diff --git a/Cargo.lock b/Cargo.lock
index f72d02c..755731e 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -67,6 +67,18 @@ version = "1.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "cf1de2fe8c75bc145a2f577add951f8134889b4795d47466a54a5c846d691693"
 
+[[package]]
+name = "bitvec"
+version = "0.19.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a7ba35e9565969edb811639dbebfe34edc0368e472c5018474c8eb2543397f81"
+dependencies = [
+ "funty",
+ "radium",
+ "tap",
+ "wyz",
+]
+
 [[package]]
 name = "bstr"
 version = "0.2.14"
@@ -314,7 +326,20 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "44533bbbb3bb3c1fa17d9f2e4e38bbbaf8396ba82193c4cb1b6445d711445d36"
 dependencies = [
  "atty",
- "humantime",
+ "humantime 1.3.0",
+ "log",
+ "regex",
+ "termcolor",
+]
+
+[[package]]
+name = "env_logger"
+version = "0.8.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "54532e3223c5af90a6a757c90b5c5521564b07e5e7a958681bcd2afad421cdcd"
+dependencies = [
+ "atty",
+ "humantime 2.0.1",
  "log",
  "regex",
  "termcolor",
@@ -335,6 +360,12 @@ version = "1.0.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "3f9eec918d3f24069decb9af1554cad7c880e2da24a9afd88aca000531ab82c1"
 
+[[package]]
+name = "funty"
+version = "1.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0ba62103ce691c2fd80fbae2213dfdda9ce60804973ac6b6e97de818ea7f52c8"
+
 [[package]]
 name = "getrandom"
 version = "0.1.15"
@@ -396,6 +427,12 @@ dependencies = [
  "quick-error",
 ]
 
+[[package]]
+name = "humantime"
+version = "2.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3c1ad908cc71012b7bea4d0c53ba96a8cba9962f048fa68d143376143d863b7a"
+
 [[package]]
 name = "ident_case"
 version = "1.0.1"
@@ -499,10 +536,11 @@ dependencies = [
 
 [[package]]
 name = "nom"
-version = "5.1.2"
+version = "6.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ffb4262d26ed83a1c0a33a38fe2bb15797329c85770da05e6b828ddb782627af"
+checksum = "4489ccc7d668957ddf64af7cd027c081728903afa6479d35da7e99bf5728f75f"
 dependencies = [
+ "bitvec",
  "lexical-core",
  "memchr",
  "version_check",
@@ -669,6 +707,12 @@ dependencies = [
  "proc-macro2 1.0.24",
 ]
 
+[[package]]
+name = "radium"
+version = "0.5.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "941ba9d78d8e2f7ce474c015eea4d9c6d25b6a3327f9832ee29a4de27f91bbb8"
+
 [[package]]
 name = "rand"
 version = "0.7.3"
@@ -902,6 +946,12 @@ dependencies = [
  "unicode-xid 0.2.1",
 ]
 
+[[package]]
+name = "tap"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "36474e732d1affd3a6ed582781b3683df3d0563714c59c39591e8ff707cf078e"
+
 [[package]]
 name = "tempfile"
 version = "3.1.0"
@@ -1006,7 +1056,7 @@ dependencies = [
  "bstr",
  "clap",
  "clap-verbosity-flag",
- "env_logger",
+ "env_logger 0.8.1",
  "ignore",
  "log",
  "phf",
@@ -1071,7 +1121,7 @@ dependencies = [
  "clap",
  "clap-verbosity-flag",
  "codegenrs",
- "env_logger",
+ "env_logger 0.7.1",
  "itertools",
  "log",
  "phf",
@@ -1220,3 +1270,9 @@ name = "winapi-x86_64-pc-windows-gnu"
 version = "0.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "712e227841d057c1ee1cd2fb22fa7e5a5461ae8e48fa2ca79ec42cfc1931183f"
+
+[[package]]
+name = "wyz"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "85e60b0d1b5f99db2556934e21937020776a5d31520bf169e851ac44e6420214"
diff --git a/Cargo.toml b/Cargo.toml
index 80500cc..168dffb 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -44,7 +44,7 @@ ignore = "0.4"
 serde = { version = "1.0", features = ["derive"] }
 toml = "0.5"
 log = "0.4"
-env_logger = "0.7"
+env_logger = "0.8"
 bstr = "0.2"
 
 [dev-dependencies]
diff --git a/azure-pipelines.yml b/azure-pipelines.yml
index e387fce..b8ed1fd 100644
--- a/azure-pipelines.yml
+++ b/azure-pipelines.yml
@@ -10,7 +10,7 @@ schedules:
     include:
     - master
 variables:
-  minrust: 1.42.0
+  minrust: 1.47.0
   codecov_token: $(CODECOV_TOKEN_SECRET)
   windows_vm: vs2017-win2016
   mac_vm: macos-10.14
diff --git a/crates/varcon-core/Cargo.toml b/crates/varcon-core/Cargo.toml
index e4af268..5929c04 100644
--- a/crates/varcon-core/Cargo.toml
+++ b/crates/varcon-core/Cargo.toml
@@ -19,7 +19,7 @@ parser = ["nom"]
 flags = ["enumflags2"]
 
 [dependencies]
-nom = { version = "5.1.2", optional = true }
+nom = { version = "6", optional = true }
 enumflags2 = { version = "0.6", optional = true }
 
 [package.metadata.docs.rs]
diff --git a/crates/varcon-core/src/parser.rs b/crates/varcon-core/src/parser.rs
index 14a9fad..ba517ae 100644
--- a/crates/varcon-core/src/parser.rs
+++ b/crates/varcon-core/src/parser.rs
@@ -81,7 +81,7 @@ impl Cluster {
                 nom::character::streaming::line_ending,
             ),
         );
-        let cluster = nom::sequence::tuple((
+        let mut cluster = nom::sequence::tuple((
             nom::combinator::opt(header),
             nom::multi::many1(nom::sequence::terminated(
                 Entry::parse,
@@ -156,8 +156,7 @@ impl Entry {
             nom::bytes::streaming::tag("/"),
             nom::character::streaming::space0,
         ));
-        let (input, variants) =
-            nom::multi::separated_nonempty_list(var_sep, Variant::parse)(input)?;
+        let (input, variants) = nom::multi::separated_list1(var_sep, Variant::parse)(input)?;
 
         let desc_sep = nom::sequence::tuple((
             nom::character::streaming::space0,
@@ -320,8 +319,7 @@ mod test_entry {
 
 impl Variant {
     pub fn parse(input: &str) -> IResult<&str, Self> {
-        let types =
-            nom::multi::separated_nonempty_list(nom::character::streaming::space1, Type::parse);
+        let types = nom::multi::separated_list1(nom::character::streaming::space1, Type::parse);
         let sep = nom::sequence::tuple((
             nom::bytes::streaming::tag(":"),
             nom::character::streaming::space0,