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PHP 8.0 | Tokenizer/PHP: add support for match expressions in combination with arrow functions
As a match expression can be nested in an arrow function and visa versa, setting the scope openers/closers becomes _interesting_. If the arrow function would be allowed to take over, it would break the scope setting for match expression, making the `scope_closer` and `scope_condition` indexes next to useless. So in the interest of making things easier for sniff writers and keeping in mind that scope setting for arrow functions isn't perfect anyway, preference is given to keeping the scope setting for match structures intact. This means that if a match expression is in the return value of an arrow function, like so: ```php $fn = fn($x) => match($y) {...}; ``` ... the token _after_ the closing curly belonging to the `match` will be considered the scope closer for the arrow function. In this example, that is the `;` (semicolon). While, if an arrow function is the return value of one of the match expression cases, generally speaking the comma at the end of the case will be the scope closer for the arrow function. There is one exception to this: the comma after each case is optional for the last case in a match expression. In that situation, the last non-empty token will be considered the scope closer for the arrow function. Example: ```php $match = match($y) { default => fn($x) => $y * $x }; ``` In this example, the `$x` at the end of the arrow expression would be considered the scope closer for the arrow function. ```php $match = match($y) { default => fn($x) => ($y * $x) }; ``` And in this example, the parenthesis closer at the end of the arrow expression would be considered the scope closer for the arrow function.
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‎src/Tokenizers/PHP.php

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Original file line numberDiff line numberDiff line change
@@ -2242,6 +2242,31 @@ protected function processAdditional()
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$lastEndToken = null;
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for ($scopeCloser = ($arrow + 1); $scopeCloser < $numTokens; $scopeCloser++) {
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// Arrow function closer should never be shared with the closer of a match
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// control structure.
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if (isset($this->tokens[$scopeCloser]['scope_closer'], $this->tokens[$scopeCloser]['scope_condition']) === true
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&& $scopeCloser === $this->tokens[$scopeCloser]['scope_closer']
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&& $this->tokens[$this->tokens[$scopeCloser]['scope_condition']]['code'] === T_MATCH
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) {
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if ($arrow < $this->tokens[$scopeCloser]['scope_condition']) {
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// Match in return value of arrow function. Move on to the next token.
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continue;
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}
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// Arrow function as return value for the last match case without trailing comma.
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if ($lastEndToken !== null) {
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$scopeCloser = $lastEndToken;
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break;
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}
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for ($lastNonEmpty = ($scopeCloser - 1); $lastNonEmpty > $arrow; $lastNonEmpty--) {
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if (isset(Util\Tokens::$emptyTokens[$this->tokens[$lastNonEmpty]['code']]) === false) {
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$scopeCloser = $lastNonEmpty;
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break 2;
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}
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}
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}
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if (isset($endTokens[$this->tokens[$scopeCloser]['code']]) === true) {
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if ($lastEndToken !== null
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&& $this->tokens[$scopeCloser]['code'] === T_CLOSE_PARENTHESIS

‎tests/Core/Tokenizer/BackfillFnTokenTest.inc

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Original file line numberDiff line numberDiff line change
@@ -90,6 +90,46 @@ $arrowWithUnionReturn = fn($param) : int|float => $param | 10;
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/* testTernary */
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$fn = fn($a) => $a ? /* testTernaryThen */ fn() : string => 'a' : /* testTernaryElse */ fn() : string => 'b';
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function matchInArrow($x) {
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/* testWithMatchValue */
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$fn = fn($x) => match(true) {
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1, 2, 3, 4, 5 => 'foo',
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default => 'bar',
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};
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}
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function matchInArrowAndMore($x) {
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/* testWithMatchValueAndMore */
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$fn = fn($x) => match(true) {
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1, 2, 3, 4, 5 => 'foo',
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default => 'bar',
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} . 'suffix';
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}
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function arrowFunctionInMatchWithTrailingComma($x) {
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return match ($x) {
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/* testInMatchNotLastValue */
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1 => fn($y) => callMe($y),
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/* testInMatchLastValueWithTrailingComma */
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default => fn($y) => callThem($y),
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};
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}
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function arrowFunctionInMatchNoTrailingComma1($x) {
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return match ($x) {
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1 => fn($y) => callMe($y),
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/* testInMatchLastValueNoTrailingComma1 */
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default => fn($y) => callThem($y)
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};
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}
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function arrowFunctionInMatchNoTrailingComma2($x) {
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return match ($x) {
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/* testInMatchLastValueNoTrailingComma2 */
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default => fn($y) => 5 * $y
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};
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}
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/* testConstantDeclaration */
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const FN = 'a';
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‎tests/Core/Tokenizer/BackfillFnTokenTest.php

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Original file line numberDiff line numberDiff line change
@@ -465,6 +465,109 @@ public function testTernary()
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}//end testTernary()
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/**
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* Test arrow function returning a match control structure.
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*
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* @covers PHP_CodeSniffer\Tokenizers\PHP::processAdditional
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*
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* @return void
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*/
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public function testWithMatchValue()
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{
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$token = $this->getTargetToken('/* testWithMatchValue */', T_FN);
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$this->backfillHelper($token);
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$this->scopePositionTestHelper($token, 5, 44);
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}//end testWithMatchValue()
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/**
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* Test arrow function returning a match control structure with something behind it.
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*
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* @covers PHP_CodeSniffer\Tokenizers\PHP::processAdditional
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*
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* @return void
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*/
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public function testWithMatchValueAndMore()
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{
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$token = $this->getTargetToken('/* testWithMatchValueAndMore */', T_FN);
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$this->backfillHelper($token);
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$this->scopePositionTestHelper($token, 5, 48);
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}//end testWithMatchValueAndMore()
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/**
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* Test match control structure returning arrow functions.
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*
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* @param string $testMarker The comment prefacing the target token.
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* @param int $openerOffset The expected offset of the scope opener in relation to the testMarker.
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* @param int $closerOffset The expected offset of the scope closer in relation to the testMarker.
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* @param string $expectedCloserType The type of token expected for the scope closer.
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* @param string $expectedCloserFriendlyName A friendly name for the type of token expected for the scope closer
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* to be used in the error message for failing tests.
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*
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* @dataProvider dataInMatchValue
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* @covers PHP_CodeSniffer\Tokenizers\PHP::processAdditional
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*
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* @return void
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*/
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public function testInMatchValue($testMarker, $openerOffset, $closerOffset, $expectedCloserType, $expectedCloserFriendlyName)
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{
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$tokens = self::$phpcsFile->getTokens();
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$token = $this->getTargetToken($testMarker, T_FN);
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$this->backfillHelper($token);
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$this->scopePositionTestHelper($token, $openerOffset, $closerOffset, $expectedCloserFriendlyName);
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$this->assertSame($expectedCloserType, $tokens[($token + $closerOffset)]['type'], 'Mismatched scope closer type');
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}//end testInMatchValue()
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/**
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* Data provider.
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*
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* @see testInMatchValue()
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*
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* @return array
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*/
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public function dataInMatchValue()
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{
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return [
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'not_last_value' => [
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'/* testInMatchNotLastValue */',
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5,
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11,
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'T_COMMA',
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'comma',
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],
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'last_value_with_trailing_comma' => [
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'/* testInMatchLastValueWithTrailingComma */',
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5,
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11,
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'T_COMMA',
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'comma',
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],
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'last_value_without_trailing_comma_1' => [
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'/* testInMatchLastValueNoTrailingComma1 */',
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5,
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10,
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'T_CLOSE_PARENTHESIS',
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'close parenthesis',
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],
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'last_value_without_trailing_comma_2' => [
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'/* testInMatchLastValueNoTrailingComma2 */',
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5,
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11,
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'T_VARIABLE',
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'$y variable',
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],
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];
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}//end dataInMatchValue()
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/**
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* Test arrow function nested within a method declaration.
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*

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