Properly filter completion on empty property

fixtures/completion/property.php

@@ -1,4 +1,4 @@
 <?php
 
 $obj = new TestClass;
-$obj->t
+$obj->

src/CompletionProvider.php

@@ -56,14 +56,38 @@ class CompletionProvider
             || $node instanceof Node\Expr\StaticPropertyFetch
             || $node instanceof Node\Expr\ClassConstFetch
         ) {
-            /** The FQN to be completed */
-            $prefix = $this->definitionResolver->resolveReferenceNodeToFqn($node) ?? '';
-            $prefixLen = strlen($prefix);
+            $nodeToResolve = $node;
+            if (!is_string($node->name)) {
+                // If the name is an Error node, just filter by the class
+                if ($node instanceof Node\Expr\MethodCall || $node instanceof Node\Expr\PropertyFetch) {
+                    $nodeToResolve = $node->var;
+                } else {
+                    $nodeToResolve = $node->class;
+                }
+            }
+            $prefixes = DefinitionResolver::getFqnsFromType(
+                $this->definitionResolver->resolveExpressionNodeToType($nodeToResolve)
+            );
+            if (!is_string($node->name)) {
+                // If we are just filtering by the class, add the appropiate operator to the prefix
+                // to filter the type of symbol
+                foreach ($prefixes as &$prefix) {
+                    if ($node instanceof Node\Expr\MethodCall || $node instanceof Node\Expr\PropertyFetch) {
+                        $prefix .= '->';
+                    } else if ($node instanceof Node\Expr\StaticCall || $node instanceof Node\Expr\ClassConstFetch) {
+                        $prefix .= '::';
+                    } else if ($node instanceof Node\Expr\StaticPropertyFetch) {
+                        $prefix .= '::$';
+                    }
+                }
+            }
             foreach ($this->project->getDefinitions() as $fqn => $def) {
-                if (substr($fqn, 0, $prefixLen) === $prefix && !$def->isGlobal) {
+                foreach ($prefixes as $prefix) {
+                    if (substr($fqn, 0, strlen($prefix)) === $prefix && !$def->isGlobal) {
                         $items[] = CompletionItem::fromDefinition($def);
                     }
                 }
+            }
         } else if (
             // A ConstFetch means any static reference, like a class, interface, etc.
             ($node instanceof Node\Name && $node->getAttribute('parentNode') instanceof Node\Expr\ConstFetch)

src/DefinitionResolver.php

@@ -146,6 +146,31 @@ class DefinitionResolver
         return $this->project->getDefinition($fqn, $globalFallback);
     }
 
+    /**
+     * Returns all possible FQNs in a type
+     *
+     * @param Type $type
+     * @return string[]
+     */
+    public static function getFqnsFromType(Type $type): array
+    {
+        $fqns = [];
+        if ($type instanceof Types\Object_) {
+            $fqsen = $type->getFqsen();
+            if ($fqsen !== null) {
+                $fqns[] = substr((string)$fqsen, 1);
+            }
+        }
+        if ($type instanceof Types\Compound) {
+            for ($i = 0; $t = $type->get($i); $i++) {
+                foreach (self::getFqnsFromType($type) as $fqn) {
+                    $fqns[] = $fqn;
+                }
+            }
+        }
+        return $fqns;
+    }
+
     /**
      * Given any node, returns the FQN of the symbol that is referenced
      * Returns null if the FQN could not be resolved or the reference node references a variable

tests/Server/TextDocument/CompletionTest.php

@@ -30,13 +30,37 @@ class CompletionTest extends TestCase
         $this->textDocument = new Server\TextDocument($this->project, $client);
     }
 
-    public function testForPropertiesAndMethods()
+    public function testPropertyAndMethodWithPrefix()
+    {
+        $completionUri = pathToUri(__DIR__ . '/../../../fixtures/completion/property_with_prefix.php');
+        $this->project->openDocument($completionUri, file_get_contents($completionUri));
+        $items = $this->textDocument->completion(
+            new TextDocumentIdentifier($completionUri),
+            new Position(3, 7)
+        )->wait();
+        $this->assertEquals([
+            new CompletionItem(
+                'testProperty',
+                CompletionItemKind::PROPERTY,
+                '\TestClass', // Type of the property
+                'Reprehenderit magna velit mollit ipsum do.'
+            ),
+            new CompletionItem(
+                'testMethod',
+                CompletionItemKind::METHOD,
+                '\TestClass', // Return type of the method
+                'Non culpa nostrud mollit esse sunt laboris in irure ullamco cupidatat amet.'
+            )
+        ], $items);
+    }
+
+    public function testPropertyAndMethodWithoutPrefix()
     {
         $completionUri = pathToUri(__DIR__ . '/../../../fixtures/completion/property.php');
         $this->project->openDocument($completionUri, file_get_contents($completionUri));
         $items = $this->textDocument->completion(
             new TextDocumentIdentifier($completionUri),
-            new Position(3, 7)
+            new Position(3, 6)
         )->wait();
         $this->assertEquals([
             new CompletionItem(