parse type projections

doc/grammars/type.abnf

@@ -28,7 +28,11 @@ Atomic
 	/ TokenParenthesesOpen ParenthesizedType TokenParenthesesClose [Array]
 
 Generic
-	= TokenAngleBracketOpen Type *(TokenComma Type) TokenAngleBracketClose
+	= TokenAngleBracketOpen GenericTypeArgument *(TokenComma GenericTypeArgument) TokenAngleBracketClose
+
+GenericTypeArgument
+    = [TokenContravariant / TokenCovariant] Type
+    / TokenWildcard
 
 Callable
 	= TokenParenthesesOpen [CallableParameters] TokenParenthesesClose TokenColon CallableReturnType
@@ -188,6 +192,15 @@ TokenIs
 TokenNot
     = %x6E.6F.74 1*ByteHorizontalWs
 
+TokenContravariant
+    = %x63.6F.6E.74.72.61.76.61.72.69.61.6E.74 1*ByteHorizontalWs
+
+TokenCovariant
+    = %x63.6F.76.61.72.69.61.6E.74 1*ByteHorizontalWs
+
+TokenWildcard
+	= "*" *ByteHorizontalWs
+
 TokenIdentifier
 	= [ByteBackslash] ByteIdentifierFirst *ByteIdentifierSecond *(ByteBackslash ByteIdentifierFirst *ByteIdentifierSecond) *ByteHorizontalWs
 

src/Ast/Type/StarProjectionNode.php

@@ -0,0 +1,17 @@
+<?php declare(strict_types = 1);
+
+namespace PHPStan\PhpDocParser\Ast\Type;
+
+use PHPStan\PhpDocParser\Ast\NodeAttributes;
+
+final class StarProjectionNode implements TypeNode
+{
+
+	use NodeAttributes;
+
+	public function __toString(): string
+	{
+		return '*';
+	}
+
+}

src/Ast/Type/TypeProjectionNode.php

@@ -0,0 +1,33 @@
+<?php declare(strict_types = 1);
+
+namespace PHPStan\PhpDocParser\Ast\Type;
+
+use PHPStan\PhpDocParser\Ast\NodeAttributes;
+
+class TypeProjectionNode implements TypeNode
+{
+
+	use NodeAttributes;
+
+	/** @var TypeNode */
+	public $type;
+
+	/** @var 'covariant'|'contravariant' */
+	public $variance;
+
+	/**
+	 * @param 'covariant'|'contravariant' $variance
+	 */
+	public function __construct(TypeNode $type, string $variance)
+	{
+		$this->type = $type;
+		$this->variance = $variance;
+	}
+
+
+	public function __toString(): string
+	{
+		return $this->variance . ' ' . $this->type;
+	}
+
+}

src/Parser/TypeParser.php

@@ -323,7 +323,7 @@ public function parseGeneric(TokenIterator $tokens, Ast\Type\IdentifierTypeNode
 	{
 		$tokens->consumeTokenType(Lexer::TOKEN_OPEN_ANGLE_BRACKET);
 		$tokens->tryConsumeTokenType(Lexer::TOKEN_PHPDOC_EOL);
-		$genericTypes = [$this->parse($tokens)];
+		$genericTypes = [$this->parseGenericTypeArgument($tokens)];
 
 		$tokens->tryConsumeTokenType(Lexer::TOKEN_PHPDOC_EOL);
 
@@ -333,7 +333,7 @@ public function parseGeneric(TokenIterator $tokens, Ast\Type\IdentifierTypeNode
 				// trailing comma case
 				return new Ast\Type\GenericTypeNode($baseType, $genericTypes);
 			}
-			$genericTypes[] = $this->parse($tokens);
+			$genericTypes[] = $this->parseGenericTypeArgument($tokens);
 			$tokens->tryConsumeTokenType(Lexer::TOKEN_PHPDOC_EOL);
 		}
 
@@ -344,6 +344,27 @@ public function parseGeneric(TokenIterator $tokens, Ast\Type\IdentifierTypeNode
 	}
 
 
+	/** @phpstan-impure */
+	public function parseGenericTypeArgument(TokenIterator $tokens): Ast\Type\TypeNode
+	{
+		if ($tokens->tryConsumeTokenType(Lexer::TOKEN_WILDCARD)) {
+			return new Ast\Type\StarProjectionNode();
+		}
+
+		if ($tokens->tryConsumeTokenValue('contravariant')) {
+			$variance = 'contravariant';
+		} elseif ($tokens->tryConsumeTokenValue('covariant')) {
+			$variance = 'covariant';
+		} else {
+			return $this->parse($tokens);
+		}
+
+		$type = $this->parse($tokens);
+
+		return new Ast\Type\TypeProjectionNode($type, $variance);
+	}
+
+
 	/** @phpstan-impure */
 	private function parseCallable(TokenIterator $tokens, Ast\Type\IdentifierTypeNode $identifier): Ast\Type\TypeNode
 	{

tests/PHPStan/Parser/TypeParserTest.php

@@ -20,8 +20,10 @@
 use PHPStan\PhpDocParser\Ast\Type\IntersectionTypeNode;
 use PHPStan\PhpDocParser\Ast\Type\NullableTypeNode;
 use PHPStan\PhpDocParser\Ast\Type\OffsetAccessTypeNode;
+use PHPStan\PhpDocParser\Ast\Type\StarProjectionNode;
 use PHPStan\PhpDocParser\Ast\Type\ThisTypeNode;
 use PHPStan\PhpDocParser\Ast\Type\TypeNode;
+use PHPStan\PhpDocParser\Ast\Type\TypeProjectionNode;
 use PHPStan\PhpDocParser\Ast\Type\UnionTypeNode;
 use PHPStan\PhpDocParser\Lexer\Lexer;
 use PHPUnit\Framework\TestCase;
@@ -1266,6 +1268,51 @@ public function provideParseData(): array
 					)
 				),
 			],
+			[
+				'Foo<covariant Bar, Baz>',
+				new GenericTypeNode(
+					new IdentifierTypeNode('Foo'),
+					[
+						new TypeProjectionNode(
+							new IdentifierTypeNode('Bar'),
+							'covariant'
+						),
+						new IdentifierTypeNode('Baz'),
+					]
+				),
+			],
+			[
+				'Foo<Bar, contravariant Baz>',
+				new GenericTypeNode(
+					new IdentifierTypeNode('Foo'),
+					[
+						new IdentifierTypeNode('Bar'),
+						new TypeProjectionNode(
+							new IdentifierTypeNode('Baz'),
+							'contravariant'
+						),
+					]
+				),
+			],
+			[
+				'Foo<covariant>',
+				new ParserException(
+					'>',
+					Lexer::TOKEN_CLOSE_ANGLE_BRACKET,
+					13,
+					Lexer::TOKEN_IDENTIFIER
+				),
+			],
+			[
+				'Foo<Bar, *>',
+				new GenericTypeNode(
+					new IdentifierTypeNode('Foo'),
+					[
+						new IdentifierTypeNode('Bar'),
+						new StarProjectionNode(),
+					]
+				),
+			],
 		];
 	}