Merge pull request #7568 from dotty-staging/add-end-given

Allow `end given` as an end marker

Author: odersky

compiler/src/dotty/tools/dotc/parsing/Parsers.scala

@@ -3412,7 +3412,7 @@ object Parsers {
         else
           (EmptyTermName, isIdent(nme.extension))
 
-      val gdef = indentRegion(name) {
+      val gdef = indentRegion(if name.isEmpty then GIVEN else name) {
         if isExtension then
           if (in.token == COLON) in.nextToken()
           assert(ident() == nme.extension)

compiler/src/dotty/tools/dotc/parsing/Scanners.scala

@@ -345,7 +345,7 @@ object Scanners {
 
         lookahead.token match {
           case IDENTIFIER | BACKQUOTED_IDENT => handle(lookahead.name)
-          case IF | WHILE | FOR | MATCH | TRY | NEW => handle(lookahead.token)
+          case IF | WHILE | FOR | MATCH | TRY | NEW | GIVEN => handle(lookahead.token)
           case _ =>
         }
       }

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

@@ -109,7 +109,7 @@ end largeMethod
 ```
 An `end` marker consists of the identifier `end` which follows an `<outdent>` token, and is in turn followed on the same line by exactly one other token, which is either an identifier or one of the reserved words
 ```scala
-if  while  for  match  try  new
+if  while  for  match  try  new  given
 ```
 If `end` is followed by a reserved word, the compiler checks that the marker closes an indentation region belonging to a construct that starts with the reserved word. If it is followed by an identifier _id_, the compiler checks that the marker closes a definition
 that defines _id_ or a package clause that refers to _id_.

tests/pos/end-given.scala

@@ -0,0 +1,3 @@
+given Conversion[Int, String] with
+  def apply(x: Int) = ""
+end given