Refinement

Problem
-------
Compound type with refinement (structural type with a parent)
doesn't parse.

Solution
--------
This adds support for it.
It collides with context bounds `A: B: C`, so the precedence is set to
-1.

Author: eed3si9n

corpus/types.txt

@@ -194,6 +194,10 @@ def cloneAndReset(obj: Cloneable with Resetable): Cloneable = {
 
 class F extends Cloneable with Resetable with Serializable {}
 
+type G = H[A1] {
+  def foo[A2 <: Stepper[_]]: A2
+}
+
 --------------------------------------------------------------------------------
 
 (compilation_unit
@@ -213,7 +217,25 @@ class F extends Cloneable with Resetable with Serializable {}
       (type_identifier)
       (type_identifier)
       (type_identifier))
-    (template_body)))
+    (template_body))
+  (type_definition
+    (type_identifier)
+    (compound_type
+      (generic_type
+        (type_identifier)
+        (type_arguments
+          (type_identifier)))
+      (refinement
+        (function_declaration
+          (identifier)
+          (type_parameters
+            (identifier)
+            (upper_bound
+              (generic_type
+                (type_identifier)
+                (type_arguments
+                  (wildcard)))))
+          (type_identifier))))))
 
 ================================================================================
 Infix types

grammar.js

@@ -674,14 +674,14 @@ module.exports = grammar({
     * DefParam          ::=  {Annotation} [‘inline’] Param
     * Param             ::=  id ‘:’ ParamType [‘=’ Expr]
     */
-    parameter: $ => seq(
+    parameter: $ => prec.left(PREC.control, seq(
       repeat($.annotation),
       optional($.inline_modifier),
       field('name', $._identifier),
       ':',
       field('type', $._param_type),
       optional(seq('=', field('default_value', $.expression)))
-    ),
+    )),
 
     _block: $ => prec.left(seq(
       sep1($._semicolon, choice(
@@ -752,11 +752,25 @@ module.exports = grammar({
       $.wildcard,
     ),
 
-    compound_type: $ => prec(PREC.compound, seq(
-      field('base', $._annotated_type),
-      repeat1(seq('with', field('extra', $._annotated_type))),
-      // TODO: Refinement.
-    )),
+    compound_type: $ => choice(
+      prec.left(PREC.compound, seq(
+        field('base', $._annotated_type),
+        repeat1(seq('with', field('extra', $._annotated_type))),
+      )),
+      prec.left(-1, seq(
+        field('base', $._annotated_type),
+        $._refinement,
+      )),
+      prec.left(-1, seq(
+        prec.left(PREC.compound, seq(
+          field('base', $._annotated_type),
+          repeat1(seq('with', field('extra', $._annotated_type))),
+        )),
+        $._refinement,
+      )),
+    ),
+
+    _refinement: $ => alias($.template_body, $.refinement),
 
     // This does not include _simple_type since _annotated_type covers it.
     _infix_type_choice: $ => prec.left(PREC.infix, choice(