refactor(scope): remove special-case handling of $this

src/CompletionProvider.php

@@ -201,9 +201,6 @@ class CompletionProvider
             $prefixLen = strlen($namePrefix);
             $scope = getScopeAtNode($this->definitionResolver, $node);
             $variables = $scope->variables;
-            if ($scope->thisVariable !== null) {
-                $variables['this'] = $scope->thisVariable;
-            }
             foreach ($variables as $name => $var) {
                 if (substr($name, 0, $prefixLen) !== $namePrefix) {
                     continue;

src/DefinitionResolver.php

@@ -563,9 +563,6 @@ class DefinitionResolver
         //   $myVariable -> type of corresponding assignment expression
         if ($expr instanceof Node\Expression\Variable || $expr instanceof Node\UseVariableName) {
             $name = $expr->getName();
-            if ($name === 'this') {
-                return $scope->thisVariable === null ? new Types\Mixed_ : $scope->thisVariable->type;
-            }
             return isset($scope->variables[$name])
                 ? $scope->variables[$name]->type
                 : new Types\Mixed_;

src/Scope/Scope.php

@@ -9,13 +9,6 @@ use Microsoft\PhpParser\Node\QualifiedName;
  */
 class Scope
 {
-    /**
-     * @var Variable|null $this
-     *
-     * Note that this will be set when a class is entered. It is unset again when entering a static function.
-     */
-    public $thisVariable;
-
     /**
      * @var Variable|null $this, except also set in static contexts.
      */

src/Scope/TreeTraverser.php

@@ -102,8 +102,8 @@ class TreeTraverser
             $childScope->currentClassLikeVariable = $scope->currentClassLikeVariable;
             $childScope->resolvedNameCache = $scope->resolvedNameCache;
             $isStatic = $node instanceof Node\MethodDeclaration ? $node->isStatic() : !empty($node->staticModifier);
-            if (!$isStatic) {
+            if (!$isStatic && isset($scope->variables['this'])) {
-                $childScope->thisVariable = $scope->thisVariable;
+                $childScope->variables['this'] = $scope->variables['this'];
             }
 
             if ($node->parameters !== null) {
@@ -138,11 +138,12 @@ class TreeTraverser
         ) {
             $childScope = new Scope;
             $childScope->resolvedNameCache = $scope->resolvedNameCache;
-            $childScope->thisVariable = new Variable(
+            $thisVar = new Variable(
                 new Types\Object_(new Fqsen('\\' . (string)$node->getNamespacedName())),
                 $node
             );
-            $childScope->currentClassLikeVariable = $childScope->thisVariable;
+            $childScope->variables['this'] = $thisVar;
+            $childScope->currentClassLikeVariable = $thisVar;
             return $childScope;
         }
 

src/TreeAnalyzer.php

@@ -106,8 +106,8 @@ class TreeAnalyzer
         }
 
         // Check for invalid usage of $this.
-        if ($scope->thisVariable === null &&
+        if ($node instanceof Node\Expression\Variable &&
-            $node instanceof Node\Expression\Variable &&
+            !isset($scope->variables['this']) &&
             $node->getName() === 'this'
         ) {
             $this->diagnostics[] = new Diagnostic(