From c5637a877d08c156d2c5193927b5e181a9b52d5f Mon Sep 17 00:00:00 2001
From: jbrockmendel <jbrockmendel@gmail.com>
Date: Tue, 6 Oct 2020 15:52:57 -0700
Subject: [PATCH] REF: IntervalIndex.equals defer to IntervalArray.equals
 (#36871)

---
 pandas/core/arrays/_mixins.py   |  9 +++++++++
 pandas/core/arrays/interval.py  | 10 ++++++++++
 pandas/core/indexes/interval.py | 13 ++-----------
 3 files changed, 21 insertions(+), 11 deletions(-)

diff --git a/pandas/core/arrays/_mixins.py b/pandas/core/arrays/_mixins.py
index 4d13a18c8ef0b..95a003efbe1d0 100644
--- a/pandas/core/arrays/_mixins.py
+++ b/pandas/core/arrays/_mixins.py
@@ -8,7 +8,9 @@
 from pandas.util._decorators import cache_readonly, doc
 from pandas.util._validators import validate_fillna_kwargs
 
+from pandas.core.dtypes.common import is_dtype_equal
 from pandas.core.dtypes.inference import is_array_like
+from pandas.core.dtypes.missing import array_equivalent
 
 from pandas.core import missing
 from pandas.core.algorithms import take, unique
@@ -115,6 +117,13 @@ def T(self: _T) -> _T:
 
     # ------------------------------------------------------------------------
 
+    def equals(self, other) -> bool:
+        if type(self) is not type(other):
+            return False
+        if not is_dtype_equal(self.dtype, other.dtype):
+            return False
+        return bool(array_equivalent(self._ndarray, other._ndarray))
+
     def _values_for_argsort(self):
         return self._ndarray
 
diff --git a/pandas/core/arrays/interval.py b/pandas/core/arrays/interval.py
index 94c6c5aed9c0d..a06e0c74ec03b 100644
--- a/pandas/core/arrays/interval.py
+++ b/pandas/core/arrays/interval.py
@@ -706,6 +706,16 @@ def astype(self, dtype, copy=True):
             msg = f"Cannot cast {type(self).__name__} to dtype {dtype}"
             raise TypeError(msg) from err
 
+    def equals(self, other) -> bool:
+        if type(self) != type(other):
+            return False
+
+        return bool(
+            self.closed == other.closed
+            and self.left.equals(other.left)
+            and self.right.equals(other.right)
+        )
+
     @classmethod
     def _concat_same_type(cls, to_concat):
         """
diff --git a/pandas/core/indexes/interval.py b/pandas/core/indexes/interval.py
index 4a877621a94c2..e7747761d2a29 100644
--- a/pandas/core/indexes/interval.py
+++ b/pandas/core/indexes/interval.py
@@ -997,19 +997,10 @@ def equals(self, other: object) -> bool:
         if self.is_(other):
             return True
 
-        # if we can coerce to an IntervalIndex then we can compare
         if not isinstance(other, IntervalIndex):
-            if not is_interval_dtype(other):
-                return False
-            other = Index(other)
-            if not isinstance(other, IntervalIndex):
-                return False
+            return False
 
-        return (
-            self.left.equals(other.left)
-            and self.right.equals(other.right)
-            and self.closed == other.closed
-        )
+        return self._data.equals(other._data)
 
     # --------------------------------------------------------------------
     # Set Operations