File::getMethodProperties(): bug fix - skip over closure use statements

While working on something else, I came across this beauty of a bug for which I'm flabbergasted that it hasn't been reported before, though I can only presume that this means it has been a bug with little impact.

The short of it is that the `File::getMethodProperties()` method previously did not skip over closure `use` statements when walking the tokens to find the return type.

As closure `use` statements can only contain variables, the only tokens which could be encountered in a closure `use` statement, which could also be encountered in a return type declaration are the `T_STRING`, `T_SELF`, `T_PARENT` and the `T_STATIC` tokens in the case when the variable being imported is a class property, i.e. the property name part of `$this->name` or `self` in `self::$name`.

Either way, this patch fixes the issue.

Includes unit tests.

src/Files/File.php

@@ -1757,6 +1757,20 @@ public function getMethodProperties($stackPtr)
                     break;
                 }
 
+                if ($this->tokens[$i]['code'] === T_USE) {
+                    // Skip over closure use statements.
+                    for ($j = ($i + 1); $j < $this->numTokens && isset(Tokens::$emptyTokens[$this->tokens[$j]['code']]) === true; $j++);
+                    if ($this->tokens[$j]['code'] === T_OPEN_PARENTHESIS) {
+                        if (isset($this->tokens[$j]['parenthesis_closer']) === false) {
+                            // Live coding/parse error, stop parsing.
+                            break;
+                        }
+
+                        $i = $this->tokens[$j]['parenthesis_closer'];
+                        continue;
+                    }
+                }
+
                 if ($this->tokens[$i]['code'] === T_NULLABLE) {
                     $nullableReturnType = true;
                 }

tests/Core/File/GetMethodPropertiesTest.inc

@@ -190,6 +190,24 @@ $value = $obj->fn(true);
 /* testFunctionDeclarationNestedInTernaryPHPCS2975 */
 return (!$a ? [ new class { public function b(): c {} } ] : []);
 
+/* testClosureWithUseNoReturnType */
+$closure = function () use($a) /*comment*/ {};
+
+/* testClosureWithUseNoReturnTypeUseProp */
+$closure = function () use ($this->prop){};
+
+/* testClosureWithUseWithReturnType */
+$closure = function () use /*comment*/ ($a): Type {};
+
+/* testClosureWithUseWithReturnTypeUseProp */
+$closure = function () use ($this->prop): ?array {};
+
+/* testClosureWithUseWithReturnTypeUseStaticPropWithSelf */
+$closure = function() use(self::$prop) : int {};
+
+/* testClosureWithUseWithReturnTypeUseStaticPropWithStatic */
+$closure = function () use (static::$prop): false|null {};
+
 /* testArrowFunctionLiveCoding */
 // Intentional parse error. This has to be the last test in the file.
 $fn = fn

tests/Core/File/GetMethodPropertiesTest.php

@@ -1297,6 +1297,162 @@ public function testFunctionDeclarationNestedInTernaryPHPCS2975()
     }//end testFunctionDeclarationNestedInTernaryPHPCS2975()
 
 
+    /**
+     * Test handling of closure declarations with a use variable import without a return type declaration.
+     *
+     * @return void
+     */
+    public function testClosureWithUseNoReturnType()
+    {
+        // Offsets are relative to the T_CLOSURE token.
+        $expected = [
+            'scope'                 => 'public',
+            'scope_specified'       => false,
+            'return_type'           => '',
+            'return_type_token'     => false,
+            'return_type_end_token' => false,
+            'nullable_return_type'  => false,
+            'is_abstract'           => false,
+            'is_final'              => false,
+            'is_static'             => false,
+            'has_body'              => true,
+        ];
+
+        $this->getMethodPropertiesTestHelper('/* '.__FUNCTION__.' */', $expected);
+
+    }//end testClosureWithUseNoReturnType()
+
+
+    /**
+     * Test handling of closure declarations with a use variable import without a return type declaration.
+     *
+     * @return void
+     */
+    public function testClosureWithUseNoReturnTypeUseProp()
+    {
+        // Offsets are relative to the T_CLOSURE token.
+        $expected = [
+            'scope'                 => 'public',
+            'scope_specified'       => false,
+            'return_type'           => '',
+            'return_type_token'     => false,
+            'return_type_end_token' => false,
+            'nullable_return_type'  => false,
+            'is_abstract'           => false,
+            'is_final'              => false,
+            'is_static'             => false,
+            'has_body'              => true,
+        ];
+
+        $this->getMethodPropertiesTestHelper('/* '.__FUNCTION__.' */', $expected);
+
+    }//end testClosureWithUseNoReturnTypeUseProp()
+
+
+    /**
+     * Test handling of closure declarations with a use variable import with a return type declaration.
+     *
+     * @return void
+     */
+    public function testClosureWithUseWithReturnType()
+    {
+        // Offsets are relative to the T_CLOSURE token.
+        $expected = [
+            'scope'                 => 'public',
+            'scope_specified'       => false,
+            'return_type'           => 'Type',
+            'return_type_token'     => 14,
+            'return_type_end_token' => 14,
+            'nullable_return_type'  => false,
+            'is_abstract'           => false,
+            'is_final'              => false,
+            'is_static'             => false,
+            'has_body'              => true,
+        ];
+
+        $this->getMethodPropertiesTestHelper('/* '.__FUNCTION__.' */', $expected);
+
+    }//end testClosureWithUseWithReturnType()
+
+
+    /**
+     * Test handling of closure declarations with a use variable import with a return type declaration.
+     *
+     * @return void
+     */
+    public function testClosureWithUseWithReturnTypeUseProp()
+    {
+        // Offsets are relative to the T_CLOSURE token.
+        $expected = [
+            'scope'                 => 'public',
+            'scope_specified'       => false,
+            'return_type'           => '?array',
+            'return_type_token'     => 15,
+            'return_type_end_token' => 15,
+            'nullable_return_type'  => true,
+            'is_abstract'           => false,
+            'is_final'              => false,
+            'is_static'             => false,
+            'has_body'              => true,
+        ];
+
+        $this->getMethodPropertiesTestHelper('/* '.__FUNCTION__.' */', $expected);
+
+    }//end testClosureWithUseWithReturnTypeUseProp()
+
+
+    /**
+     * Test handling of closure declarations with a use variable import with a return type declaration.
+     *
+     * @return void
+     */
+    public function testClosureWithUseWithReturnTypeUseStaticPropWithSelf()
+    {
+        // Offsets are relative to the T_CLOSURE token.
+        $expected = [
+            'scope'                 => 'public',
+            'scope_specified'       => false,
+            'return_type'           => 'int',
+            'return_type_token'     => 13,
+            'return_type_end_token' => 13,
+            'nullable_return_type'  => false,
+            'is_abstract'           => false,
+            'is_final'              => false,
+            'is_static'             => false,
+            'has_body'              => true,
+        ];
+
+        $this->getMethodPropertiesTestHelper('/* '.__FUNCTION__.' */', $expected);
+
+    }//end testClosureWithUseWithReturnTypeUseStaticPropWithSelf()
+
+
+    /**
+     * Test handling of closure declarations with a use variable import with a return type declaration.
+     *
+     * @return void
+     */
+    public function testClosureWithUseWithReturnTypeUseStaticPropWithStatic()
+    {
+        // Offsets are relative to the T_CLOSURE token.
+        $expected = [
+            'scope'                 => 'public',
+            'scope_specified'       => false,
+            'return_type'           => 'false|null',
+            'return_type_token'     => 14,
+            'return_type_end_token' => 16,
+            'nullable_return_type'  => false,
+            'is_abstract'           => false,
+            'is_final'              => false,
+            'is_static'             => false,
+            'has_body'              => true,
+        ];
+
+        $this->getMethodPropertiesTestHelper('/* '.__FUNCTION__.' */', $expected);
+
+    }//end testClosureWithUseWithReturnTypeUseStaticPropWithStatic()
+
+
     /**
      * Test helper.
      *