diff --git a/Cargo.lock b/Cargo.lock
index f09ca5f..b000031 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -13,9 +13,9 @@ dependencies = [
 
 [[package]]
 name = "aho-corasick"
-version = "0.7.6"
+version = "0.7.20"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "58fb5e95d83b38284460a5fda7d6470aa0b8844d283a0b614b8535e880800d2d"
+checksum = "cc936419f96fa211c1b9166887b38e5e40b19958e5b895be7c1f93adec7071ac"
 dependencies = [
  "memchr",
 ]
@@ -29,12 +29,6 @@ dependencies = [
  "winapi 0.3.8",
 ]
 
-[[package]]
-name = "approx"
-version = "0.1.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "08abcc3b4e9339e33a3d0a5ed15d84a687350c05689d825e0f6655eef9e76a94"
-
 [[package]]
 name = "arrayref"
 version = "0.3.5"
@@ -140,17 +134,6 @@ version = "1.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "baf1de4339761588bc0619e3cbc0120ee582ebb74b53b4efbf79117bd2da40fd"
 
-[[package]]
-name = "cgmath"
-version = "0.16.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "64a4b57c8f4e3a2e9ac07e0f6abc9c24b6fc9e1b54c3478cfb598f3d0023e51c"
-dependencies = [
- "approx",
- "num-traits 0.1.43",
- "rand 0.4.6",
-]
-
 [[package]]
 name = "cloudabi"
 version = "0.0.3"
@@ -162,12 +145,13 @@ dependencies = [
 
 [[package]]
 name = "colored"
-version = "1.8.0"
+version = "1.9.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6cdb90b60f2927f8d76139c72dbde7e10c3a2bc47c8594c9c7a66529f2687c03"
+checksum = "5a5f741c91823341bebf717d4c71bda820630ce065443b58bd1b7451af008355"
 dependencies = [
+ "is-terminal",
  "lazy_static 1.4.0",
- "winconsole",
+ "winapi 0.3.8",
 ]
 
 [[package]]
@@ -192,8 +176,8 @@ version = "0.1.21"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ccc0a48a9b826acdf4028595adc9db92caea352f7af011a3034acd172a52a0aa"
 dependencies = [
- "quote 1.0.10",
- "syn 1.0.80",
+ "quote",
+ "syn",
 ]
 
 [[package]]
@@ -202,9 +186,9 @@ version = "2.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "fcc3dd5e9e9c0b295d6e1e4d811fb6f157d5ffd784b8d202fc62eac8035a770b"
 dependencies = [
- "proc-macro2 1.0.30",
- "quote 1.0.10",
- "syn 1.0.80",
+ "proc-macro2",
+ "quote",
+ "syn",
 ]
 
 [[package]]
@@ -247,9 +231,9 @@ checksum = "c34f04666d835ff5d62e058c3995147c06f42fe86ff053337632bca83e42702d"
 
 [[package]]
 name = "failure"
-version = "0.1.5"
+version = "0.1.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "795bd83d3abeb9220f257e597aa0080a508b27533824adf336529648f6abf7e2"
+checksum = "d32e9bd16cc02eae7db7ef620b392808b89f6a5e16bb3497d159c6b92a0f4f86"
 dependencies = [
  "backtrace",
  "failure_derive",
@@ -257,13 +241,13 @@ dependencies = [
 
 [[package]]
 name = "failure_derive"
-version = "0.1.5"
+version = "0.1.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ea1063915fd7ef4309e222a5a07cf9c319fb9c7836b1f89b85458672dbb127e1"
+checksum = "aa4da3c766cd7a0db8242e326e9e4e081edd567072893ed320008189715366a4"
 dependencies = [
- "proc-macro2 0.4.30",
- "quote 0.6.13",
- "syn 0.15.44",
+ "proc-macro2",
+ "quote",
+ "syn",
  "synstructure",
 ]
 
@@ -298,6 +282,12 @@ dependencies = [
  "unicode-width",
 ]
 
+[[package]]
+name = "hermit-abi"
+version = "0.3.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d231dfb89cfffdbc30e7fc41579ed6066ad03abda9e567ccafae602b97ec5024"
+
 [[package]]
 name = "includedir"
 version = "0.2.2"
@@ -320,19 +310,30 @@ dependencies = [
 ]
 
 [[package]]
-name = "itertools"
-version = "0.10.1"
+name = "is-terminal"
+version = "0.4.12"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "69ddb889f9d0d08a67338271fa9b62996bc788c7796a5c18cf057420aaed5eaf"
+checksum = "f23ff5ef2b80d608d61efee834934d862cd92461afc0560dedf493e4c033738b"
+dependencies = [
+ "hermit-abi",
+ "libc",
+ "windows-sys",
+]
+
+[[package]]
+name = "itertools"
+version = "0.10.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b0fd2260e829bddf4cb6ea802289de2f86d6a7a690192fbe91b3f46e0f2c8473"
 dependencies = [
  "either",
 ]
 
 [[package]]
 name = "itoa"
-version = "0.4.4"
+version = "1.0.11"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "501266b7edd0174f8530248f87f99c88fbe60ca4ef3dd486835b8d8d53136f7f"
+checksum = "49f1f14873335454500d59611f1cf4a4b0f786f9ac11f4312a78e4cf2566695b"
 
 [[package]]
 name = "kernel32-sys"
@@ -382,7 +383,7 @@ dependencies = [
  "cc",
  "lazy_static 1.4.0",
  "libc",
- "regex 1.3.1",
+ "regex 1.7.3",
  "semver",
 ]
 
@@ -507,7 +508,7 @@ dependencies = [
  "num-integer",
  "num-iter",
  "num-rational",
- "num-traits 0.2.8",
+ "num-traits",
 ]
 
 [[package]]
@@ -517,7 +518,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e63899ad0da84ce718c14936262a41cee2c79c981fc0a0e7c7beb47d5a07e8c1"
 dependencies = [
  "num-integer",
- "num-traits 0.2.8",
+ "num-traits",
  "rand 0.4.6",
  "rustc-serialize",
 ]
@@ -528,7 +529,7 @@ version = "0.1.43"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "b288631d7878aaf59442cffd36910ea604ecd7745c36054328595114001c9656"
 dependencies = [
- "num-traits 0.2.8",
+ "num-traits",
  "rustc-serialize",
 ]
 
@@ -539,7 +540,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "b85e541ef8255f6cf42bbfe4ef361305c6c135d10919ecc26126c4e5ae94bc09"
 dependencies = [
  "autocfg",
- "num-traits 0.2.8",
+ "num-traits",
 ]
 
 [[package]]
@@ -550,7 +551,7 @@ checksum = "76bd5272412d173d6bf9afdf98db8612bbabc9a7a830b7bfc9c188911716132e"
 dependencies = [
  "autocfg",
  "num-integer",
- "num-traits 0.2.8",
+ "num-traits",
 ]
 
 [[package]]
@@ -561,19 +562,10 @@ checksum = "ee314c74bd753fc86b4780aa9475da469155f3848473a261d2d18e35245a784e"
 dependencies = [
  "num-bigint",
  "num-integer",
- "num-traits 0.2.8",
+ "num-traits",
  "rustc-serialize",
 ]
 
-[[package]]
-name = "num-traits"
-version = "0.1.43"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "92e5113e9fd4cc14ded8e499429f396a20f98c772a47cc8622a736e1ec843c31"
-dependencies = [
- "num-traits 0.2.8",
-]
-
 [[package]]
 name = "num-traits"
 version = "0.2.8"
@@ -594,9 +586,9 @@ dependencies = [
 
 [[package]]
 name = "peg"
-version = "0.8.1"
+version = "0.8.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a07f2cafdc3babeebc087e499118343442b742cc7c31b4d054682cc598508554"
+checksum = "295283b02df346d1ef66052a757869b2876ac29a6bb0ac3f5f7cd44aebe40e8f"
 dependencies = [
  "peg-macros",
  "peg-runtime",
@@ -604,20 +596,20 @@ dependencies = [
 
 [[package]]
 name = "peg-macros"
-version = "0.8.1"
+version = "0.8.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4a90084dc05cf0428428e3d12399f39faad19b0909f64fb9170c9fdd6d9cd49b"
+checksum = "bdad6a1d9cf116a059582ce415d5f5566aabcd4008646779dab7fdc2a9a9d426"
 dependencies = [
  "peg-runtime",
- "proc-macro2 1.0.30",
- "quote 1.0.10",
+ "proc-macro2",
+ "quote",
 ]
 
 [[package]]
 name = "peg-runtime"
-version = "0.8.1"
+version = "0.8.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9fa00462b37ead6d11a82c9d568b26682d78e0477dc02d1966c013af80969739"
+checksum = "e3aeb8f54c078314c2065ee649a7241f46b9d8e418e1a9581ba0546657d7aa3a"
 
 [[package]]
 name = "phf"
@@ -669,31 +661,13 @@ dependencies = [
  "output_vt100",
 ]
 
-[[package]]
-name = "proc-macro2"
-version = "0.4.30"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "cf3d2011ab5c909338f7887f4fc896d35932e29146c12c8d01da6b22a80ba759"
-dependencies = [
- "unicode-xid 0.1.0",
-]
-
 [[package]]
 name = "proc-macro2"
 version = "1.0.30"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "edc3358ebc67bc8b7fa0c007f945b0b18226f78437d61bec735a9eb96b61ee70"
 dependencies = [
- "unicode-xid 0.2.0",
-]
-
-[[package]]
-name = "quote"
-version = "0.6.13"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6ce23b6b870e8f94f81fb0a363d65d86675884b34a09043c81e5562f11c1f8e1"
-dependencies = [
- "proc-macro2 0.4.30",
+ "unicode-xid",
 ]
 
 [[package]]
@@ -702,14 +676,14 @@ version = "1.0.10"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "38bc8cc6a5f2e3655e0899c1b848643b2562f853f114bfec7be120678e3ace05"
 dependencies = [
- "proc-macro2 1.0.30",
+ "proc-macro2",
 ]
 
 [[package]]
 name = "radix_trie"
-version = "0.1.5"
+version = "0.1.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "deafbff7bda0a58975ce92723aa18be10eae2e9271f3c3f48de52d131d9f248c"
+checksum = "3d3681b28cd95acfb0560ea9441f82d6a4504fa3b15b97bd7b6e952131820e95"
 dependencies = [
  "endian-type",
  "nibble_vec",
@@ -876,14 +850,13 @@ dependencies = [
 
 [[package]]
 name = "regex"
-version = "1.3.1"
+version = "1.7.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "dc220bd33bdce8f093101afe22a037b8eb0e5af33592e6a9caafff0d4cb81cbd"
+checksum = "8b1f693b24f6ac912f4893ef08244d70b6067480d2f1a46e950c9691e6749d1d"
 dependencies = [
- "aho-corasick 0.7.6",
+ "aho-corasick 0.7.20",
  "memchr",
- "regex-syntax 0.6.12",
- "thread_local",
+ "regex-syntax 0.6.29",
 ]
 
 [[package]]
@@ -897,15 +870,9 @@ dependencies = [
 
 [[package]]
 name = "regex-syntax"
-version = "0.6.12"
+version = "0.6.29"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "11a7e20d1cce64ef2fed88b66d347f88bd9babb82845b2b858f3edbf59a4f716"
-
-[[package]]
-name = "rgb"
-version = "0.8.14"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "2089e4031214d129e201f8c3c8c2fe97cd7322478a0d1cdf78e7029b0042efdb"
+checksum = "f162c6dd7b008981e4d40210aca20b4bd0f9b60ca9271061b07f78537722f2e1"
 
 [[package]]
 name = "rust-argon2"
@@ -926,9 +893,9 @@ checksum = "4c691c0e608126e00913e33f0ccf3727d5fc84573623b8d65b2df340b5201783"
 
 [[package]]
 name = "rustc-serialize"
-version = "0.3.24"
+version = "0.3.25"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "dcf128d1287d2ea9d80910b5f1120d0b8eede3fbf1abe91c40d39ea7d51e6fda"
+checksum = "fe834bc780604f4674073badbad26d7219cadfb4a2275802db12cbae17498401"
 
 [[package]]
 name = "ryu"
@@ -1004,26 +971,26 @@ checksum = "388a1df253eca08550bef6c72392cfe7c30914bf41df5269b68cbd6ff8f570a3"
 
 [[package]]
 name = "serde"
-version = "1.0.101"
+version = "1.0.185"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9796c9b7ba2ffe7a9ce53c2287dfc48080f4b2b362fcc245a259b3a7201119dd"
+checksum = "be9b6f69f1dfd54c3b568ffa45c310d6973a5e5148fd40cf515acaf38cf5bc31"
 
 [[package]]
 name = "serde_derive"
-version = "1.0.101"
+version = "1.0.136"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4b133a43a1ecd55d4086bd5b4dc6c1751c68b1bfbeba7a5040442022c7e7c02e"
+checksum = "08597e7152fcd306f41838ed3e37be9eaeed2b61c42e2117266a554fab4662f9"
 dependencies = [
- "proc-macro2 1.0.30",
- "quote 1.0.10",
- "syn 1.0.80",
+ "proc-macro2",
+ "quote",
+ "syn",
 ]
 
 [[package]]
 name = "serde_json"
-version = "1.0.40"
+version = "1.0.109"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "051c49229f282f7c6f3813f8286cc1e3323e8051823fce42c7ea80fe13521704"
+checksum = "cb0652c533506ad7a2e353cce269330d6afd8bdfb6d75e0ace5b35aacbd7b9e9"
 dependencies = [
  "itoa",
  "ryu",
@@ -1060,38 +1027,27 @@ dependencies = [
  "num",
 ]
 
-[[package]]
-name = "syn"
-version = "0.15.44"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9ca4b3b69a77cbe1ffc9e198781b7acb0c7365a883670e8f1c1bc66fba79a5c5"
-dependencies = [
- "proc-macro2 0.4.30",
- "quote 0.6.13",
- "unicode-xid 0.1.0",
-]
-
 [[package]]
 name = "syn"
 version = "1.0.80"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d010a1623fbd906d51d650a9916aaefc05ffa0e4053ff7fe601167f3e715d194"
 dependencies = [
- "proc-macro2 1.0.30",
- "quote 1.0.10",
- "unicode-xid 0.2.0",
+ "proc-macro2",
+ "quote",
+ "unicode-xid",
 ]
 
 [[package]]
 name = "synstructure"
-version = "0.10.2"
+version = "0.12.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "02353edf96d6e4dc81aea2d8490a7e9db177bf8acb0e951c24940bf866cb313f"
+checksum = "f36bdaa60a83aca3921b5259d5400cbf5e90fc51931376a9bd4a0eb79aa7210f"
 dependencies = [
- "proc-macro2 0.4.30",
- "quote 0.6.13",
- "syn 0.15.44",
- "unicode-xid 0.1.0",
+ "proc-macro2",
+ "quote",
+ "syn",
+ "unicode-xid",
 ]
 
 [[package]]
@@ -1119,9 +1075,9 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "3b114ece25254e97bf48dd4bfc2a12bad0647adacfe4cae1247a9ca6ad302cec"
 dependencies = [
  "cfg-if 1.0.0",
- "proc-macro2 1.0.30",
- "quote 1.0.10",
- "syn 1.0.80",
+ "proc-macro2",
+ "quote",
+ "syn",
  "version_check 0.9.3",
 ]
 
@@ -1155,12 +1111,6 @@ version = "0.1.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7007dbd421b92cc6e28410fe7362e2e0a2503394908f417b68ec8d1c364c4e20"
 
-[[package]]
-name = "unicode-xid"
-version = "0.1.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "fc72304796d0818e357ead4e000d19c9c174ab23dc11093ac919054d20a6a7fc"
-
 [[package]]
 name = "unicode-xid"
 version = "0.2.0"
@@ -1236,13 +1186,74 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "712e227841d057c1ee1cd2fb22fa7e5a5461ae8e48fa2ca79ec42cfc1931183f"
 
 [[package]]
-name = "winconsole"
-version = "0.10.0"
+name = "windows-sys"
+version = "0.52.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3ef84b96d10db72dd980056666d7f1e7663ce93d82fa33b63e71c966f4cf5032"
+checksum = "282be5f36a8ce781fad8c8ae18fa3f9beff57ec1b52cb3de0789201425d9a33d"
 dependencies = [
- "cgmath",
- "lazy_static 1.4.0",
- "rgb",
- "winapi 0.3.8",
+ "windows-targets",
 ]
+
+[[package]]
+name = "windows-targets"
+version = "0.52.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9b724f72796e036ab90c1021d4780d4d3d648aca59e491e6b98e725b84e99973"
+dependencies = [
+ "windows_aarch64_gnullvm",
+ "windows_aarch64_msvc",
+ "windows_i686_gnu",
+ "windows_i686_gnullvm",
+ "windows_i686_msvc",
+ "windows_x86_64_gnu",
+ "windows_x86_64_gnullvm",
+ "windows_x86_64_msvc",
+]
+
+[[package]]
+name = "windows_aarch64_gnullvm"
+version = "0.52.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "32a4622180e7a0ec044bb555404c800bc9fd9ec262ec147edd5989ccd0c02cd3"
+
+[[package]]
+name = "windows_aarch64_msvc"
+version = "0.52.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "09ec2a7bb152e2252b53fa7803150007879548bc709c039df7627cabbd05d469"
+
+[[package]]
+name = "windows_i686_gnu"
+version = "0.52.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8e9b5ad5ab802e97eb8e295ac6720e509ee4c243f69d781394014ebfe8bbfa0b"
+
+[[package]]
+name = "windows_i686_gnullvm"
+version = "0.52.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0eee52d38c090b3caa76c563b86c3a4bd71ef1a819287c19d586d7334ae8ed66"
+
+[[package]]
+name = "windows_i686_msvc"
+version = "0.52.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "240948bc05c5e7c6dabba28bf89d89ffce3e303022809e73deaefe4f6ec56c66"
+
+[[package]]
+name = "windows_x86_64_gnu"
+version = "0.52.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "147a5c80aabfbf0c7d901cb5895d1de30ef2907eb21fbbab29ca94c5b08b1a78"
+
+[[package]]
+name = "windows_x86_64_gnullvm"
+version = "0.52.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "24d5b23dc417412679681396f2b49f3de8c1473deb516bd34410872eff51ed0d"
+
+[[package]]
+name = "windows_x86_64_msvc"
+version = "0.52.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "589f6da84c646204747d1270a2a5661ea66ed1cced2631d546fdfb155959f9ec"
diff --git a/rust-toolchain.toml b/rust-toolchain.toml
new file mode 100644
index 0000000..5d56faf
--- /dev/null
+++ b/rust-toolchain.toml
@@ -0,0 +1,2 @@
+[toolchain]
+channel = "nightly"
diff --git a/schala-lang/src/lib.rs b/schala-lang/src/lib.rs
index d208b6c..9ab0633 100644
--- a/schala-lang/src/lib.rs
+++ b/schala-lang/src/lib.rs
@@ -1,6 +1,6 @@
 #![feature(trace_macros)]
 //#![feature(unrestricted_attribute_tokens)]
-#![feature(box_patterns, box_syntax, iter_intersperse)]
+#![feature(box_patterns, iter_intersperse)]
 
 //! `schala-lang` is where the Schala programming language is actually implemented.
 //! It defines the `Schala` type, which contains the state for a Schala REPL, and implements
diff --git a/schala-lang/src/type_inference/mod.rs b/schala-lang/src/type_inference/mod.rs
index e7f541d..ba22eff 100644
--- a/schala-lang/src/type_inference/mod.rs
+++ b/schala-lang/src/type_inference/mod.rs
@@ -216,12 +216,12 @@ macro_rules! ty {
         Type::Const(crate::type_inference::TypeConst::$type_name)
     };
     ($t1:ident -> $t2:ident) => {
-        Type::Arrow { params: vec![ty!($t1)], ret: box ty!($t2) }
+        Type::Arrow { params: vec![ty!($t1)], ret: Box::new(ty!($t2)) }
     };
     ($t1:ident -> $t2:ident -> $t3:ident) => {
-        Type::Arrow { params: vec![ty!($t1), ty!($t2)], ret: box ty!($t3) }
+        Type::Arrow { params: vec![ty!($t1), ty!($t2)], ret: Box::new(ty!($t3)) }
     };
     ($type_list:ident, $ret_type:ident) => {
-        Type::Arrow { params: $type_list, ret: box $ret_type }
+        Type::Arrow { params: $type_list, ret: Box::new($ret_type) }
     };
 }
diff --git a/schala-repl/src/lib.rs b/schala-repl/src/lib.rs
index 8cba074..c5a7911 100644
--- a/schala-repl/src/lib.rs
+++ b/schala-repl/src/lib.rs
@@ -1,5 +1,4 @@
-#![feature(box_patterns, box_syntax, proc_macro_hygiene, decl_macro, iter_intersperse)]
-#![feature(plugin)]
+#![feature(box_patterns, proc_macro_hygiene, decl_macro, iter_intersperse)]
 
 #[macro_use]
 extern crate serde_derive;