Implement template default types

src/Analyser/MutatingScope.php

@@ -2539,6 +2539,7 @@ private function createFirstClassCallable(
 				$templateTags[$templateType->getName()] = new TemplateTag(
 					$templateType->getName(),
 					$templateType->getBound(),
+					$templateType->getDefault(),
 					$templateType->getVariance(),
 				);
 			}
@@ -5606,6 +5607,11 @@ private function exactInstantiation(New_ $node, string $className): ?Type
 				$list[] = $templateType;
 				continue;
 			}
+			$default = $tag->getDefault();
+			if ($default !== null) {
+				$list[] = $default;
+				continue;
+			}
 			$bound = $tag->getBound();
 			if ($bound instanceof MixedType && $bound->isExplicitMixed()) {
 				$bound = new MixedType(false);

src/Dependency/DependencyResolver.php

@@ -531,6 +531,17 @@ private function addClassToDependencies(string $className, array &$dependenciesR
 					}
 					$dependenciesReflections[] = $this->reflectionProvider->getClass($referencedClass);
 				}
+
+				$default = $templateTag->getDefault();
+				if ($default === null) {
+					continue;
+				}
+				foreach ($default->getReferencedClasses() as $referencedClass) {
+					if (!$this->reflectionProvider->hasClass($referencedClass)) {
+						continue;
+					}
+					$dependenciesReflections[] = $this->reflectionProvider->getClass($referencedClass);
+				}
 			}
 
 			foreach ($classReflection->getPropertyTags() as $propertyTag) {

src/PhpDoc/PhpDocNodeResolver.php

@@ -176,6 +176,9 @@ public function resolveMethodTags(PhpDocNode $phpDocNode, NameScope $nameScope):
 							$templateType->bound !== null
 								? $this->typeNodeResolver->resolve($templateType->bound, $nameScope)
 								: new MixedType(),
+							$templateType->default !== null
+								? $this->typeNodeResolver->resolve($templateType->default, $nameScope)
+								: null,
 							TemplateTypeVariance::createInvariant(),
 						);
 					}
@@ -327,9 +330,12 @@ public function resolveTemplateTags(PhpDocNode $phpDocNode, NameScope $nameScope
 				}
 			}
 
+			$nameScopeWithoutCurrent = $nameScope->unsetTemplateType($valueNode->name);
+
 			$resolved[$valueNode->name] = new TemplateTag(
 				$valueNode->name,
-				$valueNode->bound !== null ? $this->typeNodeResolver->resolve($valueNode->bound, $nameScope->unsetTemplateType($valueNode->name)) : new MixedType(true),
+				$valueNode->bound !== null ? $this->typeNodeResolver->resolve($valueNode->bound, $nameScopeWithoutCurrent) : new MixedType(true),
+				$valueNode->default !== null ? $this->typeNodeResolver->resolve($valueNode->default, $nameScopeWithoutCurrent) : null,
 				$variance,
 			);
 			$resolvedPrefix[$valueNode->name] = $prefix;

src/PhpDoc/Tag/TemplateTag.php

@@ -15,7 +15,7 @@ class TemplateTag
 	/**
 	 * @param non-empty-string $name
 	 */
-	public function __construct(private string $name, private Type $bound, private TemplateTypeVariance $variance)
+	public function __construct(private string $name, private Type $bound, private ?Type $default, private TemplateTypeVariance $variance)
 	{
 	}
 
@@ -32,6 +32,11 @@ public function getBound(): Type
 		return $this->bound;
 	}
 
+	public function getDefault(): ?Type
+	{
+		return $this->default;
+	}
+
 	public function getVariance(): TemplateTypeVariance
 	{
 		return $this->variance;

src/PhpDoc/TypeNodeResolver.php

@@ -106,6 +106,7 @@
 use Traversable;
 use function array_key_exists;
 use function array_map;
+use function array_values;
 use function count;
 use function explode;
 use function get_class;
@@ -792,6 +793,15 @@ static function (string $variance): TemplateTypeVariance {
 
 			$classReflection = $this->getReflectionProvider()->getClass($mainTypeClassName);
 			if ($classReflection->isGeneric()) {
+				$templateTypes = array_values($classReflection->getTemplateTypeMap()->getTypes());
+				for ($i = count($genericTypes), $templateTypesCount = count($templateTypes); $i < $templateTypesCount; $i++) {
+					$templateType = $templateTypes[$i];
+					if (!$templateType instanceof TemplateType || $templateType->getDefault() === null) {
+						continue;
+					}
+					$genericTypes[] = $templateType->getDefault();
+				}
+
 				if (in_array($mainTypeClassName, [
 					Traversable::class,
 					IteratorAggregate::class,
@@ -910,6 +920,9 @@ private function resolveCallableTypeNode(CallableTypeNode $typeNode, NameScope $
 					$templateType->bound !== null
 						? $this->resolve($templateType->bound, $nameScope)
 						: new MixedType(),
+					$templateType->default !== null
+						? $this->resolve($templateType->default, $nameScope)
+						: null,
 					TemplateTypeVariance::createInvariant(),
 				);
 			}

src/Reflection/ClassReflection.php

@@ -1442,7 +1442,7 @@ public function typeMapFromList(array $types): TemplateTypeMap
 		$map = [];
 		$i = 0;
 		foreach ($resolvedPhpDoc->getTemplateTags() as $tag) {
-			$map[$tag->getName()] = $types[$i] ?? $tag->getBound();
+			$map[$tag->getName()] = $types[$i] ?? $tag->getDefault() ?? $tag->getBound();
 			$i++;
 		}
 
@@ -1479,7 +1479,7 @@ public function typeMapToList(TemplateTypeMap $typeMap): array
 
 		$list = [];
 		foreach ($resolvedPhpDoc->getTemplateTags() as $tag) {
-			$list[] = $typeMap->getType($tag->getName()) ?? $tag->getBound();
+			$list[] = $typeMap->getType($tag->getName()) ?? $tag->getDefault() ?? $tag->getBound();
 		}
 
 		return $list;

src/Rules/Classes/LocalTypeAliasesCheck.php

@@ -24,7 +24,6 @@
 use PHPStan\Type\VerbosityLevel;
 use function array_key_exists;
 use function array_merge;
-use function implode;
 use function in_array;
 use function sprintf;
 
@@ -211,7 +210,7 @@ public function checkInTraitDefinitionContext(ClassReflection $reflection): arra
 					$reflection->getDisplayName(),
 					$aliasName,
 					$name,
-					implode(', ', $genericTypeNames),
+					$genericTypeNames,
 				))
 					->identifier('missingType.generics')
 					->build();

src/Rules/Classes/MethodTagCheck.php

@@ -16,7 +16,6 @@
 use PHPStan\Type\Type;
 use PHPStan\Type\VerbosityLevel;
 use function array_merge;
-use function implode;
 use function sprintf;
 
 final class MethodTagCheck
@@ -174,7 +173,7 @@ private function checkMethodTypeInTraitDefinitionContext(ClassReflection $classR
 				$methodName,
 				$description,
 				$innerName,
-				implode(', ', $genericTypeNames),
+				$genericTypeNames,
 			))
 				->identifier('missingType.generics')
 				->build();

src/Rules/Classes/MixinCheck.php

@@ -14,7 +14,6 @@
 use PHPStan\Rules\RuleErrorBuilder;
 use PHPStan\Type\VerbosityLevel;
 use function array_merge;
-use function implode;
 use function sprintf;
 
 final class MixinCheck
@@ -90,7 +89,7 @@ public function checkInTraitDefinitionContext(ClassReflection $classReflection):
 				$errors[] = RuleErrorBuilder::message(sprintf(
 					'PHPDoc tag @mixin contains generic %s but does not specify its types: %s',
 					$innerName,
-					implode(', ', $genericTypeNames),
+					$genericTypeNames,
 				))
 					->identifier('missingType.generics')
 					->build();

src/Rules/Classes/PropertyTagCheck.php

@@ -18,7 +18,6 @@
 use PHPStan\Type\Type;
 use PHPStan\Type\VerbosityLevel;
 use function array_merge;
-use function implode;
 use function sprintf;
 
 final class PropertyTagCheck
@@ -155,7 +154,7 @@ private function checkPropertyTypeInTraitDefinitionContext(ClassReflection $clas
 				$classReflection->getDisplayName(),
 				$propertyName,
 				$innerName,
-				implode(', ', $genericTypeNames),
+				$genericTypeNames,
 			))
 				->identifier('missingType.generics')
 				->build();

src/Rules/Constants/MissingClassConstantTypehintRule.php

@@ -12,7 +12,6 @@
 use PHPStan\ShouldNotHappenException;
 use PHPStan\Type\VerbosityLevel;
 use function array_merge;
-use function implode;
 use function sprintf;
 
 /**
@@ -76,7 +75,7 @@ private function processSingleConstant(ClassReflection $classReflection, string
 				$constantReflection->getDeclaringClass()->getDisplayName(),
 				$constantName,
 				$name,
-				implode(', ', $genericTypeNames),
+				$genericTypeNames,
 			))
 				->identifier('missingType.generics')
 				->build();

src/Rules/FunctionCallParametersCheck.php

@@ -432,7 +432,7 @@ static function (Type $type, callable $traverse) use (&$returnTemplateTypes): Ty
 							$type = $type->resolve();
 						}
 
-						if ($type instanceof TemplateType) {
+						if ($type instanceof TemplateType && $type->getDefault() === null) {
 							$returnTemplateTypes[$type->getName()] = true;
 							return $type;
 						}
@@ -444,7 +444,7 @@ static function (Type $type, callable $traverse) use (&$returnTemplateTypes): Ty
 				$parameterTemplateTypes = [];
 				foreach ($originalParametersAcceptor->getParameters() as $parameter) {
 					TypeTraverser::map($parameter->getType(), static function (Type $type, callable $traverse) use (&$parameterTemplateTypes): Type {
-						if ($type instanceof TemplateType) {
+						if ($type instanceof TemplateType && $type->getDefault() === null) {
 							$parameterTemplateTypes[$type->getName()] = true;
 							return $type;
 						}

src/Rules/Functions/MissingFunctionParameterTypehintRule.php

@@ -13,7 +13,6 @@
 use PHPStan\Type\MixedType;
 use PHPStan\Type\Type;
 use PHPStan\Type\VerbosityLevel;
-use function implode;
 use function sprintf;
 
 /**
@@ -100,7 +99,7 @@ private function checkFunctionParameter(FunctionReflection $functionReflection,
 				$functionReflection->getName(),
 				$parameterMessage,
 				$name,
-				implode(', ', $genericTypeNames),
+				$genericTypeNames,
 			))
 				->identifier('missingType.generics')
 				->build();

src/Rules/Functions/MissingFunctionReturnTypehintRule.php

@@ -10,7 +10,6 @@
 use PHPStan\Rules\RuleErrorBuilder;
 use PHPStan\Type\MixedType;
 use PHPStan\Type\VerbosityLevel;
-use function implode;
 use function sprintf;
 
 /**
@@ -58,7 +57,7 @@ public function processNode(Node $node, Scope $scope): array
 				'Function %s() return type with generic %s does not specify its types: %s',
 				$functionReflection->getName(),
 				$name,
-				implode(', ', $genericTypeNames),
+				$genericTypeNames,
 			))
 				->identifier('missingType.generics')
 				->build();

src/Rules/Generics/ClassTemplateTypeRule.php

@@ -49,6 +49,9 @@ public function processNode(Node $node, Scope $scope): array
 			sprintf('PHPDoc tag @template for %s cannot have existing type alias %%s as its name.', $displayName),
 			sprintf('PHPDoc tag @template %%s for %s has invalid bound type %%s.', $displayName),
 			sprintf('PHPDoc tag @template %%s for %s with bound type %%s is not supported.', $displayName),
+			sprintf('PHPDoc tag @template %%s for %s has invalid default type %%s.', $displayName),
+			sprintf('Default type %%s in PHPDoc tag @template %%s for %s is not subtype of bound type %%s.', $displayName),
+			sprintf('PHPDoc tag @template %%s for %s does not have a default type but follows an optional @template %%s.', $displayName),
 		);
 	}
 

src/Rules/Generics/FunctionTemplateTypeRule.php

@@ -60,6 +60,9 @@ public function processNode(Node $node, Scope $scope): array
 			sprintf('PHPDoc tag @template for function %s() cannot have existing type alias %%s as its name.', $escapedFunctionName),
 			sprintf('PHPDoc tag @template %%s for function %s() has invalid bound type %%s.', $escapedFunctionName),
 			sprintf('PHPDoc tag @template %%s for function %s() with bound type %%s is not supported.', $escapedFunctionName),
+			sprintf('PHPDoc tag @template %%s for function %s() has invalid default type %%s.', $escapedFunctionName),
+			sprintf('Default type %%s in PHPDoc tag @template %%s for function %s() is not subtype of bound type %%s.', $escapedFunctionName),
+			sprintf('PHPDoc tag @template %%s for function %s() does not have a default type but follows an optional @template %%s.', $escapedFunctionName),
 		);
 	}
 

src/Rules/Generics/GenericAncestorsCheck.php

@@ -9,11 +9,13 @@
 use PHPStan\Rules\PhpDoc\UnresolvableTypeHelper;
 use PHPStan\Rules\RuleErrorBuilder;
 use PHPStan\Type\Generic\GenericObjectType;
+use PHPStan\Type\Generic\TemplateType;
 use PHPStan\Type\Generic\TemplateTypeVariance;
 use PHPStan\Type\Generic\TypeProjectionHelper;
 use PHPStan\Type\Type;
 use PHPStan\Type\VerbosityLevel;
 use function array_fill_keys;
+use function array_filter;
 use function array_keys;
 use function array_map;
 use function array_merge;
@@ -173,10 +175,22 @@ public function check(
 					continue;
 				}
 
+				$templateTypes = $unusedNameClassReflection->getTemplateTypeMap()->getTypes();
+				$templateTypesCount = count($templateTypes);
+				$requiredTemplateTypesCount = count(array_filter($templateTypes, static fn (Type $type) => $type instanceof TemplateType && $type->getDefault() === null));
+				if ($requiredTemplateTypesCount === 0) {
+					continue;
+				}
+
+				$templateTypesList = implode(', ', array_keys($templateTypes));
+				if ($requiredTemplateTypesCount !== $templateTypesCount) {
+					$templateTypesList .= sprintf(' (%d-%d required)', $requiredTemplateTypesCount, $templateTypesCount);
+				}
+
 				$messages[] = RuleErrorBuilder::message(sprintf(
 					$genericClassInNonGenericObjectType,
 					$unusedName,
-					implode(', ', array_keys($unusedNameClassReflection->getTemplateTypeMap()->getTypes())),
+					$templateTypesList,
 				))
 					->identifier('missingType.generics')
 					->build();

src/Rules/Generics/GenericObjectTypeCheck.php

@@ -14,6 +14,7 @@
 use PHPStan\Type\Type;
 use PHPStan\Type\TypeTraverser;
 use PHPStan\Type\VerbosityLevel;
+use function array_filter;
 use function array_keys;
 use function array_values;
 use function count;
@@ -59,27 +60,37 @@ public function check(
 			$genericTypeVariances = $genericType->getVariances();
 			$templateTypesCount = count($templateTypes);
 			$genericTypeTypesCount = count($genericTypeTypes);
-			if ($templateTypesCount > $genericTypeTypesCount) {
+			$requiredTemplateTypesCount = count(array_filter($templateTypes, static fn (Type $type) => $type instanceof TemplateType && $type->getDefault() === null));
+			if ($requiredTemplateTypesCount > $genericTypeTypesCount) {
+				$templateTypesList = implode(', ', array_keys($classReflection->getTemplateTypeMap()->getTypes()));
+				if ($requiredTemplateTypesCount !== $templateTypesCount) {
+					$templateTypesList .= sprintf(' (%d-%d required).', $requiredTemplateTypesCount, $templateTypesCount);
+				}
+
 				$messages[] = RuleErrorBuilder::message(sprintf(
 					$notEnoughTypesMessage,
 					$genericType->describe(VerbosityLevel::typeOnly()),
 					$classLikeDescription,
 					$classReflection->getDisplayName(false),
-					implode(', ', array_keys($classReflection->getTemplateTypeMap()->getTypes())),
+					$templateTypesList,
 				))->identifier('generics.lessTypes')->build();
 			} elseif ($templateTypesCount < $genericTypeTypesCount) {
+				$templateTypesList = implode(', ', array_keys($classReflection->getTemplateTypeMap()->getTypes()));
+				if ($requiredTemplateTypesCount !== $templateTypesCount) {
+					$templateTypesList .= sprintf(' (%d-%d required)', $requiredTemplateTypesCount, $templateTypesCount);
+				}
+
 				$messages[] = RuleErrorBuilder::message(sprintf(
 					$extraTypesMessage,
 					$genericType->describe(VerbosityLevel::typeOnly()),
 					$genericTypeTypesCount,
 					$classLikeDescription,
 					$classReflection->getDisplayName(false),
 					$templateTypesCount,
-					implode(', ', array_keys($classReflection->getTemplateTypeMap()->getTypes())),
+					$templateTypesList,
 				))->identifier('generics.moreTypes')->build();
 			}
 
-			$templateTypesCount = count($templateTypes);
 			for ($i = 0; $i < $templateTypesCount; $i++) {
 				if (!isset($genericTypeTypes[$i])) {
 					continue;

src/Rules/Generics/InterfaceTemplateTypeRule.php

@@ -46,6 +46,9 @@ public function processNode(Node $node, Scope $scope): array
 			sprintf('PHPDoc tag @template for interface %s cannot have existing type alias %%s as its name.', $escapadInterfaceName),
 			sprintf('PHPDoc tag @template %%s for interface %s has invalid bound type %%s.', $escapadInterfaceName),
 			sprintf('PHPDoc tag @template %%s for interface %s with bound type %%s is not supported.', $escapadInterfaceName),
+			sprintf('PHPDoc tag @template %%s for interface %s has invalid default type %%s.', $escapadInterfaceName),
+			sprintf('Default type %%s in PHPDoc tag @template %%s for interface %s is not subtype of bound type %%s.', $escapadInterfaceName),
+			sprintf('PHPDoc tag @template %%s for interface %s does not have a default type but follows an optional @template %%s.', $escapadInterfaceName),
 		);
 	}
 

src/Rules/Generics/MethodTagTemplateTypeCheck.php

@@ -61,6 +61,9 @@ public function check(
 				sprintf('PHPDoc tag @method template for method %s::%s() cannot have existing type alias %%s as its name.', $escapedClassName, $escapedMethodName),
 				sprintf('PHPDoc tag @method template %%s for method %s::%s() has invalid bound type %%s.', $escapedClassName, $escapedMethodName),
 				sprintf('PHPDoc tag @method template %%s for method %s::%s() with bound type %%s is not supported.', $escapedClassName, $escapedMethodName),
+				sprintf('PHPDoc tag @method template %%s for method %s::%s() has invalid default type %%s', $escapedClassName, $escapedMethodName),
+				sprintf('Default type %%s in PHPDoc tag @method template %%s for method %s::%s() is not subtype of bound type %%s', $escapedClassName, $escapedMethodName),
+				sprintf('PHPDoc tag @template %%s for method %s::%s() does not have a default type but follows an optional @template %%s.', $escapedClassName, $escapedMethodName),
 			));
 
 			foreach (array_keys($methodTemplateTags) as $name) {