Syntax refactoring

 - Break out optional `with` from TemplateBody production
 - Disallow `new with { ...}`.

Author: odersky

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

@@ -2046,7 +2046,7 @@ object Parsers {
       }
       else simpleExpr()
 
-    /** SimpleExpr    ::= ‘new’ (ConstrApp [TemplateBody] | TemplateBody)
+    /** SimpleExpr    ::= ‘new’ (ConstrApp [[‘with’] TemplateBody] | TemplateBody)
      *                 |  BlockExpr
      *                 |  ‘$’ ‘{’ Block ‘}’
      *                 |  Quoted
@@ -2141,7 +2141,7 @@ object Parsers {
       }
     }
 
-    /** SimpleExpr    ::=  ‘new’ ConstrApp {`with` ConstrApp} [TemplateBody]
+    /** SimpleExpr    ::=  ‘new’ ConstrApp {`with` ConstrApp} [[‘with’] TemplateBody]
      *                  |  ‘new’ TemplateBody
      */
     def newExpr(): Tree =
@@ -3312,7 +3312,7 @@ object Parsers {
       }
     }
 
-    /**  EnumDef ::=  id ClassConstr InheritClauses EnumBody
+    /**  EnumDef ::=  id ClassConstr InheritClauses [‘with’] EnumBody
      */
     def enumDef(start: Offset, mods: Modifiers): TypeDef = atSpan(start, nameStart) {
       val modulName = ident()
@@ -3381,7 +3381,7 @@ object Parsers {
     }
 
     /** GivenDef       ::=  [GivenSig (‘:’ | <:)] Type ‘=’ Expr
-     *                   |  [GivenSig ‘:’] [ConstrApp {‘,’ ConstrApp }] [TemplateBody]
+     *                   |  [GivenSig ‘:’] [ConstrApp {‘,’ ConstrApp }] [[‘with’] TemplateBody]
      *                   |  [id ‘:’] ‘extension’ ExtParamClause {GivenParamClause} ExtMethods
      *  GivenSig       ::=  [id] [DefTypeParamClause] {GivenParamClause}
      *  ExtParamClause ::=  [DefTypeParamClause] DefParamClause {GivenParamClause}
@@ -3505,7 +3505,7 @@ object Parsers {
         else Nil
       t :: ts
 
-    /** Template          ::=  InheritClauses [TemplateBody]
+    /** Template          ::=  InheritClauses [[‘with’] TemplateBody]
      *  InheritClauses    ::=  [‘extends’ ConstrApps] [‘derives’ QualId {‘,’ QualId}]
      */
     def template(constr: DefDef, isEnum: Boolean = false): Template = {

docs/docs/internals/syntax.md

@@ -214,7 +214,7 @@ SimpleExpr        ::=  Path
                     |  ‘$’ ‘{’ Block ‘}’
                     |  Quoted
                     |  quoteId     // only inside splices
-                    |  ‘new’ ConstrApp {`with` ConstrApp} [TemplateBody]        New(constr | templ)
+                    |  ‘new’ ConstrApp {‘with’ ConstrApp} [[‘with’] TemplateBody] New(constr | templ)
                     |  ‘new’ TemplateBody
                     |  ‘(’ ExprsInParens ‘)’                                    Parens(exprs)
                     |  SimpleExpr ‘.’ id                                        Select(expr, id)
@@ -383,24 +383,23 @@ ClassDef          ::=  id ClassConstr [Template]
 ClassConstr       ::=  [ClsTypeParamClause] [ConstrMods] ClsParamClauses        with DefDef(_, <init>, Nil, vparamss, EmptyTree, EmptyTree) as first stat
 ConstrMods        ::=  {Annotation} [AccessModifier]
 ObjectDef         ::=  id [Template]                                            ModuleDef(mods, name, template)  // no constructor
-EnumDef           ::=  id ClassConstr InheritClauses EnumBody                   EnumDef(mods, name, tparams, template)
+EnumDef           ::=  id ClassConstr InheritClauses [‘with’] EnumBody          EnumDef(mods, name, tparams, template)
 GivenDef          ::=  [GivenSig (‘:’ | <:)] Type ‘=’ Expr
-                    |  [GivenSig ‘:’] [ConstrApp {‘,’ ConstrApp }] [TemplateBody]
+                    |  [GivenSig ‘:’] [ConstrApp {‘,’ ConstrApp }] [[‘with’] TemplateBody]
                     |  [[id ‘:’] ‘extension’ ExtParamClause {GivenParamClause}
                        ExtMethods
 GivenSig          ::=  [id] [DefTypeParamClause] {GivenParamClause}
 ExtParamClause    ::=  [DefTypeParamClause] ‘(’ DefParam ‘)’
 ExtMethods        ::=  [nl] ‘{’ ‘def’ DefDef {semi ‘def’ DefDef} ‘}’
-Template          ::=  InheritClauses [TemplateBody]                            Template(constr, parents, self, stats)
+Template          ::=  InheritClauses [[‘with’] TemplateBody]                   Template(constr, parents, self, stats)
 InheritClauses    ::=  [‘extends’ ConstrApps] [‘derives’ QualId {‘,’ QualId}]
 ConstrApps        ::=  ConstrApp {(‘,’ | ‘with’) ConstrApp}
 ConstrApp         ::=  AnnotType {ParArgumentExprs}                             Apply(tp, args)
 ConstrExpr        ::=  SelfInvocation
                     |  ‘{’ SelfInvocation {semi BlockStat} ‘}’
 SelfInvocation    ::=  ‘this’ ArgumentExprs {ArgumentExprs}
 
-TemplateBody      ::=  [nl | ‘with’]
-                       ‘{’ [SelfType] TemplateStat {semi TemplateStat} ‘}’      (self, stats)
+TemplateBody      ::=  [nl] ‘{’ [SelfType] TemplateStat {semi TemplateStat} ‘}’      (self, stats)
 TemplateStat      ::=  Import
                     |  Export
                     |  {Annotation [nl]} {Modifier} Def

tests/neg/new-with.scala

@@ -0,0 +1 @@
+val x = new with { } // error