Fluent interfaces support (#421)

fixtures/completion/this_return_value.php

@@ -0,0 +1,23 @@
+<?php
+class Grand
+{
+    /** @return $this */
+    public function foo()
+    {
+        return $this;
+    }
+}
+class Parent1 extends Grand
+{
+}
+
+class Child extends Parent1
+{
+    public function bar()
+    {
+        $this->foo()->q
+    }
+    public function qux()
+    {
+    }
+}

src/CompletionProvider.php

@@ -14,6 +14,7 @@ use LanguageServer\Protocol\{
 };
 use Microsoft\PhpParser;
 use Microsoft\PhpParser\Node;
+use Generator;
 
 class CompletionProvider
 {
@@ -196,18 +197,15 @@ class CompletionProvider
             //    $a->|
 
             // Multiple prefixes for all possible types
-            $prefixes = FqnUtilities\getFqnsFromType(
+            $fqns = FqnUtilities\getFqnsFromType(
                 $this->definitionResolver->resolveExpressionNodeToType($node->dereferencableExpression)
             );
 
-            // Include parent classes
+            // Add the object access operator to only get members of all parents
-            $prefixes = $this->expandParentFqns($prefixes);
+            $prefixes = [];
-
+            foreach ($this->expandParentFqns($fqns) as $prefix) {
-            // Add the object access operator to only get members
+                $prefixes[] = $prefix . '->';
-            foreach ($prefixes as &$prefix) {
-                $prefix .= '->';
             }
-            unset($prefix);
 
             // Collect all definitions that match any of the prefixes
             foreach ($this->index->getDefinitions() as $fqn => $def) {
@@ -232,18 +230,15 @@ class CompletionProvider
             //     TODO: $a::|
 
             // Resolve all possible types to FQNs
-            $prefixes = FqnUtilities\getFqnsFromType(
+            $fqns = FqnUtilities\getFqnsFromType(
                 $classType = $this->definitionResolver->resolveExpressionNodeToType($scoped->scopeResolutionQualifier)
             );
 
-            // Add parent classes
+            // Append :: operator to only get static members of all parents
-            $prefixes = $this->expandParentFqns($prefixes);
+            $prefixes = [];
-
+            foreach ($this->expandParentFqns($fqns) as $prefix) {
-            // Append :: operator to only get static members
+                $prefixes[] = $prefix . '::';
-            foreach ($prefixes as &$prefix) {
-                $prefix .= '::';
             }
-            unset($prefix);
 
             // Collect all definitions that match any of the prefixes
             foreach ($this->index->getDefinitions() as $fqn => $def) {
@@ -377,23 +372,22 @@ class CompletionProvider
     }
 
     /**
-     * Adds the FQNs of all parent classes to an array of FQNs of classes
+     * Yields FQNs from an array along with the FQNs of all parent classes
      *
      * @param string[] $fqns
-     * @return string[]
+     * @return Generator
      */
-    private function expandParentFqns(array $fqns): array
+    private function expandParentFqns(array $fqns) : Generator
     {
-        $expanded = $fqns;
         foreach ($fqns as $fqn) {
+            yield $fqn;
             $def = $this->index->getDefinition($fqn);
-            if ($def) {
+            if ($def !== null) {
-                foreach ($this->expandParentFqns($def->extends ?? []) as $parent) {
+                foreach ($def->getAncestorDefinitions($this->index) as $name => $def) {
-                    $expanded[] = $parent;
+                    yield $name;
                 }
             }
         }
-        return $expanded;
     }
 
     /**

src/Definition.php

@@ -3,9 +3,11 @@ declare(strict_types = 1);
 
 namespace LanguageServer;
 
+use LanguageServer\Index\ReadableIndex;
 use phpDocumentor\Reflection\{Types, Type, Fqsen, TypeResolver};
 use LanguageServer\Protocol\SymbolInformation;
 use Exception;
+use Generator;
 
 /**
  * Class used to represent symbols
@@ -95,4 +97,33 @@ class Definition
      * @var string
      */
     public $documentation;
+
+    /**
+     * Yields the definitons of all ancestor classes (the Definition fqn is yielded as key)
+     *
+     * @param ReadableIndex $index the index to search for needed definitions
+     * @param bool $includeSelf should the first yielded value be the current definition itself
+     * @return Generator
+     */
+    public function getAncestorDefinitions(ReadableIndex $index, bool $includeSelf = false): Generator
+    {
+        if ($includeSelf) {
+            yield $this->fqn => $this;
+        }
+        if ($this->extends !== null) {
+            // iterating once, storing the references and iterating again
+            // guarantees that closest definitions are yielded first
+            $definitions = [];
+            foreach ($this->extends as $fqn) {
+                $def = $index->getDefinition($fqn);
+                if ($def !== null) {
+                    yield $def->fqn => $def;
+                    $definitions[] = $def;
+                }
+            }
+            foreach ($definitions as $def) {
+                yield from $def->getAncestorDefinitions($index);
+            }
+        }
+    }
 }

src/DefinitionResolver.php

@@ -574,7 +574,6 @@ class DefinitionResolver
         //   $this -> Type\this
         //   $myVariable -> type of corresponding assignment expression
         if ($expr instanceof Node\Expression\Variable || $expr instanceof Node\UseVariableName) {
-            // TODO: this will need to change when fluent interfaces are supported
             if ($expr->getName() === 'this') {
                 return new Types\Object_(new Fqsen('\\' . $this->getContainingClassFqn($expr)));
             }
@@ -667,16 +666,24 @@ class DefinitionResolver
                 } else {
                     $classFqn = substr((string)$t->getFqsen(), 1);
                 }
-                $fqn = $classFqn . '->' . $expr->memberName->getText($expr->getFileContents());
+                $add = '->' . $expr->memberName->getText($expr->getFileContents());
                 if ($expr->parent instanceof Node\Expression\CallExpression) {
-                    $fqn .= '()';
+                    $add .= '()';
                 }
-                $def = $this->index->getDefinition($fqn);
+                $classDef = $this->index->getDefinition($classFqn);
+                if ($classDef !== null) {
+                    foreach ($classDef->getAncestorDefinitions($this->index, true) as $fqn => $def) {
+                        $def = $this->index->getDefinition($fqn . $add);
                         if ($def !== null) {
+                            if ($def->type instanceof Types\This) {
+                                return new Types\Object_(new Fqsen('\\' . $classFqn));
+                            }
                             return $def->type;
                         }
                     }
                 }
+            }
+        }
 
         // SCOPED PROPERTY ACCESS EXPRESSION
         if ($expr instanceof Node\Expression\ScopedPropertyAccessExpression) {

tests/Server/TextDocument/CompletionTest.php

@@ -653,4 +653,31 @@ class CompletionTest extends TestCase
             )
         ], true), $items);
     }
+
+    public function testThisReturnValue()
+    {
+        $completionUri = pathToUri(__DIR__ . '/../../../fixtures/completion/this_return_value.php');
+        $this->loader->open($completionUri, file_get_contents($completionUri));
+        $items = $this->textDocument->completion(
+            new TextDocumentIdentifier($completionUri),
+            new Position(17, 23)
+        )->wait();
+        $this->assertEquals(new CompletionList([
+            new CompletionItem(
+                'foo',
+                CompletionItemKind::METHOD,
+                '$this' // Return type of the method
+            ),
+            new CompletionItem(
+                'bar',
+                CompletionItemKind::METHOD,
+                'mixed' // Return type of the method
+            ),
+            new CompletionItem(
+                'qux',
+                CompletionItemKind::METHOD,
+                'mixed' // Return type of the method
+            )
+        ], true), $items);
+    }
 }