }
 
 @main def Test = f

Diff for: tests/neg/i7294.check

@@ -0,0 +1,2 @@
+class Foo:
+  given ord: Ordering[Int] = summon[Ordering[Int]]

Diff for: tests/neg/i7294.scala

@@ -1,14 +1,16 @@
-//> using options -Xfatal-warnings -source 3.4
-
+trait Monad[T]:
+  def id: String
 class Foo
+object Foo {
+  given Monad[Foo] with { def id = "Foo" }
+}
 
+opaque type Bar = Foo
 object Bar {
-  given Foo with {}
-  given List[Foo] = List(summon[Foo]) // ok
+  given Monad[Bar] = summon[Monad[Foo]]
 }
 
-object Baz {
-  @annotation.nowarn
-  given List[Foo] = List(summon[Foo]) // gives a warning, which is suppressed
-  given Foo with {}
+object Test extends App {
+  println(summon[Monad[Foo]].id)
+  println(summon[Monad[Bar]].id)
 }

Diff for: tests/neg/looping-givens.check

@@ -1,11 +1,10 @@
-import language.future
 
 class A
 class B
 
 given joint(using a: A, b: B): (A & B) = ???
 
 def foo(using a: A, b: B) =
-  given aa: A = summon       // error
-  given bb: B = summon       // error
-  given ab: (A & B) = summon // error
+  given aa: A = summon       // resolves to a
+  given bb: B = summon       // resolves to b
+  given ab: (A & B) = summon // resolves to joint(aa, bb)

Diff for: tests/neg/looping-givens.scala

@@ -0,0 +1 @@
+import language.`3.5-migration`

Diff for: tests/pos/i20415.scala

@@ -0,0 +1 @@
+import language.`3.5`

Diff for: tests/pos/i6716.scala

@@ -0,0 +1 @@
+import language.`3.6-migration`

Diff for: tests/pos/looping-givens.scala

@@ -0,0 +1 @@
+import language.`3.6`

Diff for: tests/pos/source-import-3-5-migration.scala

@@ -0,0 +1 @@
+import language.`3.7-migration`

Diff for: tests/pos/source-import-3-5.scala

@@ -0,0 +1 @@
+import language.`3.7`

Diff for: tests/pos/source-import-3-6-migration.scala

@@ -1,4 +1,4 @@
-//> using options -Xfatal-warnings -source future
+//> using options -Xfatal-warnings
 
 trait Monad[T]:
   def id: String