error on initialized non-nullable properties

Author: staabm

src/Analyser/MutatingScope.php

@@ -329,7 +329,7 @@ private function rememberConstructorExpressions(array $currentExpressionTypes):
 				if ($nativePropertyReflection === null || !$nativePropertyReflection->isReadOnly()) {
 						continue;
 				}
-			} elseif (!$expr instanceof ConstFetch) {
+			} elseif (!$expr instanceof ConstFetch && !$expr instanceof PropertyInitializationExpr) {
 				continue;
 			}
 

src/Rules/IssetCheck.php

@@ -5,10 +5,12 @@
 use PhpParser\Node;
 use PhpParser\Node\Expr;
 use PHPStan\Analyser\Scope;
+use PHPStan\Node\Expr\PropertyInitializationExpr;
 use PHPStan\Rules\Properties\PropertyDescriptor;
 use PHPStan\Rules\Properties\PropertyReflectionFinder;
 use PHPStan\Type\NeverType;
 use PHPStan\Type\Type;
+use PHPStan\Type\TypeCombinator;
 use PHPStan\Type\VerbosityLevel;
 use function is_string;
 use function sprintf;
@@ -143,6 +145,23 @@ public function check(Expr $expr, Scope $scope, string $operatorDescription, str
 			}
 
 			if ($propertyReflection->hasNativeType() && !$propertyReflection->isVirtual()->yes()) {
+				if (
+					$expr instanceof Node\Expr\PropertyFetch
+					&& $expr->name instanceof Node\Identifier
+					&& $expr->var instanceof Expr\Variable
+					&& $expr->var->name === 'this'
+					&& !TypeCombinator::containsNull($propertyReflection->getNativeType())
+					&& $scope->hasExpressionType(new PropertyInitializationExpr($propertyReflection->getName()))->yes()
+				) {
+					return RuleErrorBuilder::message(
+						sprintf(
+							'%s cannot be null or uninitialized %s.',
+							$this->propertyDescriptor->describeProperty($propertyReflection, $scope, $expr),
+							$operatorDescription,
+						),
+					)->identifier(sprintf('%s.neverNullOrUninitialized', $identifier))->build();
+				}
+
 				if (!$scope->hasExpressionType($expr)->yes()) {
 					if ($expr instanceof Node\Expr\PropertyFetch) {
 						return $this->checkUndefined($expr->var, $scope, $operatorDescription, $identifier);

tests/PHPStan/Rules/Variables/IssetRuleTest.php

@@ -32,6 +32,11 @@ protected function shouldTreatPhpDocTypesAsCertain(): bool
 		return $this->treatPhpDocTypesAsCertain;
 	}
 
+	public function shouldNarrowMethodScopeFromConstructor(): bool
+	{
+		return true;
+	}
+
 	public function testRule(): void
 	{
 		$this->treatPhpDocTypesAsCertain = true;
@@ -480,4 +485,16 @@ public function testBug12771(): void
 		$this->analyse([__DIR__ . '/data/bug-12771.php'], []);
 	}
 
+	public function testIssetAfterRememberedConstructor(): void
+	{
+		$this->treatPhpDocTypesAsCertain = true;
+
+		$this->analyse([__DIR__ . '/data/isset-after-remembered-constructor.php'], [
+			[
+				'Property IssetOrCoalesceOnNonNullableInitializedProperty\User::$string cannot be null or uninitialized in isset().',
+				36,
+			],
+		]);
+	}
+
 }

tests/PHPStan/Rules/Variables/NullCoalesceRuleTest.php

@@ -32,6 +32,11 @@ protected function shouldTreatPhpDocTypesAsCertain(): bool
 		return $this->treatPhpDocTypesAsCertain;
 	}
 
+	public function shouldNarrowMethodScopeFromConstructor(): bool
+	{
+		return true;
+	}
+
 	public function testCoalesceRule(): void
 	{
 		$this->treatPhpDocTypesAsCertain = true;
@@ -356,4 +361,16 @@ public function testBug12553(): void
 		$this->analyse([__DIR__ . '/data/bug-12553.php'], []);
 	}
 
+	public function testIssetAfterRememberedConstructor(): void
+	{
+		$this->treatPhpDocTypesAsCertain = true;
+
+		$this->analyse([__DIR__ . '/data/isset-after-remembered-constructor.php'], [
+			[
+				'Property IssetOrCoalesceOnNonNullableInitializedProperty\User::$string cannot be null or uninitialized on left side of ??.',
+				48,
+			],
+		]);
+	}
+
 }

tests/PHPStan/Rules/Variables/data/isset-after-remembered-constructor.php

@@ -0,0 +1,51 @@
+<?php // lint >= 7.4
+
+namespace IssetOrCoalesceOnNonNullableInitializedProperty;
+
+use function PHPStan\debugScope;
+
+class User
+{
+    private ?string $nullableString;
+    private string $maybeUninitializedString;
+    private string $string;
+
+    private $untyped;
+
+    public function __construct(
+    ) {
+        if (rand(0,1)) {
+            $this->nullableString = 'hello';
+            $this->string = 'world';
+            $this->maybeUninitializedString = 'something';
+        } else {
+            $this->nullableString = null;
+            $this->string = 'world 2';
+            $this->untyped = 123;
+        }
+    }
+
+    public function doFoo(): void
+    {
+        if (isset($this->maybeUninitializedString)) {
+            echo $this->maybeUninitializedString;
+        }
+        if (isset($this->nullableString)) {
+            echo $this->nullableString;
+        }
+        if (isset($this->string)) {
+            echo $this->string;
+        }
+        if (isset($this->untyped)) {
+            echo $this->untyped;
+        }
+    }
+
+    public function doBar(): void
+    {
+        echo $this->maybeUninitializedString ?? 'default';
+        echo $this->nullableString ?? 'default';
+        echo $this->string ?? 'default';
+        echo $this->untyped ?? 'default';
+    }
+}