diff --git a/.travis.yml b/.travis.yml
index 436476b4..a2898e0d 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -12,12 +12,12 @@ env:
 matrix:
   include:
     - os: osx
-      rust: 1.35.0
+      rust: 1.36.0
       install:
         - cargo fmt --version || rustup component add rustfmt-preview
         - cargo clippy --version || rustup component add clippy-preview
       env: SUITE=ci
-    - rust: 1.35.0
+    - rust: 1.36.0
       addons:
         apt:
           packages:
@@ -28,21 +28,21 @@ matrix:
             - texinfo
             - libtool
       env: SUITE=ci-quick
-    - rust: 1.35.0
+    - rust: 1.36.0
       addons:
         apt:
           packages:
             - git
             - build-essential
       env: SUITE=ci-generated
-    - rust: 1.35.0
+    - rust: 1.36.0
       addons:
         apt:
           packages:
             - git
             - build-essential
       env: SUITE=check
-    - rust: 1.35.0
+    - rust: 1.36.0
       addons:
         apt:
           packages:
@@ -50,7 +50,7 @@ matrix:
             - build-essential
       env: SUITE=ci-all-features
     - os: osx
-      rust: 1.35.0
+      rust: 1.36.0
       addons:
         apt:
           packages:
@@ -58,7 +58,7 @@ matrix:
             - build-essential
       env: SUITE=ci-all-features
     - name: Test Suite
-      rust: 1.35.0
+      rust: 1.36.0
       dist: xenial
       addons:
         apt:
@@ -83,7 +83,7 @@ matrix:
         RISCV=`pwd`/riscv ./ckb-vm-test-suite/test.sh
     - name: Code Coverage
       if: 'tag IS NOT present AND type != pull_request AND (branch = develop OR branch = master)'
-      rust: 1.35.0
+      rust: 1.36.0
       dist: xenial
       addons:
         apt:
diff --git a/Cargo.toml b/Cargo.toml
index 36e80092..9a83b931 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -16,7 +16,6 @@ asm = ["libc", "memmap"]
 byteorder = "1"
 bytes = "0.4.12"
 goblin = "0.0.22"
-hashbrown = "0.5.0"
 memmap = { version = "0.7.0", optional = true }
 libc = { version = "0.2.47", optional = true }
 ckb-vm-definitions = { path = "definitions", version = "0.13.0" }
diff --git a/src/machine/aot/mod.rs b/src/machine/aot/mod.rs
index 74c8a27a..b2800d58 100644
--- a/src/machine/aot/mod.rs
+++ b/src/machine/aot/mod.rs
@@ -11,8 +11,8 @@ use super::super::{
 use bytes::Bytes;
 use emitter::Emitter;
 use goblin::elf::{section_header::SHF_EXECINSTR, Elf};
-use hashbrown::{HashMap, HashSet};
 use memmap::{Mmap, MmapMut};
+use std::collections::{HashMap, HashSet};
 use std::rc::Rc;
 
 const MAXIMUM_INSTRUCTIONS_PER_BLOCK: usize = 1024;