Updated syntax documentation

Author: milessabin

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

@@ -850,9 +850,13 @@ object Parsers {
      */
     def toplevelTyp(): Tree = rejectWildcardType(typ())
 
-    /** Type        ::=  FunTypeMods FunArgTypes `=>' Type
-     *                |  HkTypeParamClause `=>>' Type
+    /** Type        ::=  FunType
+     *                |  HkTypeParamClause ‘=>>’ Type
+     *                |  MatchType
      *                |  InfixType
+     *  FunType     ::=  { 'erased' | 'given' } (MonoFunType | PolyFunType)
+     *  MonoFunType ::=  FunArgTypes ‘=>’ Type
+     *  PolyFunType ::=  HKTypeParamClause '=>' Type
      *  FunArgTypes ::=  InfixType
      *                |  `(' [ FunArgType {`,' FunArgType } ] `)'
      *                |  '(' TypedFunParam {',' TypedFunParam } ')'
@@ -1234,6 +1238,7 @@ object Parsers {
      *                      |  `throw' Expr
      *                      |  `return' [Expr]
      *                      |  ForExpr
+     *                      |  HkTypeParamClause ‘=>’ Expr
      *                      |  [SimpleExpr `.'] id `=' Expr
      *                      |  SimpleExpr1 ArgumentExprs `=' Expr
      *                      |  Expr2

docs/docs/internals/syntax.md

@@ -139,10 +139,13 @@ ClassQualifier    ::=  ‘[’ id ‘]’
 
 ### Types
 ```ebnf
-Type              ::=  { ‘erased’ | ‘given’} FunArgTypes ‘=>’ Type              Function(ts, t)
-                    |  HkTypeParamClause ‘=>>’ Type                              TypeLambda(ps, t)
+Type              ::=  FunType
+                    |  HkTypeParamClause ‘=>>’ Type                             TypeLambda(ps, t)
                     |  MatchType
                     |  InfixType
+FunType           ::=  { 'erased' | 'given' } (MonoFunType | PolyFunType)
+MonoFunType       ::=  FunArgTypes ‘=>’ Type                                    Function(ts, t)
+PolyFunType       :: = HKTypeParamClause '=>' Type                              PolyFunction(ps, t)
 FunArgTypes       ::=  InfixType
                     |  ‘(’ [ FunArgType {‘,’ FunArgType } ] ‘)’
                     |  ‘(’ TypedFunParam {‘,’ TypedFunParam } ‘)’
@@ -195,6 +198,7 @@ Expr1             ::=  ‘if’ ‘(’ Expr ‘)’ {nl}
                     |  ‘throw’ Expr                                             Throw(expr)
                     |  ‘return’ [Expr]                                          Return(expr?)
                     |  ForExpr
+                    |  HkTypeParamClause ‘=>’ Expr                              PolyFunction(ts, expr)
                     |  [SimpleExpr ‘.’] id ‘=’ Expr                             Assign(expr, expr)
                     |  SimpleExpr1 ArgumentExprs ‘=’ Expr                       Assign(expr, expr)
                     |  Expr2