fix(parser): fix crash when visiting decorators in parameters (typescript-eslint#237)

- fix visiting decorators in parameters
- fix issue with this in no-shadow

Author: armano2

Diff for: packages/eslint-plugin/src/rules/no-unused-vars.ts

@@ -24,22 +24,6 @@ export default util.createRule({
   create(context) {
     const rules = baseRule.create(context);
 
-    /**
-     * Mark this function parameter as used
-     * @param node The node currently being traversed
-     */
-    function markThisParameterAsUsed(node: TSESTree.Identifier): void {
-      if (node.name) {
-        const variable = context
-          .getScope()
-          .variables.find(scopeVar => scopeVar.name === node.name);
-
-        if (variable) {
-          variable.eslintUsed = true;
-        }
-      }
-    }
-
     /**
      * Mark heritage clause as used
      * @param node The node currently being traversed
@@ -59,8 +43,6 @@ export default util.createRule({
     }
 
     return Object.assign({}, rules, {
-      "FunctionDeclaration Identifier[name='this']": markThisParameterAsUsed,
-      "FunctionExpression Identifier[name='this']": markThisParameterAsUsed,
       'TSTypeReference Identifier'(node: TSESTree.Identifier) {
         context.markVariableAsUsed(node.name);
       },

Diff for: packages/eslint-plugin/tests/eslint-rules/no-shadow.test.ts

@@ -21,6 +21,12 @@ function bar(foo: any) {}
     `
 export abstract class Foo {}
 export class FooBar extends Foo {}
+    `,
+    // https://github.com/typescript-eslint/typescript-eslint/issues/207
+    `
+function test(this: Foo) {
+  function test2(this: Bar) {}
+}
     `
   ],
   invalid: []

Diff for: packages/eslint-plugin/tests/eslint-rules/no-unused-vars.test.ts

@@ -577,7 +577,36 @@ export function Foo() {
   );
 }
       `
-    }
+    },
+    // https://github.com/eslint/typescript-eslint-parser/issues/535
+    `
+import { observable } from 'mobx';
+export default class ListModalStore {
+  @observable
+  orderList: IObservableArray<BizPurchaseOrderTO> = observable([]);
+}
+    `,
+    // https://github.com/typescript-eslint/typescript-eslint/issues/122#issuecomment-462008078
+    `
+import { Dec, TypeA, Class } from 'test';
+export default class Foo {
+  constructor(
+    @Dec(Class)
+    private readonly prop: TypeA<Class>,
+  ) {}
+}
+    `,
+    `
+import { Dec, TypeA, Class } from 'test';
+export default class Foo {
+  constructor(
+    @Dec(Class)
+    ...prop: TypeA<Class>,
+  ) {
+    prop()
+  }
+}
+    `
   ],
 
   invalid: [

Diff for: packages/eslint-plugin/tests/rules/no-unused-vars.test.ts

@@ -11,7 +11,7 @@ import {
   PatternVisitorCallback,
   PatternVisitorOptions
 } from 'eslint-scope/lib/options';
-import { TSESTree } from '@typescript-eslint/typescript-estree';
+import { TSESTree, AST_NODE_TYPES } from '@typescript-eslint/typescript-estree';
 
 /**
  * Define the override function of `Scope#__define` for global augmentation.
@@ -90,6 +90,13 @@ class PatternVisitor extends OriginalPatternVisitor {
       this.rightHandNodes.push(node.typeAnnotation);
     }
   }
+
+  TSParameterProperty(node: TSESTree.TSParameterProperty): void {
+    this.visit(node.parameter);
+    if (node.decorators) {
+      this.rightHandNodes.push(...node.decorators);
+    }
+  }
 }
 
 class Referencer extends OriginalReferencer {
@@ -182,11 +189,16 @@ class Referencer extends OriginalReferencer {
         params[i],
         { processRightHandNodes: true },
         (pattern, info) => {
-          innerScope.__define(
-            pattern,
-            new ParameterDefinition(pattern, node, i, info.rest)
-          );
-          this.referencingDefaultValue(pattern, info.assignments, null, true);
+          if (
+            pattern.type !== AST_NODE_TYPES.Identifier ||
+            pattern.name !== 'this'
+          ) {
+            innerScope.__define(
+              pattern,
+              new ParameterDefinition(pattern, node, i, info.rest)
+            );
+            this.referencingDefaultValue(pattern, info.assignments, null, true);
+          }
         }
       );
     }

Diff for: packages/parser/src/analyze-scope.ts

@@ -4,7 +4,7 @@ export const visitorKeys = eslintVisitorKeys.unionWith({
   // Additional estree nodes.
   Import: [],
   // Additional Properties.
-  ArrayPattern: ['elements', 'typeAnnotation'],
+  ArrayPattern: ['decorators', 'elements', 'typeAnnotation'],
   ArrowFunctionExpression: ['typeParameters', 'params', 'returnType', 'body'],
   ClassDeclaration: [
     'decorators',
@@ -24,12 +24,13 @@ export const visitorKeys = eslintVisitorKeys.unionWith({
     'implements',
     'body'
   ],
+  TaggedTemplateExpression: ['tag', 'typeParameters', 'quasi'],
   FunctionDeclaration: ['id', 'typeParameters', 'params', 'returnType', 'body'],
   FunctionExpression: ['id', 'typeParameters', 'params', 'returnType', 'body'],
   Identifier: ['decorators', 'typeAnnotation'],
   MethodDefinition: ['decorators', 'key', 'value'],
-  ObjectPattern: ['properties', 'typeAnnotation'],
-  RestElement: ['argument', 'typeAnnotation'],
+  ObjectPattern: ['decorators', 'properties', 'typeAnnotation'],
+  RestElement: ['decorators', 'argument', 'typeAnnotation'],
   NewExpression: ['callee', 'typeParameters', 'arguments'],
   CallExpression: ['callee', 'typeParameters', 'arguments'],
   // JSX
@@ -56,7 +57,7 @@ export const visitorKeys = eslintVisitorKeys.unionWith({
   TSConditionalType: ['checkType', 'extendsType', 'trueType', 'falseType'],
   TSConstructSignatureDeclaration: ['typeParameters', 'params', 'returnType'],
   TSConstructorType: ['typeParameters', 'params', 'returnType'],
-  TSDeclareFunction: ['id', 'typeParameters', 'params', 'returnType'],
+  TSDeclareFunction: ['id', 'typeParameters', 'params', 'returnType', 'body'],
   TSDeclareKeyword: [],
   TSEmptyBodyFunctionExpression: [
     'id',
@@ -91,7 +92,7 @@ export const visitorKeys = eslintVisitorKeys.unionWith({
   TSNumberKeyword: [],
   TSObjectKeyword: [],
   TSOptionalType: ['typeAnnotation'],
-  TSParameterProperty: ['parameter'],
+  TSParameterProperty: ['decorators', 'parameter'],
   TSParenthesizedType: ['typeAnnotation'],
   TSPrivateKeyword: [],
   TSPropertySignature: ['typeAnnotation', 'key', 'initializer'],

Diff for: packages/parser/src/visitor-keys.ts

@@ -0,0 +1,3 @@
+export default class Foo {
+  constructor(@Dec []: string[]) {}
+}

Diff for: packages/parser/tests/fixtures/scope-analysis/decorator-parameter-property-array.ts

@@ -0,0 +1,3 @@
+export default class Foo {
+  constructor(@Dec test: string) {}
+}

Diff for: packages/parser/tests/fixtures/scope-analysis/decorator-parameter-property-identifier.ts

@@ -0,0 +1,3 @@
+export default class Foo {
+  constructor(@Dec {}: any) {}
+}

Diff for: packages/parser/tests/fixtures/scope-analysis/decorator-parameter-property-object.ts

@@ -0,0 +1,3 @@
+export default class Foo {
+  constructor(@Dec private readonly test: string) {}
+}

Diff for: packages/parser/tests/fixtures/scope-analysis/decorator-parameter-property-parameter.ts

@@ -0,0 +1,3 @@
+export default class Foo {
+  constructor(@Dec ...test: string[]) {}
+}