Fix phpstan/phpstan#14384: Result of function_exists() can't be "cached" (#5303)

Author: phpstan-bot

src/Analyser/ExprHandler/AssignHandler.php

@@ -10,6 +10,7 @@
 use PhpParser\Node\Expr\Assign;
 use PhpParser\Node\Expr\AssignRef;
 use PhpParser\Node\Expr\ConstFetch;
+use PhpParser\Node\Expr\FuncCall;
 use PhpParser\Node\Expr\List_;
 use PhpParser\Node\Expr\MethodCall;
 use PhpParser\Node\Expr\PropertyFetch;
@@ -863,6 +864,7 @@ private function processSureTypesForConditionalExpressionsAfterAssign(Scope $sco
 			} elseif (
 				!$expr instanceof PropertyFetch
 				&& !$expr instanceof ArrayDimFetch
+				&& !$expr instanceof FuncCall
 			) {
 				continue;
 			}
@@ -901,6 +903,7 @@ private function processSureNotTypesForConditionalExpressionsAfterAssign(Scope $
 			} elseif (
 				!$expr instanceof PropertyFetch
 				&& !$expr instanceof ArrayDimFetch
+				&& !$expr instanceof FuncCall
 			) {
 				continue;
 			}

tests/PHPStan/Rules/Functions/CallToNonExistentFunctionRuleTest.php

@@ -254,4 +254,9 @@ public function testRememberFunctionExistsFromConstructor(): void
 		]);
 	}
 
+	public function testBug14384(): void
+	{
+		$this->analyse([__DIR__ . '/data/bug-14384.php'], []);
+	}
+
 }

tests/PHPStan/Rules/Functions/data/bug-14384.php

@@ -0,0 +1,9 @@
+<?php declare(strict_types = 1);
+
+namespace Bug14384;
+
+$canCall = function_exists('some_totally_nonexistent_function_14384');
+
+if ($canCall) {
+	some_totally_nonexistent_function_14384();
+}