Fix #4912 - detect mismatching property type

config.xsd

@@ -275,6 +275,7 @@
             <xs:element name="MethodSignatureMismatch" type="IssueHandlerType" minOccurs="0" />
             <xs:element name="MethodSignatureMustOmitReturnType" type="IssueHandlerType" minOccurs="0" />
             <xs:element name="MismatchingDocblockParamType" type="IssueHandlerType" minOccurs="0" />
+            <xs:element name="MismatchingDocblockPropertyType" type="IssueHandlerType" minOccurs="0" />
             <xs:element name="MismatchingDocblockReturnType" type="IssueHandlerType" minOccurs="0" />
             <xs:element name="MissingClosureParamType" type="IssueHandlerType" minOccurs="0" />
             <xs:element name="MissingClosureReturnType" type="IssueHandlerType" minOccurs="0" />

docs/running_psalm/issues/MismatchingDocblockPropertyType.md

@@ -0,0 +1,11 @@
+# MismatchingDocblockPropertyType
+
+Emitted when an `@var` entry in a property’s docblock does not match the property's type.
+
+```php
+<?php
+class A {
+    /** @var array */
+    public string $s = [];
+}
+```

src/Psalm/Internal/Analyzer/ClassAnalyzer.php

@@ -23,6 +23,7 @@ use Psalm\Issue\InternalClass;
 use Psalm\Issue\InvalidExtendClass;
 use Psalm\Issue\InvalidTemplateParam;
 use Psalm\Issue\MethodSignatureMismatch;
+use Psalm\Issue\MismatchingDocblockPropertyType;
 use Psalm\Issue\MissingConstructor;
 use Psalm\Issue\MissingImmutableAnnotation;
 use Psalm\Issue\MissingPropertyType;
@@ -1137,6 +1138,32 @@ class ClassAnalyzer extends ClassLikeAnalyzer
                     [],
                     false
                 );
+
+                if ($property_storage->signature_type) {
+                    $union_comparison_result = new \Psalm\Internal\Type\Comparator\TypeComparisonResult();
+
+                    if (!UnionTypeComparator::isContainedBy(
+                        $codebase,
+                        $fleshed_out_type,
+                        $property_storage->signature_type,
+                        false,
+                        false,
+                        $union_comparison_result
+                    ) && !$union_comparison_result->type_coerced_from_mixed
+                    ) {
+                        if (IssueBuffer::accepts(
+                            new MismatchingDocblockPropertyType(
+                                'Parameter '
+                                    . $property_class_name . '::$' . $property_name
+                                    . ' has wrong type \'' . $fleshed_out_type .
+                                    '\', should be \'' . $property_storage->signature_type . '\'',
+                                $property_type_location
+                            )
+                        )) {
+                            // do nothing
+                        }
+                    }
+                }
             }
 
             if ($property_storage->is_static) {

src/Psalm/Issue/MismatchingDocblockPropertyType.php

@@ -0,0 +1,8 @@
+<?php
+namespace Psalm\Issue;
+
+class MismatchingDocblockPropertyType extends CodeIssue
+{
+    public const ERROR_LEVEL = 2;
+    public const SHORTCODE = 264;
+}

tests/PropertyTypeTest.php

@@ -3534,6 +3534,14 @@ class PropertyTypeTest extends TestCase
                     echo (new A)->foo;',
                 'error_message' => 'InaccessibleProperty',
             ],
+            'overwritePropertyType' => [
+                '<?php
+                    class A {
+                        /** @var array */
+                        public string $s = [];
+                    }',
+                'error_message' => 'MismatchingDocblockPropertyType',
+            ],
         ];
     }
 }