diff --git a/ast/Cargo.toml b/ast/Cargo.toml
index d1384b96ee..546b8dd81a 100644
--- a/ast/Cargo.toml
+++ b/ast/Cargo.toml
@@ -3,7 +3,7 @@ name = "roc_ast"
 version = "0.1.0"
 authors = ["The Roc Contributors"]
 license = "UPL-1.0"
-edition = "2018"
+edition = "2021"
 description = "AST as used by the editor and (soon) docs. In contrast to the compiler, these types do not keep track of a location in a file."
 
 [dependencies]
diff --git a/bindgen/Cargo.toml b/bindgen/Cargo.toml
index 37b7f4def1..f5b93a2be8 100644
--- a/bindgen/Cargo.toml
+++ b/bindgen/Cargo.toml
@@ -4,7 +4,7 @@ version = "0.1.0"
 authors = ["The Roc Contributors"]
 license = "UPL-1.0"
 repository = "https://github.com/rtfeldman/roc"
-edition = "2018"
+edition = "2021"
 description = "A CLI for roc-bindgen"
 
 [[bin]]
diff --git a/ci/bench-runner/Cargo.toml b/ci/bench-runner/Cargo.toml
index 02e775065f..8449107831 100644
--- a/ci/bench-runner/Cargo.toml
+++ b/ci/bench-runner/Cargo.toml
@@ -1,7 +1,7 @@
 [package]
 name = "bench-runner"
 version = "0.1.0"
-edition = "2018"
+edition = "2021"
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
diff --git a/cli/Cargo.toml b/cli/Cargo.toml
index 9cedf556fd..848564ac35 100644
--- a/cli/Cargo.toml
+++ b/cli/Cargo.toml
@@ -4,7 +4,7 @@ version = "0.1.0"
 authors = ["The Roc Contributors"]
 license = "UPL-1.0"
 repository = "https://github.com/rtfeldman/roc"
-edition = "2018"
+edition = "2021"
 description = "A CLI for Roc"
 default-run = "roc"
 
diff --git a/cli_utils/Cargo.toml b/cli_utils/Cargo.toml
index 0f009564c7..3b9fd9a73c 100644
--- a/cli_utils/Cargo.toml
+++ b/cli_utils/Cargo.toml
@@ -4,7 +4,7 @@ version = "0.1.0"
 authors = ["The Roc Contributors"]
 license = "UPL-1.0"
 repository = "https://github.com/rtfeldman/roc"
-edition = "2018"
+edition = "2021"
 description = "Shared code for cli tests and benchmarks"
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
diff --git a/code_markup/Cargo.toml b/code_markup/Cargo.toml
index 07eb0aa4d7..0a18868e9b 100644
--- a/code_markup/Cargo.toml
+++ b/code_markup/Cargo.toml
@@ -3,7 +3,7 @@ name = "roc_code_markup"
 version = "0.1.0"
 authors = ["The Roc Contributors"]
 license = "UPL-1.0"
-edition = "2018"
+edition = "2021"
 description = "Our own markup language for Roc code. Used by the editor and the docs."
 
 [dependencies]
diff --git a/compiler/alias_analysis/Cargo.toml b/compiler/alias_analysis/Cargo.toml
index 8777595cbf..98fd17f6f8 100644
--- a/compiler/alias_analysis/Cargo.toml
+++ b/compiler/alias_analysis/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 authors = ["The Roc Contributors"]
-edition = "2018"
+edition = "2021"
 license = "UPL-1.0"
 name = "roc_alias_analysis"
 version = "0.1.0"
diff --git a/compiler/arena_pool/Cargo.toml b/compiler/arena_pool/Cargo.toml
index 88dcca43f3..f3d0aa6e08 100644
--- a/compiler/arena_pool/Cargo.toml
+++ b/compiler/arena_pool/Cargo.toml
@@ -4,5 +4,5 @@ version = "0.1.0"
 authors = ["The Roc Contributors"]
 license = "UPL-1.0"
 repository = "https://github.com/rtfeldman/roc"
-edition = "2018"
+edition = "2021"
 description = "A CLI for Roc"
diff --git a/compiler/build/Cargo.toml b/compiler/build/Cargo.toml
index 883361fe45..17ff3d5609 100644
--- a/compiler/build/Cargo.toml
+++ b/compiler/build/Cargo.toml
@@ -3,7 +3,7 @@ name = "roc_build"
 version = "0.1.0"
 authors = ["The Roc Contributors"]
 license = "UPL-1.0"
-edition = "2018"
+edition = "2021"
 
 [dependencies]
 roc_collections = { path = "../collections" }
diff --git a/compiler/builtins/Cargo.toml b/compiler/builtins/Cargo.toml
index 36b973cc9e..e14f07a0bd 100644
--- a/compiler/builtins/Cargo.toml
+++ b/compiler/builtins/Cargo.toml
@@ -3,7 +3,7 @@ name = "roc_builtins"
 version = "0.1.0"
 authors = ["The Roc Contributors"]
 license = "UPL-1.0"
-edition = "2018"
+edition = "2021"
 
 [dependencies]
 roc_collections = { path = "../collections" }
diff --git a/compiler/can/Cargo.toml b/compiler/can/Cargo.toml
index b57aba90ad..79d99d746e 100644
--- a/compiler/can/Cargo.toml
+++ b/compiler/can/Cargo.toml
@@ -3,7 +3,7 @@ name = "roc_can"
 version = "0.1.0"
 authors = ["The Roc Contributors"]
 license = "UPL-1.0"
-edition = "2018"
+edition = "2021"
 
 [dependencies]
 roc_collections = { path = "../collections" }
diff --git a/compiler/collections/Cargo.toml b/compiler/collections/Cargo.toml
index 6cd46e1101..454e0bc8b6 100644
--- a/compiler/collections/Cargo.toml
+++ b/compiler/collections/Cargo.toml
@@ -3,7 +3,7 @@ name = "roc_collections"
 version = "0.1.0"
 authors = ["The Roc Contributors"]
 license = "UPL-1.0"
-edition = "2018"
+edition = "2021"
 
 [dependencies]
 im    = "15.0.0"
diff --git a/compiler/constrain/Cargo.toml b/compiler/constrain/Cargo.toml
index d5c4059c63..94ebd2ce4b 100644
--- a/compiler/constrain/Cargo.toml
+++ b/compiler/constrain/Cargo.toml
@@ -3,7 +3,7 @@ name = "roc_constrain"
 version = "0.1.0"
 authors = ["The Roc Contributors"]
 license = "UPL-1.0"
-edition = "2018"
+edition = "2021"
 
 [dependencies]
 roc_collections = { path = "../collections" }
diff --git a/compiler/exhaustive/Cargo.toml b/compiler/exhaustive/Cargo.toml
index 7fa1a63bda..a0cbbaf717 100644
--- a/compiler/exhaustive/Cargo.toml
+++ b/compiler/exhaustive/Cargo.toml
@@ -3,7 +3,7 @@ name = "roc_exhaustive"
 version = "0.1.0"
 authors = ["The Roc Contributors"]
 license = "UPL-1.0"
-edition = "2018"
+edition = "2021"
 
 [dependencies]
 roc_collections = { path = "../collections" }
diff --git a/compiler/fmt/Cargo.toml b/compiler/fmt/Cargo.toml
index 815891ba59..a402a79d81 100644
--- a/compiler/fmt/Cargo.toml
+++ b/compiler/fmt/Cargo.toml
@@ -3,7 +3,7 @@ name = "roc_fmt"
 version = "0.1.0"
 authors = ["The Roc Contributors"]
 license = "UPL-1.0"
-edition = "2018"
+edition = "2021"
 
 [dependencies]
 roc_collections = { path = "../collections" }
diff --git a/compiler/gen_dev/Cargo.toml b/compiler/gen_dev/Cargo.toml
index 00b08bd467..ef8f6d1dbd 100644
--- a/compiler/gen_dev/Cargo.toml
+++ b/compiler/gen_dev/Cargo.toml
@@ -4,7 +4,7 @@ description = "The development backend for the Roc compiler"
 version = "0.1.0"
 authors = ["The Roc Contributors"]
 license = "UPL-1.0"
-edition = "2018"
+edition = "2021"
 
 [dependencies]
 roc_collections = { path = "../collections" }
diff --git a/compiler/gen_llvm/Cargo.toml b/compiler/gen_llvm/Cargo.toml
index 5d020a5507..8093e436ed 100644
--- a/compiler/gen_llvm/Cargo.toml
+++ b/compiler/gen_llvm/Cargo.toml
@@ -4,7 +4,7 @@ description = "The LLVM backend for the Roc compiler"
 version = "0.1.0"
 authors = ["The Roc Contributors"]
 license = "UPL-1.0"
-edition = "2018"
+edition = "2021"
 
 [dependencies]
 roc_alias_analysis = { path = "../alias_analysis" }
diff --git a/compiler/gen_wasm/Cargo.toml b/compiler/gen_wasm/Cargo.toml
index ccdb6b2768..5989fb6aa2 100644
--- a/compiler/gen_wasm/Cargo.toml
+++ b/compiler/gen_wasm/Cargo.toml
@@ -1,7 +1,7 @@
 [package]
 name = "roc_gen_wasm"
 version = "0.1.0"
-edition = "2018"
+edition = "2021"
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
diff --git a/compiler/ident/Cargo.toml b/compiler/ident/Cargo.toml
index d272f4818f..70987df20e 100644
--- a/compiler/ident/Cargo.toml
+++ b/compiler/ident/Cargo.toml
@@ -3,4 +3,4 @@ name = "roc_ident"
 version = "0.1.0"
 authors = ["The Roc Contributors"]
 license = "UPL-1.0"
-edition = "2018"
+edition = "2021"
diff --git a/compiler/load/Cargo.toml b/compiler/load/Cargo.toml
index f3d1d4c30f..ec3fae6f05 100644
--- a/compiler/load/Cargo.toml
+++ b/compiler/load/Cargo.toml
@@ -3,7 +3,7 @@ name = "roc_load"
 version = "0.1.0"
 authors = ["The Roc Contributors"]
 license = "UPL-1.0"
-edition = "2018"
+edition = "2021"
 
 [dependencies]
 roc_load_internal = { path = "../load_internal" }
diff --git a/compiler/load_internal/Cargo.toml b/compiler/load_internal/Cargo.toml
index 798c462551..1e171f226b 100644
--- a/compiler/load_internal/Cargo.toml
+++ b/compiler/load_internal/Cargo.toml
@@ -3,7 +3,7 @@ name = "roc_load_internal"
 version = "0.1.0"
 authors = ["The Roc Contributors"]
 license = "UPL-1.0"
-edition = "2018"
+edition = "2021"
 
 [dependencies]
 roc_collections = { path = "../collections" }
diff --git a/compiler/module/Cargo.toml b/compiler/module/Cargo.toml
index 9b8c272d54..26db73eeb1 100644
--- a/compiler/module/Cargo.toml
+++ b/compiler/module/Cargo.toml
@@ -2,7 +2,7 @@
 name = "roc_module"
 version = "0.1.0"
 authors = ["The Roc Contributors"]
-edition = "2018"
+edition = "2021"
 license = "UPL-1.0"
 
 [dependencies]
diff --git a/compiler/mono/Cargo.toml b/compiler/mono/Cargo.toml
index ff32e8e1e9..39ef08944c 100644
--- a/compiler/mono/Cargo.toml
+++ b/compiler/mono/Cargo.toml
@@ -3,7 +3,7 @@ name = "roc_mono"
 version = "0.1.0"
 authors = ["The Roc Contributors"]
 license = "UPL-1.0"
-edition = "2018"
+edition = "2021"
 
 [dependencies]
 roc_collections = { path = "../collections" }
diff --git a/compiler/parse/Cargo.toml b/compiler/parse/Cargo.toml
index 33954d8d95..00e9ce63c9 100644
--- a/compiler/parse/Cargo.toml
+++ b/compiler/parse/Cargo.toml
@@ -3,7 +3,7 @@ name = "roc_parse"
 version = "0.1.0"
 authors = ["The Roc Contributors"]
 license = "UPL-1.0"
-edition = "2018"
+edition = "2021"
 
 [features]
 "parse_debug_trace" = []
diff --git a/compiler/parse/fuzz/Cargo.toml b/compiler/parse/fuzz/Cargo.toml
index 2d1bd145cf..54889585a9 100644
--- a/compiler/parse/fuzz/Cargo.toml
+++ b/compiler/parse/fuzz/Cargo.toml
@@ -3,7 +3,7 @@ name = "roc_parse-fuzz"
 version = "0.0.0"
 authors = ["Automatically generated"]
 publish = false
-edition = "2018"
+edition = "2021"
 
 [package.metadata]
 cargo-fuzz = true
diff --git a/compiler/problem/Cargo.toml b/compiler/problem/Cargo.toml
index af0f1108a0..9aa102ff5f 100644
--- a/compiler/problem/Cargo.toml
+++ b/compiler/problem/Cargo.toml
@@ -3,7 +3,7 @@ name = "roc_problem"
 version = "0.1.0"
 authors = ["The Roc Contributors"]
 license = "UPL-1.0"
-edition = "2018"
+edition = "2021"
 
 [dependencies]
 roc_collections = { path = "../collections" }
diff --git a/compiler/region/Cargo.toml b/compiler/region/Cargo.toml
index ecea4be54a..d80e07b9a0 100644
--- a/compiler/region/Cargo.toml
+++ b/compiler/region/Cargo.toml
@@ -3,7 +3,7 @@ name = "roc_region"
 version = "0.1.0"
 authors = ["The Roc Contributors"]
 license = "UPL-1.0"
-edition = "2018"
+edition = "2021"
 
 [dependencies]
 static_assertions = "1.1.0"
diff --git a/compiler/roc_target/Cargo.toml b/compiler/roc_target/Cargo.toml
index 5ef3aba2d9..6e3bffe5df 100644
--- a/compiler/roc_target/Cargo.toml
+++ b/compiler/roc_target/Cargo.toml
@@ -3,7 +3,7 @@ name = "roc_target"
 version = "0.1.0"
 authors = ["The Roc Contributors"]
 license = "UPL-1.0"
-edition = "2018"
+edition = "2021"
 
 [dependencies]
 target-lexicon = "0.12.3"
diff --git a/compiler/solve/Cargo.toml b/compiler/solve/Cargo.toml
index 8f06caef58..3044589259 100644
--- a/compiler/solve/Cargo.toml
+++ b/compiler/solve/Cargo.toml
@@ -3,7 +3,7 @@ name = "roc_solve"
 version = "0.1.0"
 authors = ["The Roc Contributors"]
 license = "UPL-1.0"
-edition = "2018"
+edition = "2021"
 
 [dependencies]
 roc_collections = { path = "../collections" }
diff --git a/compiler/str/Cargo.toml b/compiler/str/Cargo.toml
index 68e5cfde2e..a59efae3c4 100644
--- a/compiler/str/Cargo.toml
+++ b/compiler/str/Cargo.toml
@@ -3,7 +3,7 @@ name = "roc_str"
 version = "0.1.0"
 authors = ["The Roc Contributors"]
 license = "UPL-1.0"
-edition = "2018"
+edition = "2021"
 
 [dependencies]
 roc_collections = { path = "../collections" }
diff --git a/compiler/test_gen/Cargo.toml b/compiler/test_gen/Cargo.toml
index ff2e79a7b5..2322900e08 100644
--- a/compiler/test_gen/Cargo.toml
+++ b/compiler/test_gen/Cargo.toml
@@ -3,7 +3,7 @@ name = "test_gen"
 version = "0.1.0"
 authors = ["The Roc Contributors"]
 license = "UPL-1.0"
-edition = "2018"
+edition = "2021"
 
 [[test]]
 name = "test_gen"
diff --git a/compiler/test_gen/src/tests.rs b/compiler/test_gen/src/tests.rs
index eb730c7e96..b5ab6f3633 100644
--- a/compiler/test_gen/src/tests.rs
+++ b/compiler/test_gen/src/tests.rs
@@ -60,7 +60,6 @@ pub unsafe fn roc_dealloc(c_ptr: *mut c_void, _alignment: u32) {
 pub unsafe fn roc_panic(c_ptr: *mut c_void, tag_id: u32) {
     use roc_gen_llvm::llvm::build::PanicTagId;
 
-    use std::convert::TryFrom;
     use std::ffi::CStr;
     use std::os::raw::c_char;
 
diff --git a/compiler/test_mono/Cargo.toml b/compiler/test_mono/Cargo.toml
index fb06a403be..eb87b5efa8 100644
--- a/compiler/test_mono/Cargo.toml
+++ b/compiler/test_mono/Cargo.toml
@@ -3,7 +3,7 @@ name = "test_mono"
 version = "0.1.0"
 authors = ["The Roc Contributors"]
 license = "UPL-1.0"
-edition = "2018"
+edition = "2021"
 
 [[test]]
 name = "test_mono"
diff --git a/compiler/test_mono_macros/Cargo.toml b/compiler/test_mono_macros/Cargo.toml
index 8ddad8c85e..c5889844c5 100644
--- a/compiler/test_mono_macros/Cargo.toml
+++ b/compiler/test_mono_macros/Cargo.toml
@@ -3,7 +3,7 @@ name = "test_mono_macros"
 version = "0.1.0"
 authors = ["The Roc Contributors"]
 license = "UPL-1.0"
-edition = "2018"
+edition = "2021"
 
 [lib]
 proc-macro = true
diff --git a/compiler/types/Cargo.toml b/compiler/types/Cargo.toml
index e00c368701..a27e2ad4c9 100644
--- a/compiler/types/Cargo.toml
+++ b/compiler/types/Cargo.toml
@@ -3,7 +3,7 @@ name = "roc_types"
 version = "0.1.0"
 authors = ["The Roc Contributors"]
 license = "UPL-1.0"
-edition = "2018"
+edition = "2021"
 
 [dependencies]
 roc_collections = { path = "../collections" }
diff --git a/compiler/types/src/subs.rs b/compiler/types/src/subs.rs
index 374b5aa3c9..15af9f6101 100644
--- a/compiler/types/src/subs.rs
+++ b/compiler/types/src/subs.rs
@@ -241,7 +241,6 @@ impl Subs {
     }
 
     pub fn deserialize(bytes: &[u8]) -> (Self, &[(Symbol, Variable)]) {
-        use std::convert::TryInto;
 
         let mut offset = 0;
         let header_slice = &bytes[..std::mem::size_of::<SubsHeader>()];
diff --git a/compiler/types/src/types.rs b/compiler/types/src/types.rs
index 0ba04ba799..963694b6c7 100644
--- a/compiler/types/src/types.rs
+++ b/compiler/types/src/types.rs
@@ -1422,7 +1422,7 @@ impl Type {
     pub fn expect_variable(&self, reason: &'static str) -> Variable {
         match self {
             Type::Variable(v) => *v,
-            _ => internal_error!(reason),
+            _ => internal_error!("{}", reason),
         }
     }
 }
diff --git a/compiler/unify/Cargo.toml b/compiler/unify/Cargo.toml
index e92e2aa3e3..3cb709c120 100644
--- a/compiler/unify/Cargo.toml
+++ b/compiler/unify/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 authors = ["The Roc Contributors"]
-edition = "2018"
+edition = "2021"
 license = "UPL-1.0"
 name = "roc_unify"
 version = "0.1.0"
diff --git a/docs/Cargo.toml b/docs/Cargo.toml
index 39e39bb68f..9f41af3a46 100644
--- a/docs/Cargo.toml
+++ b/docs/Cargo.toml
@@ -3,7 +3,7 @@ name = "roc_docs"
 version = "0.1.0"
 license = "UPL-1.0"
 authors = ["The Roc Contributors"]
-edition = "2018"
+edition = "2021"
 
 [dependencies]
 pulldown-cmark = { version = "0.8.0", default-features = false }
diff --git a/docs_cli/Cargo.toml b/docs_cli/Cargo.toml
index 5cf22bf54c..96600f1f17 100644
--- a/docs_cli/Cargo.toml
+++ b/docs_cli/Cargo.toml
@@ -3,7 +3,7 @@ name = "roc_docs_cli"
 version = "0.1.0"
 license = "UPL-1.0"
 authors = ["The Roc Contributors"]
-edition = "2018"
+edition = "2021"
 
 # This binary is only used on static build servers, e.g. Netlify.
 # Having its own (extremely minimal) CLI means docs can be generated
diff --git a/editor/Cargo.toml b/editor/Cargo.toml
index 82128eabef..ef6058bff5 100644
--- a/editor/Cargo.toml
+++ b/editor/Cargo.toml
@@ -3,7 +3,7 @@ name = "roc_editor"
 version = "0.1.0"
 authors = ["The Roc Contributors"]
 license = "UPL-1.0"
-edition = "2018"
+edition = "2021"
 description = "An editor for Roc"
 
 [package.metadata.cargo-udeps.ignore]
diff --git a/error_macros/Cargo.toml b/error_macros/Cargo.toml
index d5c7276898..83744ab39d 100644
--- a/error_macros/Cargo.toml
+++ b/error_macros/Cargo.toml
@@ -3,6 +3,6 @@ name = "roc_error_macros"
 version = "0.1.0"
 authors = ["The Roc Contributors"]
 license = "UPL-1.0"
-edition = "2018"
+edition = "2021"
 
 [dependencies]
diff --git a/examples/breakout/platform/Cargo.toml b/examples/breakout/platform/Cargo.toml
index 47281be89d..566506d6c4 100644
--- a/examples/breakout/platform/Cargo.toml
+++ b/examples/breakout/platform/Cargo.toml
@@ -3,7 +3,7 @@ name = "host"
 version = "0.1.0"
 authors = ["The Roc Contributors"]
 license = "UPL-1.0"
-edition = "2018"
+edition = "2021"
 
 # Needed to be able to run on non-Windows systems for some reason. Without this, cargo panics with:
 #
diff --git a/examples/false-interpreter/platform/Cargo.toml b/examples/false-interpreter/platform/Cargo.toml
index eba1dfa680..37d5561b6b 100644
--- a/examples/false-interpreter/platform/Cargo.toml
+++ b/examples/false-interpreter/platform/Cargo.toml
@@ -3,7 +3,7 @@ name = "host"
 version = "0.1.0"
 authors = ["The Roc Contributors"]
 license = "UPL-1.0"
-edition = "2018"
+edition = "2021"
 
 links = "app"
 
diff --git a/examples/gui/platform/Cargo.toml b/examples/gui/platform/Cargo.toml
index b82712e562..56339e540e 100644
--- a/examples/gui/platform/Cargo.toml
+++ b/examples/gui/platform/Cargo.toml
@@ -3,7 +3,7 @@ name = "host"
 version = "0.1.0"
 authors = ["The Roc Contributors"]
 license = "UPL-1.0"
-edition = "2018"
+edition = "2021"
 links = "app"
 
 # Needed to be able to run on non-Windows systems for some reason. Without this, cargo panics with:
diff --git a/examples/hello-world/rust-platform/Cargo.toml b/examples/hello-world/rust-platform/Cargo.toml
index 72f534c88e..baad986559 100644
--- a/examples/hello-world/rust-platform/Cargo.toml
+++ b/examples/hello-world/rust-platform/Cargo.toml
@@ -3,7 +3,7 @@ name = "host"
 version = "0.1.0"
 authors = ["The Roc Contributors"]
 license = "UPL-1.0"
-edition = "2018"
+edition = "2021"
 links = "app"
 
 [lib]
diff --git a/examples/interactive/cli-platform/Cargo.toml b/examples/interactive/cli-platform/Cargo.toml
index eba1dfa680..37d5561b6b 100644
--- a/examples/interactive/cli-platform/Cargo.toml
+++ b/examples/interactive/cli-platform/Cargo.toml
@@ -3,7 +3,7 @@ name = "host"
 version = "0.1.0"
 authors = ["The Roc Contributors"]
 license = "UPL-1.0"
-edition = "2018"
+edition = "2021"
 
 links = "app"
 
diff --git a/highlight/Cargo.toml b/highlight/Cargo.toml
index aef00a2c33..4cd885c52f 100644
--- a/highlight/Cargo.toml
+++ b/highlight/Cargo.toml
@@ -3,7 +3,7 @@ name = "roc_highlight"
 version = "0.1.0"
 authors = ["The Roc Contributors"]
 license = "UPL-1.0"
-edition = "2018"
+edition = "2021"
 description = "For syntax highlighting, starts with a string and returns our markup nodes."
 
 [dependencies]
diff --git a/linker/Cargo.toml b/linker/Cargo.toml
index 497c8088a1..0952e7d924 100644
--- a/linker/Cargo.toml
+++ b/linker/Cargo.toml
@@ -4,7 +4,7 @@ version = "0.1.0"
 authors = ["The Roc Contributors"]
 license = "UPL-1.0"
 repository = "https://github.com/rtfeldman/roc"
-edition = "2018"
+edition = "2021"
 description = "A surgical linker for Roc"
 
 [lib]
diff --git a/nightly_benches/Cargo.toml b/nightly_benches/Cargo.toml
index 380cb7f454..f37a09f96a 100644
--- a/nightly_benches/Cargo.toml
+++ b/nightly_benches/Cargo.toml
@@ -1,7 +1,7 @@
 [package]
 name = "nightly_benches"
 version = "0.1.0"
-edition = "2018"
+edition = "2021"
 
 [dependencies]
 
diff --git a/reporting/Cargo.toml b/reporting/Cargo.toml
index 9ca5360dc6..107eb05a71 100644
--- a/reporting/Cargo.toml
+++ b/reporting/Cargo.toml
@@ -3,7 +3,7 @@ name = "roc_reporting"
 version = "0.1.0"
 authors = ["The Roc Contributors"]
 license = "UPL-1.0"
-edition = "2018"
+edition = "2021"
 
 [dependencies]
 roc_collections = { path = "../compiler/collections" }
diff --git a/roc_std/Cargo.toml b/roc_std/Cargo.toml
index 22337ad6fb..5f18ae3060 100644
--- a/roc_std/Cargo.toml
+++ b/roc_std/Cargo.toml
@@ -1,7 +1,7 @@
 [package]
 authors = ["The Roc Contributors"]
 description = "Rust representations of Roc data structures"
-edition = "2018"
+edition = "2021"
 license = "UPL-1.0"
 name = "roc_std"
 readme = "README.md"
diff --git a/test_utils/Cargo.toml b/test_utils/Cargo.toml
index 1a2efaceb1..c053106f67 100644
--- a/test_utils/Cargo.toml
+++ b/test_utils/Cargo.toml
@@ -3,7 +3,7 @@ name = "roc_test_utils"
 version = "0.1.0"
 authors = ["The Roc Contributors"]
 license = "UPL-1.0"
-edition = "2018"
+edition = "2021"
 description = "Utility functions used all over the code base."
 
 [dependencies]
diff --git a/utils/Cargo.toml b/utils/Cargo.toml
index 9797265931..de90f5ecd7 100644
--- a/utils/Cargo.toml
+++ b/utils/Cargo.toml
@@ -3,7 +3,7 @@ name = "roc_utils"
 version = "0.1.0"
 authors = ["The Roc Contributors"]
 license = "UPL-1.0"
-edition = "2018"
+edition = "2021"
 description = "Utility functions used all over the code base."
 
 [dependencies]
diff --git a/wasi-libc-sys/Cargo.toml b/wasi-libc-sys/Cargo.toml
index 1732300332..259a38b2cf 100644
--- a/wasi-libc-sys/Cargo.toml
+++ b/wasi-libc-sys/Cargo.toml
@@ -1,7 +1,7 @@
 [package]
 authors = ["The Roc Contributors"]
 description = "Rust wrapper for a WebAssembly test platform built on libc"
-edition = "2018"
+edition = "2021"
 license = "UPL-1.0"
 name = "wasi_libc_sys"
 repository = "https://github.com/rtfeldman/roc"