fix: update no-invalid-this and no-eval for class static blocks (#15300)

Fixes false positives of rules `no-invalid-this` and `no-eval` in cases where `this` is used in class static blocks.

Refs #15016

docs/rules/no-eval.md

@@ -66,6 +66,14 @@ class A {
 
     eval() {
     }
+
+    static {
+        // This is a user-defined static method.
+        this.eval("var a = 0");
+    }
+
+    static eval() {
+    }
 }
 ```
 

docs/rules/no-invalid-this.md

@@ -18,14 +18,19 @@ This rule judges from following conditions whether or not the function is a meth
 
 * The function is on an object literal.
 * The function is assigned to a property.
-* The function is a method/getter/setter of ES2015 Classes. (excepts static methods)
+* The function is a method/getter/setter of ES2015 Classes.
 
 And this rule allows `this` keywords in functions below:
 
 * The `call/apply/bind` method of the function is called directly.
 * The function is a callback of array methods (such as `.forEach()`) if `thisArg` is given.
 * The function has `@this` tag in its JSDoc comment.
 
+And this rule always allows `this` keywords in the following contexts:
+
+* In class field initializers.
+* In class static blocks.
+
 Otherwise are considered problems.
 
 This rule applies **only** in strict mode.
@@ -166,6 +171,13 @@ Foo.prototype.foo = function foo() {
 };
 
 class Foo {
+
+    // OK, this is in a class field initializer.
+    a = this.b;
+
+    // OK, static initializers also have valid this.
+    static a = this.b;
+
     foo() {
         // OK, this is in a method.
         this.a = 0;
@@ -177,6 +189,12 @@ class Foo {
         this.a = 0;
         baz(() => this);
     }
+
+    static {
+        // OK, static blocks also have valid this.
+        this.a = 0;
+        baz(() => this);
+    }
 }
 
 var foo = (function foo() {

lib/rules/no-eval.js

@@ -248,6 +248,8 @@ module.exports = {
             "ArrowFunctionExpression:exit": exitVarScope,
             "PropertyDefinition > *.value": enterVarScope,
             "PropertyDefinition > *.value:exit": exitVarScope,
+            StaticBlock: enterVarScope,
+            "StaticBlock:exit": exitVarScope,
 
             ThisExpression(node) {
                 if (!isMember(node.parent, "eval")) {

lib/rules/no-invalid-this.js

@@ -132,6 +132,10 @@ module.exports = {
             "PropertyDefinition > *.value": enterFunction,
             "PropertyDefinition > *.value:exit": exitFunction,
 
+            // Class static blocks are implicit functions.
+            StaticBlock: enterFunction,
+            "StaticBlock:exit": exitFunction,
+
             // Reports if `this` of the current context is invalid.
             ThisExpression(node) {
                 const current = stack.getCurrent();

lib/rules/utils/ast-utils.js

@@ -937,6 +937,8 @@ module.exports = {
      *
      * First, this checks the node:
      *
+     * - The given node is not in `PropertyDefinition#value` position.
+     * - The given node is not `StaticBlock`.
      * - The function name does not start with uppercase. It's a convention to capitalize the names
      *   of constructor functions. This check is not performed if `capIsConstructor` is set to `false`.
      * - The function does not have a JSDoc comment that has a @this tag.
@@ -951,7 +953,8 @@ module.exports = {
      * - The location is not on an ES2015 class.
      * - Its `bind`/`call`/`apply` method is not called directly.
      * - The function is not a callback of array methods (such as `.forEach()`) if `thisArg` is given.
-     * @param {ASTNode} node A function node to check.
+     * @param {ASTNode} node A function node to check. It also can be an implicit function, like `StaticBlock`
+     * or any expression that is `PropertyDefinition#value` node.
      * @param {SourceCode} sourceCode A SourceCode instance to get comments.
      * @param {boolean} [capIsConstructor = true] `false` disables the assumption that functions which name starts
      * with an uppercase or are assigned to a variable which name starts with an uppercase are constructors.
@@ -964,7 +967,12 @@ module.exports = {
          * Therefore, A expression node at `PropertyDefinition#value` is a function.
          * In this case, `this` is always not default binding.
          */
-        if (node && node.parent && node.parent.type === "PropertyDefinition" && node.value === node) {
+        if (node.parent.type === "PropertyDefinition" && node.parent.value === node) {
+            return false;
+        }
+
+        // Class static blocks are implicit functions. In this case, `this` is always not default binding.
+        if (node.type === "StaticBlock") {
             return false;
         }
 

tests/lib/rules/no-eval.js

@@ -50,6 +50,7 @@ ruleTester.run("no-eval", rule, {
         { code: "class A { static foo() { this.eval(); } }", parserOptions: { ecmaVersion: 6 } },
         { code: "class A { field = this.eval(); }", parserOptions: { ecmaVersion: 2022 } },
         { code: "class A { field = () => this.eval(); }", parserOptions: { ecmaVersion: 2022 } },
+        { code: "class A { static { this.eval(); } }", parserOptions: { ecmaVersion: 2022 } },
 
         // Allows indirect eval
         { code: "(0, eval)('foo')", options: [{ allowIndirect: true }] },
@@ -132,6 +133,12 @@ ruleTester.run("no-eval", rule, {
             code: "class C { [this.eval('foo')] }",
             parserOptions: { ecmaVersion: 2022 },
             errors: [{ messageId: "unexpected" }]
+        },
+
+        {
+            code: "class A { static {} [this.eval()]; }",
+            parserOptions: { ecmaVersion: 2022 },
+            errors: [{ messageId: "unexpected" }]
         }
     ]
 });

tests/lib/rules/no-invalid-this.js

@@ -775,6 +775,54 @@ const patterns = [
         valid: [NORMAL], // the global this in non-strict mode is OK.
         invalid: [USE_STRICT, IMPLIED_STRICT, MODULES],
         errors: [{ messageId: "unexpectedThis", type: "ThisExpression" }]
+    },
+
+    // Class static blocks
+    {
+        code: "class C { static { this.x; } }",
+        parserOptions: { ecmaVersion: 2022 },
+        valid: [NORMAL, USE_STRICT, IMPLIED_STRICT, MODULES],
+        invalid: []
+    },
+    {
+        code: "class C { static { () => { this.x; } } }",
+        parserOptions: { ecmaVersion: 2022 },
+        valid: [NORMAL, USE_STRICT, IMPLIED_STRICT, MODULES],
+        invalid: []
+    },
+    {
+        code: "class C { static { class D { [this.x]; } } }",
+        parserOptions: { ecmaVersion: 2022 },
+        valid: [NORMAL, USE_STRICT, IMPLIED_STRICT, MODULES],
+        invalid: []
+    },
+    {
+        code: "class C { static { function foo() { this.x; } } }",
+        parserOptions: { ecmaVersion: 2022 },
+        valid: [],
+        invalid: [NORMAL, USE_STRICT, IMPLIED_STRICT, MODULES],
+        errors: [{ messageId: "unexpectedThis", type: "ThisExpression" }]
+    },
+    {
+        code: "class C { static { (function() { this.x; }); } }",
+        parserOptions: { ecmaVersion: 2022 },
+        valid: [],
+        invalid: [NORMAL, USE_STRICT, IMPLIED_STRICT, MODULES],
+        errors: [{ messageId: "unexpectedThis", type: "ThisExpression" }]
+    },
+    {
+        code: "class C { static { (function() { this.x; })(); } }",
+        parserOptions: { ecmaVersion: 2022 },
+        valid: [],
+        invalid: [NORMAL, USE_STRICT, IMPLIED_STRICT, MODULES],
+        errors: [{ messageId: "unexpectedThis", type: "ThisExpression" }]
+    },
+    {
+        code: "class C { static {} [this.x]; }",
+        parserOptions: { ecmaVersion: 2022 },
+        valid: [NORMAL],
+        invalid: [USE_STRICT, IMPLIED_STRICT, MODULES],
+        errors: [{ messageId: "unexpectedThis", type: "ThisExpression" }]
     }
 ];