fix(eslint-plugin): [no-unused-vars] handle logical assignment (#7854)

* fix(eslint-plugin): [no-unused-vars] handle logical assignment * refactor

Author: yeonjuan

packages/eslint-plugin/src/util/collectUnusedVariables.ts

@@ -439,6 +439,8 @@ function isExported(variable: TSESLint.Scope.Variable): boolean {
  });
 }
 
+const LOGICAL_ASSIGNMENT_OPERATORS = new Set(['&&=', '||=', '??=']);
+
 /**
  * Determines if the variable is used.
  * @param variable The variable to check.
@@ -701,6 +703,7 @@ function isUsedVariable(variable: TSESLint.Scope.Variable): boolean {
  ref.isRead() && // in RHS of an assignment for itself. e.g. `a = a + 1`
  // self update. e.g. `a += 1`, `a++`
  ((parent.type === AST_NODE_TYPES.AssignmentExpression &&
+ !LOGICAL_ASSIGNMENT_OPERATORS.has(parent.operator) &&
  grandparent.type === AST_NODE_TYPES.ExpressionStatement &&
  parent.left === id) ||
  (parent.type === AST_NODE_TYPES.UpdateExpression &&

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

@@ -1099,6 +1099,18 @@ interface Foo {
  bar: string;
 }
  `,
+ `
+let foo = 1;
+foo ??= 2;
+ `,
+ `
+let foo = 1;
+foo &&= 2;
+ `,
+ `
+let foo = 1;
+foo ||= 2;
+ `,
  ],
 
  invalid: [
@@ -1844,5 +1856,23 @@ const Foo = 'bar';
  },
  ],
  },
+ {
+ code: `
+let foo = 1;
+foo += 1;
+ `,
+ errors: [
+ {
+ messageId: 'unusedVar',
+ line: 3,
+ column: 1,
+ data: {
+ varName: 'foo',
+ action: 'assigned a value',
+ additional: '',
+ },
+ },
+ ],
+ },
  ],
 });