Invalidate expressions after dynamic method calls

Dynamic method calls like `$this->{'compileSection'}()` or
`$this->{$variable}()` could not be resolved to a method reflection,
so the else branch (unknown method) did not invalidate the callee
expression. Since we cannot determine what the method does, treat it
like a method with certain side effects and fully invalidate.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: phpstan-bot

src/Analyser/ExprHandler/MethodCallHandler.php

@@ -179,6 +179,8 @@ public function processExpr(NodeScopeResolver $nodeScopeResolver, Stmt $stmt, Ex
 			}
 
 		} else {
+			$nodeScopeResolver->callNodeCallback($nodeCallback, new InvalidateExprNode($normalizedExpr->var), $scope, $storage);
+			$scope = $scope->invalidateExpression($normalizedExpr->var, true);
 			$throwPoints[] = InternalThrowPoint::createImplicit($scope, $expr);
 		}
 		$hasYield = $hasYield || $argsResult->hasYield();

tests/PHPStan/Analyser/nsrt/bug-3831.php

@@ -118,3 +118,41 @@ public function test(): void
 		assertType('5', $this->x);
 	}
 }
+
+class DynamicMethodCall
+{
+	public int $counter = 0;
+
+	/** @var array<string> */
+	public array $footer = [];
+
+	public function test(): void
+	{
+		$this->counter = 0;
+		assertType('0', $this->counter);
+
+		$this->{'increment'}();
+		assertType('int', $this->counter);
+	}
+
+	public function testDynamicVar(): void
+	{
+		$this->footer = [];
+		assertType('array{}', $this->footer);
+
+		$method = 'compileSection';
+		$this->{$method}();
+		assertType('array<string>', $this->footer);
+	}
+
+	private function increment(): int
+	{
+		$this->counter++;
+		return 0;
+	}
+
+	private function compileSection(): void
+	{
+		$this->footer[] = 'section-name';
+	}
+}

tests/PHPStan/Rules/Comparison/data/bug-3831.php

@@ -61,3 +61,52 @@ private function load(): array
 		return [];
 	}
 }
+
+class Template
+{
+	/** @var array<string> */
+	public $footer = [];
+
+	public function render(): string
+	{
+		$content = '';
+		$this->footer = [];
+
+		$this->{'compileSection'}();
+
+		if (count($this->footer) > 0) {
+			$content = str_replace('some', 'thing', $content);
+		}
+		return $content;
+	}
+
+	private function compileSection(): void
+	{
+		$this->footer[] = 'section-name';
+	}
+}
+
+class TemplateDynamicVar
+{
+	/** @var array<string> */
+	public $footer = [];
+
+	public function render(): string
+	{
+		$content = '';
+		$this->footer = [];
+
+		$method = 'compileSection';
+		$this->{$method}();
+
+		if (count($this->footer) > 0) {
+			$content = str_replace('some', 'thing', $content);
+		}
+		return $content;
+	}
+
+	private function compileSection(): void
+	{
+		$this->footer[] = 'section-name';
+	}
+}