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Max Brunsfeld
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Merge pull request tree-sitter#1 from mads-hartmann/type-parameter-variance
Type parameter variance
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‎README.md‎

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@@ -9,3 +9,20 @@ References
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* [The Scala Language Specification](http://www.scala-lang.org/docu/files/ScalaReference.pdf)
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* [Scala Syntax Summary](https://www.scala-lang.org/files/archive/spec/2.11/13-syntax-summary.html)
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Development
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-----------
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First, install the project's dependencies:
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```sh
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npm install
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```
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Add a test case to `./corpus`, make the required changes to `grammar.js`,
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regenerate and recompile the parser, and run the tests:
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```sh
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npm run build
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npm test
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```

‎corpus/definitions.txt‎

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================================
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Package
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================================
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package a.b
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package c {
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object A
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}
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---
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(compilation_unit
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(package_clause (package_identifier (identifier) (identifier)))
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(package_clause (package_identifier (identifier))
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(template_body
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(object_definition (identifier)))))
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================================
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Package object
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================================
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package object d extends A {
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val hello: String = "there"
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}
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---
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(compilation_unit
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(package_object
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(identifier)
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(extends_clause (type_identifier))
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(template_body
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(val_definition (identifier) (type_identifier) (string)))))
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================================
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Imports
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================================
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import PartialFunction.condOpt
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import a.b, c.e
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import reflect.io.{Directory, File, Path}
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import tools.nsc.classpath._
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import lang.System.{lineSeparator => EOL}
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---
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@@ -14,10 +47,33 @@ import lang.System.{lineSeparator => EOL}
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(stable_identifier (identifier) (identifier)))
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(import_declaration
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(stable_identifier (identifier) (identifier))
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(import_selectors (identifier) (identifier) (identifier)))
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(stable_identifier (identifier) (identifier)))
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(import_declaration
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(stable_identifier (identifier) (identifier))
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(import_selectors (identifier) (identifier) (identifier))))
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================================
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Imports: Wildcard
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================================
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import tools.nsc.classpath._
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---
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(compilation_unit
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(import_declaration
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(stable_identifier (stable_identifier (identifier) (identifier)) (identifier))
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(wildcard))
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(wildcard)))
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================================
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Imports: Rename
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================================
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import lang.System.{lineSeparator => EOL}
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---
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(compilation_unit
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(import_declaration
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(stable_identifier (identifier) (identifier))
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(import_selectors (renamed_identifier (identifier) (identifier)))))
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case object O2 {
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}
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object O3 extends A {
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}
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---
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(compilation_unit
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(comment)
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(object_definition (identifier) (template_body))
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(object_definition (identifier) (template_body)))
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(object_definition (identifier) (template_body))
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(object_definition (identifier) (extends_clause (type_identifier)) (template_body)))
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=======================================
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Class definitions

‎corpus/types.txt‎

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@@ -87,3 +87,83 @@ type A = B Foo C
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(type_definition
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(type_identifier)
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(infix_type (type_identifier) (identifier) (type_identifier))))
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==================================
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Variant Types
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==================================
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class Function1[-T1, +R]
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---
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(compilation_unit
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(class_definition
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(identifier)
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(type_parameters
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(contravariant_type_parameter (identifier))
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(covariant_type_parameter (identifier)))))
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==================================
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Upper bound
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==================================
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class A[B <: C]
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---
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(compilation_unit
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(class_definition
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(identifier)
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(type_parameters
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(identifier)
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(upper_bound (type_identifier)))))
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==================================
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Lower bound
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==================================
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class A[B >: C]
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---
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(compilation_unit
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(class_definition
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(identifier)
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(type_parameters
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(identifier)
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(lower_bound (type_identifier)))))
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==================================
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View bound
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==================================
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class A[B <% C <% D]
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---
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(compilation_unit
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(class_definition
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(identifier)
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(type_parameters
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(identifier)
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(view_bound (type_identifier))
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(view_bound (type_identifier)))))
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==================================
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Context bound
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==================================
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class A[B : C : D]
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---
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(compilation_unit
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(class_definition
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(identifier)
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(type_parameters
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(identifier)
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(context_bound (type_identifier))
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(context_bound (type_identifier)))))

‎examples/Packages.scala‎

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package a.b
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package c {
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object A
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}
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package c {
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package object d {
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val hello: String = "there"
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}
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}

‎examples/Variance.scala‎

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class Function1[-T1, +R]

‎grammar.js‎

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@@ -39,6 +39,7 @@ module.exports = grammar({
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_definition: $ => choice(
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$.package_clause,
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$.package_object,
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$.class_definition,
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$.import_declaration,
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$.object_definition,
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package_clause: $ => seq(
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'package',
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choice($.identifier, $.stable_identifier)
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$.package_identifier,
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// This is slightly more permissive than the EBNF in that it allows any
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// kind of delcaration inside of the package blocks. As we're more
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// concerned with the structure rather than the validity of the program
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// we'll allow it.
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optional($.template_body)
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),
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package_identifier: $ => sep1(
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'.', $.identifier
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),
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package_object: $ => seq(
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'package',
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'object',
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$._object_definition
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),
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import_declaration: $ => seq(
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'import',
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sep1(',', $._import_expression)
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),
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_import_expression: $ => seq(
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choice($.stable_identifier, $.identifier),
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optional(seq(
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'.',
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object_definition: $ => seq(
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optional('case'),
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'object',
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$._object_definition
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),
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_object_definition: $ => seq(
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$.identifier,
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$.template_body
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optional($.extends_clause),
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optional($.template_body),
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),
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class_definition: $ => seq(
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$.template_body
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),
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// The EBNF makes a distinction between function type parameters and other
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// type parameters as you can't specify variance on function type
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// parameters. This isn't important to the structure of the AST so we don't
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// make that distinction.
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type_parameters: $ => seq(
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'[',
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commaSep1($._type_parameter),
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commaSep1($._variant_type_parameter),
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']'
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),
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_type_parameter: $ => choice(
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'_',
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$.identifier
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_variant_type_parameter: $ => seq(
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choice(
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$.covariant_type_parameter,
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$.contravariant_type_parameter,
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$._type_parameter // invariant type parameter
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)
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),
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covariant_type_parameter: $ => seq(
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'+',
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$._type_parameter
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),
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contravariant_type_parameter: $ => seq(
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'-',
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$._type_parameter,
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),
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_type_parameter: $ => seq(
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choice($.wildcard, $.identifier),
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optional($.type_parameters),
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optional($.upper_bound),
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optional($.lower_bound),
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optional(repeat($.view_bound)),
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optional(repeat($.context_bound)),
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),
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upper_bound: $ => seq('<:', $._type),
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lower_bound: $ => seq('>:', $._type),
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view_bound: $ => seq('<%', $._type),
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context_bound: $ => seq(':', $._type),
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template_body: $ => seq(
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'{',
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repeat($._definition),

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