Do not generalize template types in @template-covariant

phpstan · Dec 12, 2023 · dc14cb6 · dc14cb6
1 parent 7c83225
commit dc14cb6
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Showing 4 changed files with 44 additions and 11 deletions.
diff --git a/src/Analyser/MutatingScope.php b/src/Analyser/MutatingScope.php
@@ -5063,11 +5063,13 @@ private function exactInstantiation(New_ $node, string $className): ?Type
 						return $type->getBound();
 					}
 
-					$isArrayKey = $type->getBound()->describe(VerbosityLevel::precise()) === '(int|string)';
-					if ($newType->isScalar()->yes() && !$type->getVariance()->covariant() && $isArrayKey) {
-						$newType = $newType->generalize(GeneralizePrecision::templateArgument());
-					} elseif ($newType->isConstantValue()->yes() && (!$type->getBound()->isScalar()->yes() || $isArrayKey)) {
-						$newType = $newType->generalize(GeneralizePrecision::templateArgument());
+					if (!$type->getVariance()->covariant()) {
+						$isArrayKey = $type->getBound()->describe(VerbosityLevel::precise()) === '(int|string)';
+						if ($newType->isScalar()->yes() && $isArrayKey) {
+							$newType = $newType->generalize(GeneralizePrecision::templateArgument());
+						} elseif ($newType->isConstantValue()->yes() && (!$type->getBound()->isScalar()->yes() || $isArrayKey)) {
+							$newType = $newType->generalize(GeneralizePrecision::templateArgument());
+						}
 					}
 
 					return $newType;

diff --git a/src/Reflection/ResolvedFunctionVariant.php b/src/Reflection/ResolvedFunctionVariant.php
@@ -184,11 +184,13 @@ private function resolveResolvableTemplateTypes(Type $type, TemplateTypeVariance
 					return $traverse($type);
 				}
 
-				$isArrayKey = $type->getBound()->describe(VerbosityLevel::precise()) === '(int|string)';
-				if ($newType->isScalar()->yes() && !$type->getVariance()->covariant() && $isArrayKey) {
-					$newType = $newType->generalize(GeneralizePrecision::templateArgument());
-				} elseif ($newType->isConstantValue()->yes() && (!$type->getBound()->isScalar()->yes() || $isArrayKey)) {
-					$newType = $newType->generalize(GeneralizePrecision::templateArgument());
+				if (!$type->getVariance()->covariant()) {
+					$isArrayKey = $type->getBound()->describe(VerbosityLevel::precise()) === '(int|string)';
+					if ($newType->isScalar()->yes() && $isArrayKey) {
+						$newType = $newType->generalize(GeneralizePrecision::templateArgument());
+					} elseif ($newType->isConstantValue()->yes() && (!$type->getBound()->isScalar()->yes() || $isArrayKey)) {
+						$newType = $newType->generalize(GeneralizePrecision::templateArgument());
+					}
 				}
 
 				$variance = TemplateTypeVariance::createInvariant();

diff --git a/tests/PHPStan/Analyser/data/bug-7078.php b/tests/PHPStan/Analyser/data/bug-7078.php
@@ -33,5 +33,5 @@ public function get(TypeDefault ...$type);
 
 function (Param $p) {
 	$result = $p->get(new TypeDefault(1), new TypeDefault('a'));
-	assertType('int|string', $result);
+	assertType('1|\'a\'', $result);
 };
diff --git a/tests/PHPStan/Analyser/data/generics-do-not-generalize.php b/tests/PHPStan/Analyser/data/generics-do-not-generalize.php
@@ -117,3 +117,32 @@ function (): void {
 
 	assertType('ArrayIterator<int, string>', createArrayIterator($a));
 };
+
+/** @template T */
+class FooInvariant
+{
+
+	/** @param T $p */
+	public function __construct($p)
+	{
+
+	}
+
+}
+
+/** @template-covariant T */
+class FooCovariant
+{
+
+	/** @param T $p */
+	public function __construct($p)
+	{
+
+	}
+
+}
+
+function (): void {
+	assertType('GenericsDoNotGeneralize\\FooInvariant<int>', new FooInvariant(1));
+	assertType('GenericsDoNotGeneralize\\FooCovariant<1>', new FooCovariant(1));
+};