fix(scope-manager): fix incorrect handling of class decorators and class method default params

packages/eslint-plugin/tests/eslint-rules/no-undef.test.ts

@@ -224,6 +224,17 @@ function Foo() {}
     `
 const x = 1 as const;
     `,
+    // https://github.com/typescript-eslint/typescript-eslint/issues/2942
+    `
+declare function deco(...param: any): (...param: any) => any;
+
+@deco({
+  components: {
+    val: true,
+  },
+})
+class Foo {}
+    `,
   ],
   invalid: [
     {

packages/eslint-plugin/tests/rules/no-use-before-define.test.ts

@@ -428,6 +428,20 @@ export class CidrIpPatternDirective implements Validator {}
         },
       ],
     },
+    // https://github.com/typescript-eslint/typescript-eslint/issues/2941
+    `
+class A {
+  constructor(printName) {
+    this.printName = printName;
+  }
+
+  openPort(printerName = this.printerName) {
+    this.tscOcx.ActiveXopenport(printerName);
+
+    return this;
+  }
+}
+    `,
   ],
   invalid: [
     {

packages/scope-manager/src/referencer/ClassVisitor.ts

@@ -33,6 +33,15 @@ class ClassVisitor extends Visitor {
     classVisitor.visitClass(node);
   }
 
+  visit(node: TSESTree.Node | null | undefined): void {
+    // make sure we only handle the nodes we are designed to handle
+    if (node && node.type in this) {
+      super.visit(node);
+    } else {
+      this.#referencer.visit(node);
+    }
+  }
+
   ///////////////////
   // Visit helpers //
   ///////////////////
@@ -46,7 +55,7 @@ class ClassVisitor extends Visitor {
         .defineIdentifier(node.id, new ClassNameDefinition(node.id, node));
     }
 
-    node.decorators?.forEach(d => this.visit(d));
+    node.decorators?.forEach(d => this.#referencer.visit(d));
 
     this.#referencer.scopeManager.nestClassScope(node);
 
@@ -298,6 +307,12 @@ class ClassVisitor extends Visitor {
   // Visit selectors //
   /////////////////////
 
+  protected ClassBody(node: TSESTree.ClassBody): void {
+    // this is here on purpose so that this visitor explicitly declares visitors
+    // for all nodes it cares about (see the instance visit method above)
+    this.visitChildren(node);
+  }
+
   protected ClassProperty(node: TSESTree.ClassProperty): void {
     this.visitClassProperty(node);
   }

packages/scope-manager/tests/fixtures/class/declaration/method-param-default.ts

@@ -0,0 +1,13 @@
+// https://github.com/typescript-eslint/typescript-eslint/issues/2941
+
+class A {
+  constructor(printName) {
+    this.printName = printName;
+  }
+
+  openPort(printerName = this.printerName) {
+    this.tscOcx.ActiveXopenport(printerName);
+
+    return this;
+  }
+}

packages/scope-manager/tests/fixtures/class/declaration/method-param-default.ts.shot

@@ -0,0 +1,164 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`class declaration method-param-default 1`] = `
+ScopeManager {
+  variables: Array [
+    ImplicitGlobalConstTypeVariable,
+    Variable$2 {
+      defs: Array [
+        ClassNameDefinition$1 {
+          name: Identifier<"A">,
+          node: ClassDeclaration$1,
+        },
+      ],
+      name: "A",
+      references: Array [],
+      isValueVariable: true,
+      isTypeVariable: true,
+    },
+    Variable$3 {
+      defs: Array [
+        ClassNameDefinition$2 {
+          name: Identifier<"A">,
+          node: ClassDeclaration$1,
+        },
+      ],
+      name: "A",
+      references: Array [],
+      isValueVariable: true,
+      isTypeVariable: true,
+    },
+    Variable$4 {
+      defs: Array [],
+      name: "arguments",
+      references: Array [],
+      isValueVariable: true,
+      isTypeVariable: true,
+    },
+    Variable$5 {
+      defs: Array [
+        ParameterDefinition$3 {
+          name: Identifier<"printName">,
+          node: FunctionExpression$2,
+        },
+      ],
+      name: "printName",
+      references: Array [
+        Reference$1 {
+          identifier: Identifier<"printName">,
+          isRead: true,
+          isTypeReference: false,
+          isValueReference: true,
+          isWrite: false,
+          resolved: Variable$5,
+        },
+      ],
+      isValueVariable: true,
+      isTypeVariable: false,
+    },
+    Variable$6 {
+      defs: Array [],
+      name: "arguments",
+      references: Array [],
+      isValueVariable: true,
+      isTypeVariable: true,
+    },
+    Variable$7 {
+      defs: Array [
+        ParameterDefinition$4 {
+          name: Identifier<"printerName">,
+          node: FunctionExpression$3,
+        },
+      ],
+      name: "printerName",
+      references: Array [
+        Reference$2 {
+          identifier: Identifier<"printerName">,
+          init: true,
+          isRead: false,
+          isTypeReference: false,
+          isValueReference: true,
+          isWrite: true,
+          resolved: Variable$7,
+          writeExpr: MemberExpression$4,
+        },
+        Reference$3 {
+          identifier: Identifier<"printerName">,
+          isRead: true,
+          isTypeReference: false,
+          isValueReference: true,
+          isWrite: false,
+          resolved: Variable$7,
+        },
+      ],
+      isValueVariable: true,
+      isTypeVariable: false,
+    },
+  ],
+  scopes: Array [
+    GlobalScope$1 {
+      block: Program$5,
+      isStrict: false,
+      references: Array [],
+      set: Map {
+        "const" => ImplicitGlobalConstTypeVariable,
+        "A" => Variable$2,
+      },
+      type: "global",
+      upper: null,
+      variables: Array [
+        ImplicitGlobalConstTypeVariable,
+        Variable$2,
+      ],
+    },
+    ClassScope$2 {
+      block: ClassDeclaration$1,
+      isStrict: true,
+      references: Array [],
+      set: Map {
+        "A" => Variable$3,
+      },
+      type: "class",
+      upper: GlobalScope$1,
+      variables: Array [
+        Variable$3,
+      ],
+    },
+    FunctionScope$3 {
+      block: FunctionExpression$2,
+      isStrict: true,
+      references: Array [
+        Reference$1,
+      ],
+      set: Map {
+        "arguments" => Variable$4,
+        "printName" => Variable$5,
+      },
+      type: "function",
+      upper: ClassScope$2,
+      variables: Array [
+        Variable$4,
+        Variable$5,
+      ],
+    },
+    FunctionScope$4 {
+      block: FunctionExpression$3,
+      isStrict: true,
+      references: Array [
+        Reference$2,
+        Reference$3,
+      ],
+      set: Map {
+        "arguments" => Variable$6,
+        "printerName" => Variable$7,
+      },
+      type: "function",
+      upper: ClassScope$2,
+      variables: Array [
+        Variable$6,
+        Variable$7,
+      ],
+    },
+  ],
+}
+`;

packages/scope-manager/tests/fixtures/decorators/class-deco-with-object-param.ts

@@ -0,0 +1,10 @@
+// https://github.com/typescript-eslint/typescript-eslint/issues/2942
+
+declare function deco(...param: any): (...param: any) => any;
+
+@deco({
+  components: {
+    val: true,
+  },
+})
+class Foo {}