Fix resolving of __DIR__, __NAMESPACE__ in traits

src/Reflection/InitializerExprTypeResolver.php

@@ -336,6 +336,13 @@ public function getType(Expr $expr, InitializerExprContext $context): Type
 		}
 
 		if ($expr instanceof MagicConst\Class_) {
+			if ($context->getTraitName() !== null) {
+				return TypeCombinator::intersect(
+					new ClassStringType(),
+					new AccessoryLiteralStringType(),
+				);
+			}
+
 			if ($context->getClassName() === null) {
 				return new ConstantStringType('');
 			}
@@ -344,6 +351,13 @@ public function getType(Expr $expr, InitializerExprContext $context): Type
 		}
 
 		if ($expr instanceof MagicConst\Namespace_) {
+			if ($context->getTraitName() !== null) {
+				return TypeCombinator::intersect(
+					new StringType(),
+					new AccessoryLiteralStringType(),
+				);
+			}
+
 			return new ConstantStringType($context->getNamespace() ?? '');
 		}
 

tests/PHPStan/Analyser/NodeScopeResolverTest.php

@@ -1174,6 +1174,7 @@ public function dataFileAsserts(): iterable
 		yield from $this->gatherAssertTypes(__DIR__ . '/data/bug-8625.php');
 		yield from $this->gatherAssertTypes(__DIR__ . '/data/bug-8621.php');
 		yield from $this->gatherAssertTypes(__DIR__ . '/data/bug-8084.php');
+		yield from $this->gatherAssertTypes(__DIR__ . '/data/bug-3019.php');
 	}
 
 	/**

tests/PHPStan/Analyser/data/bug-3019.php

@@ -0,0 +1,35 @@
+<?php
+
+namespace Bug3019;
+
+use function PHPStan\Testing\assertType;
+
+trait FooTrait
+{
+	public function doFoo(): void
+	{
+		assertType('class-string&literal-string', __CLASS__);
+		assertType('literal-string', __NAMESPACE__);
+	}
+
+	public function doFooBaz(): void
+	{
+		$key = __CLASS__ === 'Bug3019\Foo' ? 'display' : 'layout';
+	}
+}
+
+class Foo
+{
+	use FooTrait;
+
+	public function doFooBar(): void
+	{
+		assertType("'Bug3019\\\Foo'", __CLASS__);
+		assertType("'Bug3019'", __NAMESPACE__);
+	}
+}
+
+class Bar
+{
+	use FooTrait;
+}

tests/PHPStan/Rules/Comparison/UnreachableTernaryElseBranchRuleTest.php

@@ -91,4 +91,10 @@ public function testReportPhpDoc(): void
 		]);
 	}
 
+	public function testBug3019(): void
+	{
+		$this->treatPhpDocTypesAsCertain = true;
+		$this->analyse([__DIR__ . '/../../Analyser/data/bug-3019.php'], []);
+	}
+
 }