fix 'Call to a member function isAlias() on null', when processing Closure

[guweigang]

Hello!

• Type: bug fix
• Link to issue: fix 'Call to a member function isAlias() on null', when processing Closure #2241

In raising this pull request, I confirm the following:

• I have checked that another pull request for this purpose does not exist
• I wrote some tests for this PR
• I updated the CHANGELOG

Small description of change:

My Env:

PHP 7.4.18
Zephir 0.13.4

Because of this, zephir generate command does not generate kernel and related c-header files.

PHP Error:

[06-May-2021 10:18:26 Asia/Chongqing] PHP Fatal error:  Uncaught Error: Call to a member function isAlias() on null in /home/guweigang/.config/composer/vendor/phalcon/zephir/Library/ClassMethod.php:2449
Stack trace:
#0 /home/guweigang/.config/composer/vendor/phalcon/zephir/Library/ClassMethod.php(2408): Zephir\ClassMethod->detectClassNameEntry()
#1 /home/guweigang/.config/composer/vendor/phalcon/zephir/Library/ClassMethod.php(2067): Zephir\ClassMethod->detectParam()
#2 /home/guweigang/.config/composer/vendor/phalcon/zephir/Library/ClassDefinition.php(1283): Zephir\ClassMethod->compile()
#3 /home/guweigang/.config/composer/vendor/phalcon/zephir/Library/CompilerFileAnonymous.php(106): Zephir\ClassDefinition->compile()
#4 /home/guweigang/.config/composer/vendor/phalcon/zephir/Library/CompilerFileAnonymous.php(201): Zephir\CompilerFileAnonymous->compileClass()
#5 /home/guweigang/.config/composer/vendor/phalcon/zephir/Library/Compiler.php(736): Zephir\CompilerFileAnonymous->compile()
#6 /home/guweigang/.config/composer/vendor/phalcon/zephir/Library/Console/Command/Gene in /home/guweigang/.config/composer/vendor/phalcon/zephir/Library/ClassMethod.php on line 2449

I debuged this, and get:

/home/guweigang/.config/composer/vendor/phalcon/zephir/Library/ClassMethod.php:2450:
string(9) "\Iterator"
/home/guweigang/.config/composer/vendor/phalcon/zephir/Library/ClassMethod.php:2450:
class Zephir\ClassDefinition#7285 (23) {
  protected string $namespace =>
  string(11) "phalconplus"
  protected string $shortName =>
  string(10) "2__closure"
  protected string $type =>
  string(5) "class"
  protected ?string $extendsClass =>
  ....

Thanks

[codecov]

Codecov Report

Merging #2241 (80029c4) into development (8d3141c) will decrease coverage by 0.00%.
The diff coverage is 0.00%.

@@               Coverage Diff                @@
##             development   #2241      +/-   ##
================================================
- Coverage           7.67%   7.67%   -0.01%     
- Complexity          8702    8703       +1     
================================================
  Files                355     355              
  Lines              22061   22063       +2     
================================================
  Hits                1694    1694              
- Misses             20367   20369       +2