change Erlang code generation

CHANGELOG.md

@@ -456,6 +456,18 @@
   definitions for records with a field named `constructor`.
   ([Giacomo Cavalieri](https://github.com/giacomocavalieri))
 
+- Fixed a bug where the compiler would generate invalid code for `let assert`
+  expression with bit array patterns.
+  ([Giacomo Cavalieri](https://github.com/giacomocavalieri))
+
+- Fixed a bug where the compiler would evaluate the numerator and denominator
+  of a division in the wrong order.
+  ([Giacomo Cavalieri](https://github.com/giacomocavalieri))
+
+- Fixed a bug where the compiler would generate Erlang code that raises further
+  warnings for unused values.
+  ([Giacomo Cavalieri](https://github.com/giacomocavalieri))
+
 - Fixed a bug where the compiler would raise a warning for truncated int
   segments when compiling a function with a JavaScript external.
   ([Giacomo Cavalieri](https://github.com/giacomocavalieri))

Cargo.toml

@@ -17,6 +17,8 @@ members = [
   "hexpm",
   "pretty-arena",
   "format",
+  "erlang-term-format",
+  "erlang-generation",
 ]
 
 # common dependencies
@@ -81,8 +83,8 @@ opener = "0"
 ignore = "0"
 # Parsing of arbitrary width int values
 num-bigint = { version = "0.4.6", features = ["serde"] }
+num-traits = "0.2.19"
 # Unicode grapheme traversal
 unicode-segmentation = "1.13.2"
 # Checksums
 xxhash-rust = { version = "0", features = ["xxh3"] }
-

compiler-cli/src/lib.rs

@@ -50,7 +50,8 @@
     clippy::match_single_binding,
     clippy::inconsistent_struct_constructor,
     clippy::assign_op_pattern,
-    clippy::len_without_is_empty
+    clippy::len_without_is_empty,
+    clippy::let_unit_value
 )]
 
 #[cfg(test)]

compiler-core/Cargo.toml

@@ -37,7 +37,6 @@ pathdiff = { version = "0", features = ["camino"] }
 id-arena = "2"
 # Bijective (bi-directional) hashmap
 bimap = { version = "0.6.3", features = ["serde"] }
-num-traits = "0.2.19"
 # Encryption
 age = { version = "0.11", features = ["armor"] }
 radix_trie = "0.3"
@@ -50,6 +49,7 @@ sourcemap = "9"
 indexmap = "2.12.1"
 
 num-bigint.workspace = true
+num-traits.workspace = true
 async-trait.workspace = true
 base16.workspace = true
 camino = { workspace = true, features = ["serde1"] }
@@ -60,6 +60,7 @@ flate2.workspace = true
 futures.workspace = true
 hexpm = { path = "../hexpm" }
 pretty-arena = { path = "../pretty-arena" }
+erlang-generation = { path = "../erlang-generation" }
 http.workspace = true
 im.workspace = true
 itertools.workspace = true

compiler-core/src/ast/typed.rs

@@ -1021,6 +1021,8 @@ impl TypedExpr {
         matches!(self, Self::Pipeline { .. })
     }
 
+    /// Returns true if this function is guaranteed to not have any side
+    /// effects.
     pub fn is_pure_value_constructor(&self) -> bool {
         match self {
             TypedExpr::Int { .. }
@@ -1046,10 +1048,8 @@ impl TypedExpr {
             // long as it's not called!
             TypedExpr::ModuleSelect { .. } => true,
 
-            // A pipeline is a pure value constructor if its last step is a record builder,
-            // or a call to a pure function. For example:
-            //  - `wibble() |> wobble() |> Ok`
-            //  - `"hello" |> fn(s) { s <> " world!" }`
+            // A pipeline is a pure value constructor if all of its steps are
+            // pure.
             TypedExpr::Pipeline {
                 first_value,
                 assignments,
@@ -1063,6 +1063,9 @@ impl TypedExpr {
                     && finally.is_pure_value_constructor()
             }
 
+            // A function is a pure value constructor if it is a record builder,
+            // or the called function is understood to be pure. Also all of its
+            // arguments must be pure value constructors!
             TypedExpr::Call { fun, arguments, .. } => {
                 (fun.is_record_literal() || fun.called_function_purity().is_pure())
                     && arguments
@@ -1091,9 +1094,9 @@ impl TypedExpr {
                     && clauses.iter().all(|c| c.then.is_pure_value_constructor())
             }
 
-            // `panic`, `todo`, and placeholders are never considered pure value constructors,
-            // we don't want to raise a warning for an unused value if it's one
-            // of those.
+            // `panic`, `todo`, and placeholders are never considered pure value
+            // constructors, we don't want to raise a warning for an unused
+            // value if it's one of those.
             TypedExpr::Todo { .. }
             | TypedExpr::Panic { .. }
             | TypedExpr::Echo { .. }

compiler-core/src/codegen.rs

@@ -61,7 +61,7 @@ impl<'a> Erlang<'a> {
         let line_numbers = LineNumbers::new(&module.code);
         let output = erlang::module(&module.ast, &line_numbers, root);
         tracing::debug!(name = ?name, "Generated Erlang module");
-        writer.write(&path, &output?)
+        writer.write(&path, &output)
     }
 
     fn erlang_record_headers<Writer: FileSystemWriter>(