Specify conditional types for all falsey scalars

Author: staabm

src/Analyser/NodeScopeResolver.php

@@ -173,6 +173,7 @@
 use PHPStan\Type\Constant\ConstantArrayTypeBuilder;
 use PHPStan\Type\Constant\ConstantIntegerType;
 use PHPStan\Type\Constant\ConstantStringType;
+use PHPStan\Type\ConstantTypeHelper;
 use PHPStan\Type\FileTypeMapper;
 use PHPStan\Type\GeneralizePrecision;
 use PHPStan\Type\Generic\TemplateTypeHelper;
@@ -6108,6 +6109,35 @@ private function processAssignVar(
 					$conditionalExpressions = $this->processSureNotTypesForConditionalExpressionsAfterAssign($scope, $var->name, $conditionalExpressions, $falseySpecifiedTypes, $falseyType);
 				}
 
+				foreach ([null, false, 0, 0.0, '', '0', []] as $falseyScalar) {
+					$falseyType = ConstantTypeHelper::getTypeFromValue($falseyScalar);
+					$withoutFalseyType = TypeCombinator::remove($type, $falseyType);
+					if (
+						$withoutFalseyType->equals($type)
+						|| $withoutFalseyType->equals($truthyType)
+					) {
+						continue;
+					}
+
+					$astNode = match ($falseyScalar) {
+						null => new ConstFetch(new Name('null')),
+						false =>    new ConstFetch(new Name('false')),
+						0 =>    new Node\Scalar\Int_($falseyScalar),
+						0.0 =>  new Node\Scalar\Float_($falseyScalar),
+						'', '0' => new Node\Scalar\String_($falseyScalar),
+						[] => new Node\Expr\Array_($falseyScalar),
+					};
+					$notConditionExpr = new Expr\BinaryOp\NotIdentical($assignedExpr, $astNode);
+					$notSpecifiedTypes = $this->typeSpecifier->specifyTypesInCondition($scope, $notConditionExpr, TypeSpecifierContext::createTrue());
+					$conditionalExpressions = $this->processSureTypesForConditionalExpressionsAfterAssign($scope, $var->name, $conditionalExpressions, $notSpecifiedTypes, $withoutFalseyType);
+					$conditionalExpressions = $this->processSureNotTypesForConditionalExpressionsAfterAssign($scope, $var->name, $conditionalExpressions, $notSpecifiedTypes, $withoutFalseyType);
+
+					$conditionExpr = new Expr\BinaryOp\Identical($assignedExpr, $astNode);
+					$specifiedTypes = $this->typeSpecifier->specifyTypesInCondition($scope, $conditionExpr, TypeSpecifierContext::createTrue());
+					$conditionalExpressions = $this->processSureTypesForConditionalExpressionsAfterAssign($scope, $var->name, $conditionalExpressions, $specifiedTypes, $falseyType);
+					$conditionalExpressions = $this->processSureNotTypesForConditionalExpressionsAfterAssign($scope, $var->name, $conditionalExpressions, $specifiedTypes, $falseyType);
+				}
+
 				$this->callNodeCallback($nodeCallback, new VariableAssignNode($var, $assignedExpr), $scopeBeforeAssignEval, $storage);
 				$scope = $scope->assignVariable($var->name, $type, $scope->getNativeType($assignedExpr), TrinaryLogic::createYes());
 				foreach ($conditionalExpressions as $exprString => $holders) {

tests/PHPStan/Analyser/nsrt/bug-13546.php

@@ -66,10 +66,10 @@ function mixedLast($mixed): void
 function firstInCondition(array $array)
 {
 	if (($key = array_key_first($array)) !== null) {
-		assertType('list<string>', $array); // could be 'non-empty-list<string>'
+		assertType('non-empty-list<string>', $array);
 		return $array[$key];
 	}
-	assertType('list<string>', $array);
+	assertType('array{}', $array);
 	return null;
 }
 

tests/PHPStan/Analyser/nsrt/bug-14081.php

@@ -48,7 +48,7 @@ function firstNotNull(array $array): mixed
 {
 	if (($key = array_key_first($array)) !== null) {
 		assertType('int<0, max>', $key);
-		assertType('list<string>', $array); // could be non-empty-list<string>
+		assertType('non-empty-list<string>', $array);
 		assertType('string', $array[$key]);
 		return $array[$key];
 	}
@@ -60,7 +60,7 @@ function lastNotNull(array $array): mixed
 {
 	if (($key = array_key_last($array)) !== null) {
 		assertType('int<0, max>', $key);
-		assertType('list<string>', $array); // could be non-empty-list<string>
+		assertType('non-empty-list<string>', $array);
 		assertType('string', $array[$key]);
 		return $array[$key];
 	}

tests/PHPStan/Rules/Arrays/NonexistentOffsetInArrayDimFetchRuleTest.php

@@ -840,7 +840,7 @@ public function testArrayDimFetchAfterArraySearch(): void
 
 		$this->analyse([__DIR__ . '/data/array-dim-after-array-search.php'], [
 			[
-				'Offset int|string might not exist on array.',
+				'Offset int|string might not exist on non-empty-array.',
 				20,
 			],
 		]);