Early termination for NeverType match expression

phpstan · Mar 22, 2022 · 99951ac · 99951ac
1 parent c564943
commit 99951ac
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Showing 16 changed files with 156 additions and 27 deletions.
diff --git a/src/Type/Accessory/HasMethodType.php b/src/Type/Accessory/HasMethodType.php
@@ -62,6 +62,10 @@ public function isSubTypeOf(Type $otherType): TrinaryLogic
 			return $otherType->isSuperTypeOf($this);
 		}
 
+		if ($this->isCallable()->yes() && $otherType->isCallable()->yes()) {
+			return TrinaryLogic::createYes();
+		}
+
 		if ($otherType instanceof self) {
 			$limit = TrinaryLogic::createYes();
 		} else {

diff --git a/src/Type/CallableType.php b/src/Type/CallableType.php
@@ -83,6 +83,10 @@ public function accepts(Type $type, bool $strictTypes): TrinaryLogic
 
 	public function isSuperTypeOf(Type $type): TrinaryLogic
 	{
+		if ($type instanceof CompoundType && !$type instanceof self) {
+			return $type->isSubTypeOf($this);
+		}
+
 		return $this->isSuperTypeOfInternal($type, false);
 	}
 

diff --git a/src/Type/ClosureType.php b/src/Type/ClosureType.php
@@ -108,6 +108,10 @@ public function accepts(Type $type, bool $strictTypes): TrinaryLogic
 
 	public function isSuperTypeOf(Type $type): TrinaryLogic
 	{
+		if ($type instanceof CompoundType) {
+			return $type->isSubTypeOf($this);
+		}
+
 		return $this->isSuperTypeOfInternal($type, false);
 	}
 

diff --git a/src/Type/Generic/GenericObjectType.php b/src/Type/Generic/GenericObjectType.php
@@ -106,15 +106,15 @@ public function accepts(Type $type, bool $strictTypes): TrinaryLogic
 
 	public function isSuperTypeOf(Type $type): TrinaryLogic
 	{
+		if ($type instanceof CompoundType) {
+			return $type->isSubTypeOf($this);
+		}
+
 		return $this->isSuperTypeOfInternal($type, false);
 	}
 
 	private function isSuperTypeOfInternal(Type $type, bool $acceptsContext): TrinaryLogic
 	{
-		if ($type instanceof CompoundType) {
-			return $type->isSubTypeOf($this);
-		}
-
 		$nakedSuperTypeOf = parent::isSuperTypeOf($type);
 		if ($nakedSuperTypeOf->no()) {
 			return $nakedSuperTypeOf;

diff --git a/src/Type/Generic/TemplateTypeTrait.php b/src/Type/Generic/TemplateTypeTrait.php
@@ -6,6 +6,7 @@
 use PHPStan\Type\GeneralizePrecision;
 use PHPStan\Type\IntersectionType;
 use PHPStan\Type\MixedType;
+use PHPStan\Type\NeverType;
 use PHPStan\Type\SubtractableType;
 use PHPStan\Type\Type;
 use PHPStan\Type\TypeCombinator;
@@ -200,6 +201,10 @@ public function isSuperTypeOf(Type $type): TrinaryLogic
 			return $type->isSubTypeOf($this);
 		}
 
+		if ($type instanceof NeverType) {
+			return TrinaryLogic::createYes();
+		}
+
 		return $this->getBound()->isSuperTypeOf($type)
 			->and(TrinaryLogic::createMaybe());
 	}

diff --git a/src/Type/IntersectionType.php b/src/Type/IntersectionType.php
@@ -92,6 +92,10 @@ public function isSuperTypeOf(Type $otherType): TrinaryLogic
 			return TrinaryLogic::createYes();
 		}
 
+		if ($otherType instanceof NeverType) {
+			return TrinaryLogic::createYes();
+		}
+
 		$results = [];
 		foreach ($this->getTypes() as $innerType) {
 			$results[] = $innerType->isSuperTypeOf($otherType);

diff --git a/src/Type/IterableType.php b/src/Type/IterableType.php
@@ -78,6 +78,10 @@ public function accepts(Type $type, bool $strictTypes): TrinaryLogic
 
 	public function isSuperTypeOf(Type $type): TrinaryLogic
 	{
+		if ($type instanceof CompoundType) {
+			return $type->isSubTypeOf($this);
+		}
+
 		return $type->isIterable()
 			->and($this->getIterableValueType()->isSuperTypeOf($type->getIterableValueType()))
 			->and($this->getIterableKeyType()->isSuperTypeOf($type->getIterableKeyType()));

diff --git a/src/Type/Php/ArrayMergeFunctionDynamicReturnTypeExtension.php b/src/Type/Php/ArrayMergeFunctionDynamicReturnTypeExtension.php
@@ -55,7 +55,7 @@ public function getTypeFromFunctionCall(FunctionReflection $functionReflection,
 		}
 
 		$keyType = TypeCombinator::union(...$keyTypes);
-		if ($keyType instanceof NeverType && !$keyType->isExplicit()) {
+		if ($keyType instanceof NeverType) {
 			return new ConstantArrayType([], []);
 		}
 

diff --git a/src/Type/TypeCombinator.php b/src/Type/TypeCombinator.php
@@ -131,10 +131,6 @@ public static function union(Type ...$types): Type
 		$scalarTypes = [];
 		$hasGenericScalarTypes = [];
 		for ($i = 0; $i < $typesCount; $i++) {
-			if ($types[$i] instanceof NeverType) {
-				unset($types[$i]);
-				continue;
-			}
 			if ($types[$i] instanceof ConstantScalarType) {
 				$type = $types[$i];
 				$scalarTypes[get_class($type)][md5($type->describe(VerbosityLevel::cache()))] = $type;
@@ -378,17 +374,11 @@ private static function compareTypesInUnion(Type $a, Type $b): ?array
 			}
 		}
 
-		if (
-			!$b instanceof ConstantArrayType
-			&& $b->isSuperTypeOf($a)->yes()
-		) {
+		if ($b->isSuperTypeOf($a)->yes()) {
 			return [null, $b];
 		}
 
-		if (
-			!$a instanceof ConstantArrayType
-			&& $a->isSuperTypeOf($b)->yes()
-		) {
+		if ($a->isSuperTypeOf($b)->yes()) {
 			return [$a, null];
 		}
 

diff --git a/src/Type/UnionType.php b/src/Type/UnionType.php
@@ -116,6 +116,7 @@ public function isSuperTypeOf(Type $otherType): TrinaryLogic
 		if (
 			($otherType instanceof self && !$otherType instanceof TemplateUnionType)
 			|| $otherType instanceof IterableType
+			|| $otherType instanceof NeverType
 		) {
 			return $otherType->isSubTypeOf($this);
 		}

diff --git a/tests/PHPStan/Analyser/NodeScopeResolverTest.php b/tests/PHPStan/Analyser/NodeScopeResolverTest.php
@@ -806,6 +806,10 @@ public function dataFileAsserts(): iterable
 			yield from $this->gatherAssertTypes(__DIR__ . '/data/curl_getinfo_7.3.php');
 		}
 
+		if (PHP_VERSION_ID >= 80000) {
+			yield from $this->gatherAssertTypes(__DIR__ . '/data/bug-6251.php');
+		}
+
 		yield from $this->gatherAssertTypes(__DIR__ . '/data/bug-6584.php');
 		yield from $this->gatherAssertTypes(__DIR__ . '/data/bug-6439.php');
 		yield from $this->gatherAssertTypes(__DIR__ . '/data/bug-6748.php');

diff --git a/tests/PHPStan/Analyser/data/bug-6251.php b/tests/PHPStan/Analyser/data/bug-6251.php
@@ -0,0 +1,63 @@
+<?php declare(strict_types = 1); // lint >= 8.0
+
+namespace Bug6251;
+
+use function PHPStan\Testing\assertType;
+
+class Foo
+{
+	function foo()
+	{
+		$var = 1;
+		if (rand(0, 1)) {
+			match(1) {
+				1 =>  throw new \Exception(),
+			};
+		} else {
+			$var = 2;
+		}
+		assertType('2', $var);
+	}
+
+	function bar($a): void
+	{
+		$var = 1;
+		if (rand(0, 1)) {
+			match($a) {
+				'a' => throw new \Error(),
+				default => throw new \Exception(),
+			};
+		} else {
+			$var = 2;
+		}
+		assertType('2', $var);
+	}
+
+	function baz($a): void
+	{
+		$var = 1;
+		if (rand(0, 1)) {
+			match($a) {
+				'a' => throw new \Error(),
+				// throws UnhandledMatchError if not handled
+			};
+		} else {
+			$var = 2;
+		}
+		assertType('2', $var);
+	}
+
+	function buz($a): void
+	{
+		$var = 1;
+		if (rand(0, 1)) {
+			match($a) {
+				'a' => throw new \Exception(),
+				default => var_dump($a),
+			};
+		} else {
+			$var = 2;
+		}
+		assertType('1|2', $var);
+	}
+}
diff --git a/tests/PHPStan/Rules/Comparison/MatchExpressionRuleTest.php b/tests/PHPStan/Rules/Comparison/MatchExpressionRuleTest.php
@@ -72,17 +72,17 @@ public function testRule(): void
 				'Match expression does not handle remaining value: 3',
 				50,
 			],
-			[
-				'Match expression does not handle remaining values: 1|2|3',
-				55,
-			],
 			[
 				'Match arm comparison between 1|2 and 3 is always false.',
-				65,
+				61,
 			],
 			[
 				'Match arm comparison between 1 and 1 is always true.',
-				70,
+				66,
+			],
+			[
+				'Match expression does not handle remaining values: 1|2|3',
+				78,
 			],
 			[
 				'Match arm comparison between true and false is always false.',

diff --git a/tests/PHPStan/Rules/Comparison/data/match-expr.php b/tests/PHPStan/Rules/Comparison/data/match-expr.php
@@ -52,10 +52,6 @@ public function doFoo(int $i): void
 			// unhandled
 		};
 
-		match ($i) {
-			// unhandled
-		};
-
 		match ($i) {
 			1, 2 => null,
 			default => null, // OK
@@ -78,6 +74,10 @@ public function doFoo(int $i): void
 			default => 1,
 			1 => 2,
 		};
+
+		match ($i) {
+			// unhandled
+		};
 	}
 
 	public function doBar(\Exception $e): void

diff --git a/tests/PHPStan/Rules/Missing/MissingReturnRuleTest.php b/tests/PHPStan/Rules/Missing/MissingReturnRuleTest.php
@@ -279,4 +279,19 @@ public function testModelMixin(bool $checkExplicitMixedMissingReturn): void
 		]);
 	}
 
+	public function testBug6257(): void
+	{
+		if (PHP_VERSION_ID < 80000) {
+			$this->markTestSkipped('Test requires PHP 8.0.');
+		}
+		$this->checkExplicitMixedMissingReturn = true;
+		$this->checkPhpDocMissingReturn = true;
+		$this->analyse([__DIR__ . '/data/bug-6257.php'], [
+			[
+				'Function ReturnTypes\sometimesThrows() should always throw an exception or terminate script execution but doesn\'t do that.',
+				27,
+			],
+		]);
+	}
+
 }
diff --git a/tests/PHPStan/Rules/Missing/data/bug-6257.php b/tests/PHPStan/Rules/Missing/data/bug-6257.php
@@ -0,0 +1,31 @@
+<?php // lint >= 8.0
+
+namespace ReturnTypes;
+
+/**
+ * @return never
+ */
+function alwaysThrow() {
+	match(true) {
+		true => throw new \Exception(),
+	};
+}
+
+/**
+ * @return never
+ */
+function alwaysThrow2() {
+	match(rand(0, 1)) {
+		0 => throw new \Exception(),
+	};
+}
+
+/**
+ * @return never
+ */
+function sometimesThrows() {
+	match(rand(0, 1)) {
+		0 => throw new \Exception(),
+		default => 'test',
+	};
+}