Use Type::getFiniteTypes() for removing types

Author: ondrejmirtes

phpstan-baseline.neon

@@ -31,6 +31,11 @@ parameters:
 			count: 1
 			path: src/Analyser/MutatingScope.php
 
+		-
+			message: "#^Casting to string something that's already string\\.$#"
+			count: 2
+			path: src/Analyser/MutatingScope.php
+
 		-
 			message: "#^Doing instanceof PHPStan\\\\Type\\\\Constant\\\\ConstantBooleanType is error\\-prone and deprecated\\. Use Type\\:\\:isTrue\\(\\) or Type\\:\\:isFalse\\(\\) instead\\.$#"
 			count: 4

src/Analyser/MutatingScope.php

@@ -3659,7 +3659,7 @@ public function filterBySpecifiedTypes(SpecifiedTypes $specifiedTypes): self
 			}
 			$typeSpecifications[] = [
 				'sure' => true,
-				'exprString' => $exprString,
+				'exprString' => (string) $exprString,
 				'expr' => $expr,
 				'type' => $type,
 			];
@@ -3670,7 +3670,7 @@ public function filterBySpecifiedTypes(SpecifiedTypes $specifiedTypes): self
 			}
 			$typeSpecifications[] = [
 				'sure' => false,
-				'exprString' => $exprString,
+				'exprString' => (string) $exprString,
 				'expr' => $expr,
 				'type' => $type,
 			];

src/Analyser/TypeSpecifier.php

@@ -225,8 +225,7 @@ public function specifyTypesInCondition(
 			$exprLeftType = $scope->getType($expr->left);
 			$exprRightType = $scope->getType($expr->right);
 			if (
-				count($exprLeftType->getConstantScalarValues()) === 1
-				|| count($exprLeftType->getEnumCases()) === 1
+				count($exprLeftType->getFiniteTypes()) === 1
 				|| ($exprLeftType->isConstantValue()->yes() && !$exprRightType->equals($exprLeftType) && $exprRightType->isSuperTypeOf($exprLeftType)->yes())
 			) {
 				$types = $this->create(
@@ -239,8 +238,7 @@ public function specifyTypesInCondition(
 				);
 			}
 			if (
-				count($exprRightType->getConstantScalarValues()) === 1
-				|| count($exprRightType->getEnumCases()) === 1
+				count($exprRightType->getFiniteTypes()) === 1
 				|| ($exprRightType->isConstantValue()->yes() && !$exprLeftType->equals($exprRightType) && $exprLeftType->isSuperTypeOf($exprRightType)->yes())
 			) {
 				$leftType = $this->create(

src/Type/TypeCombinator.php

@@ -74,7 +74,41 @@ public static function remove(Type $fromType, Type $typeToRemove): Type
 			}
 		}
 
-		return $fromType->tryRemove($typeToRemove) ?? $fromType;
+		$removed = $fromType->tryRemove($typeToRemove);
+		if ($removed !== null) {
+			return $removed;
+		}
+
+		$fromFiniteTypes = $fromType->getFiniteTypes();
+		if (count($fromFiniteTypes) > 0) {
+			$finiteTypesToRemove = $typeToRemove->getFiniteTypes();
+			if (count($finiteTypesToRemove) === 1) {
+				$result = [];
+				foreach ($fromFiniteTypes as $finiteType) {
+					if ($finiteType->equals($finiteTypesToRemove[0])) {
+						continue;
+					}
+
+					$result[] = $finiteType;
+				}
+
+				if (count($result) === count($fromFiniteTypes)) {
+					return $fromType;
+				}
+
+				if (count($result) === 0) {
+					return new NeverType();
+				}
+
+				if (count($result) === 1) {
+					return $result[0];
+				}
+
+				return new UnionType($result);
+			}
+		}
+
+		return $fromType;
 	}
 
 	public static function removeNull(Type $type): Type

tests/PHPStan/Analyser/NodeScopeResolverTest.php

@@ -1261,6 +1261,7 @@ public function dataFileAsserts(): iterable
 		yield from $this->gatherAssertTypes(__DIR__ . '/data/bug-9404.php');
 		yield from $this->gatherAssertTypes(__DIR__ . '/data/globals.php');
 		yield from $this->gatherAssertTypes(__DIR__ . '/data/bug-9208.php');
+		yield from $this->gatherAssertTypes(__DIR__ . '/data/finite-types.php');
 	}
 
 	/**

tests/PHPStan/Analyser/data/finite-types.php

@@ -0,0 +1,33 @@
+<?php
+
+namespace FiniteTypes;
+
+use function PHPStan\Testing\assertType;
+
+class Foo
+{
+
+	public function doFoo(bool $a, bool $b): void
+	{
+		$array = [$a, $b];
+		if ($array === [true, false]) {
+			assertType('array{true, false}', $array);
+			return;
+		}
+
+		assertType('array{false, false}|array{false, true}|array{true, true}', $array);
+		if ($array === [false, false]) {
+			assertType('array{false, false}', $array);
+			return;
+		}
+
+		assertType('array{bool, true}', $array);
+		if ($array === [true, true]) {
+			assertType('array{true, true}', $array);
+			return;
+		}
+
+		assertType('array{false, true}', $array);
+	}
+
+}