Optimize native function and constant calls

README.md

@@ -45,6 +45,7 @@ potentially very difficult to debug due to dissimilar or unsupported package ver
 - [Limitations](#limitations)
     - [PSR-0 support](#psr-0-support)
     - [String values](#string-values)
+    - [Native functions and constants shadowing](#native-functions-shadowing)
 - [Contributing](#contributing)
 - [Credits](#credits)
 
@@ -437,6 +438,41 @@ bound to have confusing cases. For example:
   name or a random string.
 
 
+### Native functions and constants shadowing
+
+In the following example:
+
+```php
+<?php
+
+namespace Foo;
+
+is_array([]);
+
+```
+
+No use statement is used for the function `is_array`. This means that PHP will try to load the function `\Foo\is_array`
+and if fails to do so will fallback on `\is_array` (note that PHP does so only for functions and constants: not classes).
+
+In order to bring some performance optimisation, the call will nonetheless be prefixed in `\is_array`. This *will* break
+your code if you were relying on `\Foo\is_array` instead. This however should be _extremely_ rare, so if that happens
+you have two solutions: use a [patcher](#patchers) or simpler remove any ambiguity by making use of a use statement
+(which is unneeded outside of the context of prefixing your code):
+
+```php
+<?php
+
+namespace Foo;
+
+use function Foo\is_array;
+
+is_array([]);
+
+```
+
+The situation is exactly the same for constants.
+
+
 ## Contributing
 
 [Contribution Guide](CONTRIBUTING.md)

scoper.inc.php

@@ -44,21 +44,12 @@ function (string $filePath, string $prefix, string $contents): string {
             //
             // PHP-Parser patch
             //
-
-            if ($filePath === __DIR__.'/vendor/nikic/php-parser/lib/PhpParser/Lexer.php') {
-                return preg_replace(
-                    '%if \(defined\(\$name = \'PhpParser\\\\\\\\Parser\\\\\\\\Tokens%',
-                    'if (defined($name = \''.$prefix.'\\\\\\\\PhpParser\\\\\\\\Parser\\\\\\\\Tokens',
-                    $contents
-                );
-            }
-
             if ($filePath === realpath(__DIR__.'/vendor/nikic/php-parser/lib/PhpParser/NodeAbstract.php')) {
                 $length = 15 + strlen($prefix) + 1;
 
                 return preg_replace(
-                    '%rtrim\(get_class\(\$this\), \'_\'\), 15\)%',
-                    sprintf('rtrim(get_class($this), \'_\'), %d)', $length),
+                    '%strpos\((.+?)\) \+ 15%',
+                    sprintf('strpos($1) + %d', $length),
                     $contents
                 );
             }

specs/class-FQ.php

@@ -78,13 +78,13 @@ class Foo
 class Bar
 {
 }
-class_alias('Humbug\\Foo\\Bar', 'Foo\\Bar', \false);
+\class_alias('Humbug\\Foo\\Bar', 'Foo\\Bar', \false);
 namespace Humbug\Foo\Bar;
 
 class Poz
 {
 }
-class_alias('Humbug\\Foo\\Bar\\Poz', 'Foo\\Bar\\Poz', \false);
+\class_alias('Humbug\\Foo\\Bar\\Poz', 'Foo\\Bar\\Poz', \false);
 namespace Humbug;
 
 use Humbug\Foo as X;
@@ -279,47 +279,47 @@ class Foo
 class Bar
 {
 }
-class_alias('Humbug\\Foo\\Bar', 'Foo\\Bar', \false);
+\class_alias('Humbug\\Foo\\Bar', 'Foo\\Bar', \false);
 namespace Humbug\Foo\Bar;
 
 class Poz
 {
 }
-class_alias('Humbug\\Foo\\Bar\\Poz', 'Foo\\Bar\\Poz', \false);
+\class_alias('Humbug\\Foo\\Bar\\Poz', 'Foo\\Bar\\Poz', \false);
 namespace Humbug\A;
 
 class Aoo
 {
 }
-class_alias('Humbug\\A\\Aoo', 'A\\Aoo', \false);
+\class_alias('Humbug\\A\\Aoo', 'A\\Aoo', \false);
 class Foo
 {
 }
-class_alias('Humbug\\A\\Foo', 'A\\Foo', \false);
+\class_alias('Humbug\\A\\Foo', 'A\\Foo', \false);
 namespace Humbug\A\Foo;
 
 class Bar
 {
 }
-class_alias('Humbug\\A\\Foo\\Bar', 'A\\Foo\\Bar', \false);
+\class_alias('Humbug\\A\\Foo\\Bar', 'A\\Foo\\Bar', \false);
 namespace Humbug\A\Foo\Bar;
 
 class Poz
 {
 }
-class_alias('Humbug\\A\\Foo\\Bar\\Poz', 'A\\Foo\\Bar\\Poz', \false);
+\class_alias('Humbug\\A\\Foo\\Bar\\Poz', 'A\\Foo\\Bar\\Poz', \false);
 namespace Humbug\A\Aoo;
 
 class Aoz
 {
 }
-class_alias('Humbug\\A\\Aoo\\Aoz', 'A\\Aoo\\Aoz', \false);
+\class_alias('Humbug\\A\\Aoo\\Aoz', 'A\\Aoo\\Aoz', \false);
 namespace Humbug\A\Aoo\Aoz;
 
 class Poz
 {
 }
-class_alias('Humbug\\A\\Aoo\\Aoz\\Poz', 'A\\Aoo\\Aoz\\Poz', \false);
+\class_alias('Humbug\\A\\Aoo\\Aoz\\Poz', 'A\\Aoo\\Aoz\\Poz', \false);
 namespace Humbug\A;
 
 use Humbug\Foo as X;

specs/class-const/global-scope-two-level-with-single-level-use-and-alias.php

@@ -179,7 +179,7 @@ class Foo
 class Bar
 {
 }
-class_alias('Humbug\\Foo\\Bar', 'Foo\\Bar', \false);
+\class_alias('Humbug\\Foo\\Bar', 'Foo\\Bar', \false);
 namespace Humbug;
 
 use Humbug\Foo as X;

specs/class-const/global-scope-two-level-with-single-level-use.php

@@ -189,7 +189,7 @@ class Foo
 class Bar
 {
 }
-class_alias('Humbug\\Foo\\Bar', 'Foo\\Bar', \false);
+\class_alias('Humbug\\Foo\\Bar', 'Foo\\Bar', \false);
 namespace Humbug;
 
 use Humbug\Foo;
@@ -235,7 +235,7 @@ class Foo
 class Bar
 {
 }
-class_alias('Humbug\\Foo\\Bar', 'Foo\\Bar', \false);
+\class_alias('Humbug\\Foo\\Bar', 'Foo\\Bar', \false);
 namespace Humbug;
 
 use Humbug\Foo;

specs/class-const/global-scope-two-level.php

@@ -110,7 +110,7 @@ class Command {}
 class Command
 {
 }
-class_alias('Humbug\\PHPUnit\\Command', 'PHPUnit\\Command', \false);
+\class_alias('Humbug\\PHPUnit\\Command', 'PHPUnit\\Command', \false);
 namespace Humbug;
 
 \Humbug\PHPUnit\Command::MAIN_CONST;
@@ -144,7 +144,7 @@ class Command {}
 class Command
 {
 }
-class_alias('Humbug\\PHPUnit\\Command', 'PHPUnit\\Command', \false);
+\class_alias('Humbug\\PHPUnit\\Command', 'PHPUnit\\Command', \false);
 namespace Humbug;
 
 \Humbug\PHPUnit\Command::MAIN_CONST;

specs/class-const/namespace-scope-two-level-with-single-level-use-and-alias.php

@@ -183,7 +183,7 @@ class Foo
 class Bar
 {
 }
-class_alias('Humbug\\Foo\\Bar', 'Foo\\Bar', \false);
+\class_alias('Humbug\\Foo\\Bar', 'Foo\\Bar', \false);
 namespace Humbug\A;
 
 use Humbug\Foo as X;

specs/class-const/namespace-scope-two-level-with-single-level-use.php

@@ -193,7 +193,7 @@ class Foo
 class Bar
 {
 }
-class_alias('Humbug\\Foo\\Bar', 'Foo\\Bar', \false);
+\class_alias('Humbug\\Foo\\Bar', 'Foo\\Bar', \false);
 namespace Humbug\X;
 
 use Humbug\Foo;
@@ -240,7 +240,7 @@ class Foo
 class Bar
 {
 }
-class_alias('Humbug\\Foo\\Bar', 'Foo\\Bar', \false);
+\class_alias('Humbug\\Foo\\Bar', 'Foo\\Bar', \false);
 namespace Humbug\X;
 
 use Humbug\Foo;

specs/class-const/namespace-scope-two-level.php

@@ -113,7 +113,7 @@ class Command {}
 class Command
 {
 }
-class_alias('Humbug\\X\\PHPUnit\\Command', 'X\\PHPUnit\\Command', \false);
+\class_alias('Humbug\\X\\PHPUnit\\Command', 'X\\PHPUnit\\Command', \false);
 namespace Humbug\X;
 
 \Humbug\X\PHPUnit\Command::MAIN_CONST;
@@ -148,7 +148,7 @@ class Command {}
 class Command
 {
 }
-class_alias('Humbug\\PHPUnit\\Command', 'PHPUnit\\Command', \false);
+\class_alias('Humbug\\PHPUnit\\Command', 'PHPUnit\\Command', \false);
 namespace Humbug\X;
 
 \Humbug\PHPUnit\Command::MAIN_CONST;

specs/class/abstract.php

@@ -91,7 +91,7 @@ public function a()
     }
     public abstract function b();
 }
-class_alias('Humbug\\Foo\\A', 'Foo\\A', \false);
+\class_alias('Humbug\\Foo\\A', 'Foo\\A', \false);
 
 PHP
         ],
@@ -154,7 +154,7 @@ public function a()
     {
     }
 }
-class_alias('Humbug\\Foo\\WA', 'Foo\\WA', \false);
+\class_alias('Humbug\\Foo\\WA', 'Foo\\WA', \false);
 namespace Humbug\Bar;
 
 abstract class B
@@ -169,7 +169,7 @@ public function b()
     {
     }
 }
-class_alias('Humbug\\Bar\\WB', 'Bar\\WB', \false);
+\class_alias('Humbug\\Bar\\WB', 'Bar\\WB', \false);
 namespace Humbug;
 
 abstract class C

specs/class/conditional.php

@@ -83,7 +83,7 @@ class A {}
 
 namespace Humbug\Foo;
 
-if (true) {
+if (\true) {
     class A
     {
     }
@@ -107,7 +107,7 @@ class A {}
 
 namespace Humbug\Foo;
 
-if (true) {
+if (\true) {
     class A
     {
     }
@@ -141,21 +141,21 @@ class C {}
 
 namespace Humbug\X;
 
-if (true) {
+if (\true) {
     class A
     {
     }
 }
 namespace Humbug\Y;
 
-if (true) {
+if (\true) {
     class B
     {
     }
 }
 namespace Humbug\Z;
 
-if (true) {
+if (\true) {
     class C
     {
     }

specs/class/final.php

@@ -70,7 +70,7 @@ final class A {}
 final class A
 {
 }
-class_alias('Humbug\\Foo\\A', 'Foo\\A', \false);
+\class_alias('Humbug\\Foo\\A', 'Foo\\A', \false);
 
 PHP
         ],

specs/class/interface.php

@@ -114,7 +114,7 @@ interface A extends \Humbug\Foo\C, \Humbug\Foo\D, \Iterator
 {
     public function a();
 }
-class_alias('Humbug\\Foo\\A', 'Foo\\A', \false);
+\class_alias('Humbug\\Foo\\A', 'Foo\\A', \false);
 
 PHP
         ],

specs/class/regular-extend.php

@@ -106,7 +106,7 @@ public function a()
 class B extends \Humbug\Foo\A
 {
 }
-class_alias('Humbug\\Foo\\B', 'Foo\\B', \false);
+\class_alias('Humbug\\Foo\\B', 'Foo\\B', \false);
 
 PHP
         ],

specs/class/regular.php

@@ -85,7 +85,7 @@ public function a()
     {
     }
 }
-class_alias('Humbug\\Foo\\A', 'Foo\\A', \false);
+\class_alias('Humbug\\Foo\\A', 'Foo\\A', \false);
 
 PHP
         ],
@@ -207,7 +207,7 @@ public function a()
     {
     }
 }
-class_alias('Humbug\\Foo\\A', 'Foo\\A', \false);
+\class_alias('Humbug\\Foo\\A', 'Foo\\A', \false);
 class B
 {
     public function b()
@@ -234,7 +234,7 @@ public function b()
     {
     }
 }
-class_alias('Humbug\\Bar\\B', 'Bar\\B', \false);
+\class_alias('Humbug\\Bar\\B', 'Bar\\B', \false);
 class C
 {
     public function c()