From 29a01b801063f661c396980810ffbebfd54a8fce Mon Sep 17 00:00:00 2001
From: Alexander T <alexander.tarasyuk@outlook.com>
Date: Wed, 28 Aug 2019 21:30:23 +0300
Subject: [PATCH] fix(eslint-plugin): [unbound-method] false positive in
 equality comparisons (#914)

---
 packages/eslint-plugin/src/rules/unbound-method.ts   |  3 +++
 .../eslint-plugin/tests/rules/unbound-method.test.ts | 12 ++++++++++++
 2 files changed, 15 insertions(+)

diff --git a/packages/eslint-plugin/src/rules/unbound-method.ts b/packages/eslint-plugin/src/rules/unbound-method.ts
index 8be7a842c46..46bbe779c66 100644
--- a/packages/eslint-plugin/src/rules/unbound-method.ts
+++ b/packages/eslint-plugin/src/rules/unbound-method.ts
@@ -123,6 +123,9 @@ function isSafeUse(node: TSESTree.Node): boolean {
     case AST_NODE_TYPES.UnaryExpression:
       return parent.operator === 'typeof';
 
+    case AST_NODE_TYPES.BinaryExpression:
+      return ['instanceof', '==', '!=', '===', '!=='].includes(parent.operator);
+
     case AST_NODE_TYPES.TSNonNullExpression:
     case AST_NODE_TYPES.TSAsExpression:
     case AST_NODE_TYPES.TSTypeAssertion:
diff --git a/packages/eslint-plugin/tests/rules/unbound-method.test.ts b/packages/eslint-plugin/tests/rules/unbound-method.test.ts
index 2c0d1aaf188..520b28fc1d1 100644
--- a/packages/eslint-plugin/tests/rules/unbound-method.test.ts
+++ b/packages/eslint-plugin/tests/rules/unbound-method.test.ts
@@ -52,15 +52,27 @@ instance.unbound\`\`;
 if (instance.bound) { }
 if (instance.unbound) { }
 
+if (instance.bound !== undefined) { }
+if (instance.unbound !== undefined) { }
+
 if (ContainsMethods.boundStatic) { }
 if (ContainsMethods.unboundStatic) { }
 
+if (ContainsMethods.boundStatic !== undefined) { }
+if (ContainsMethods.unboundStatic !== undefined) { }
+
 while (instance.bound) { }
 while (instance.unbound) { }
 
+while (instance.bound !== undefined) { }
+while (instance.unbound !== undefined) { }
+
 while (ContainsMethods.boundStatic) { }
 while (ContainsMethods.unboundStatic) { }
 
+while (ContainsMethods.boundStatic !== undefined) { }
+while (ContainsMethods.unboundStatic !== undefined) { }
+
 instance.bound as any;
 ContainsMethods.boundStatic as any;