Support all atomic types as nullable types

Author: rvanvelzen

Diff for: doc/grammars/type.abnf

@@ -20,7 +20,7 @@ Conditional
     = 1*ByteHorizontalWs TokenIs [TokenNot] Atomic TokenNullable Atomic TokenColon Atomic
 
 Nullable
-	= TokenNullable TokenIdentifier [Generic]
+	= TokenNullable Atomic
 
 Atomic
 	= TokenIdentifier [Generic / Callable / Array]

Diff for: src/Parser/TypeParser.php

@@ -282,19 +282,7 @@ private function parseNullable(TokenIterator $tokens): Ast\Type\TypeNode
 	{
 		$tokens->consumeTokenType(Lexer::TOKEN_NULLABLE);
 
-		$type = new Ast\Type\IdentifierTypeNode($tokens->currentTokenValue());
-		$tokens->consumeTokenType(Lexer::TOKEN_IDENTIFIER);
-
-		if ($tokens->isCurrentTokenType(Lexer::TOKEN_OPEN_ANGLE_BRACKET)) {
-			$type = $this->parseGeneric($tokens, $type);
-
-		} elseif ($type->name === 'array' && $tokens->isCurrentTokenType(Lexer::TOKEN_OPEN_CURLY_BRACKET) && !$tokens->isPrecededByHorizontalWhitespace()) {
-			$type = $this->parseArrayShape($tokens, $type);
-		}
-
-		if ($tokens->isCurrentTokenType(Lexer::TOKEN_OPEN_SQUARE_BRACKET)) {
-			$type = $this->tryParseArrayOrOffsetAccess($tokens, $type);
-		}
+		$type = $this->parseAtomic($tokens);
 
 		return new Ast\Type\NullableTypeNode($type);
 	}

Diff for: tests/PHPStan/Parser/TypeParserTest.php

@@ -1255,6 +1255,17 @@ public function provideParseData(): array
 					false
 				),
 			],
+			[
+				'?Currency::CURRENCY_*',
+				new NullableTypeNode(
+					new ConstTypeNode(
+						new ConstFetchNode(
+							'Currency',
+							'CURRENCY_*'
+						)
+					)
+				),
+			],
 		];
 	}