Merge pull request #11215 from unkarjedy/patch-3

syntax.md: support multiple if-guards on same line

Author: odersky

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

@@ -2478,7 +2478,7 @@ object Parsers {
       else Nil
 
     /** Enumerator  ::=  Generator
-     *                |  Guard
+     *                |  Guard {Guard}
      *                |  Pattern1 `=' Expr
      */
     def enumerator(): Tree =

docs/docs/internals/syntax.md

@@ -280,9 +280,9 @@ ForExpr           ::=  ‘for’ ‘(’ Enumerators0 ‘)’ {nl} [‘do‘ | 
 Enumerators0      ::=  {nl} Enumerators [semi]
 Enumerators       ::=  Generator {semi Enumerator | Guard}
 Enumerator        ::=  Generator
-                    |  Guard
+                    |  Guard {Guard}
                     |  Pattern1 ‘=’ Expr                                        GenAlias(pat, expr)
-Generator         ::=  [‘case’] Pattern1 ‘<-’ Expr                                       GenFrom(pat, expr)
+Generator         ::=  [‘case’] Pattern1 ‘<-’ Expr                              GenFrom(pat, expr)
 Guard             ::=  ‘if’ PostfixExpr
 
 CaseClauses       ::=  CaseClause { CaseClause }                                Match(EmptyTree, cases)

docs/docs/reference/syntax.md

@@ -273,7 +273,7 @@ ForExpr           ::=  ‘for’ ‘(’ Enumerators0 ‘)’ {nl} [‘do‘ | 
 Enumerators0      ::=  {nl} Enumerators [semi]
 Enumerators       ::=  Generator {semi Enumerator | Guard}
 Enumerator        ::=  Generator
-                    |  Guard
+                    |  Guard {Guard}
                     |  Pattern1 ‘=’ Expr
 Generator         ::=  [‘case’] Pattern1 ‘<-’ Expr
 Guard             ::=  ‘if’ PostfixExpr