Dedup keys when parsing shape maps in ELP

Summary: The Erlang spec allows users to define map types with duplicate keys, wherte the leftmost definition takes precedence. This will be later disallowed in eqWAlizer, but for now, we need to ensure parsing deals with these cases correctly.

Reviewed By: ilya-klyuchnikov, VLanvin

Differential Revision: D59802368

fbshipit-source-id: f551fe2503b1a0e75e998bc732abefb1317bbffa

crates/eqwalizer/Cargo.toml

@@ -11,6 +11,7 @@ elp_types_db.workspace = true
 anyhow.workspace = true
 eetf.workspace = true
 fxhash.workspace = true
+itertools.workspace = true
 lazy_static.workspace = true
 log.workspace = true
 parking_lot.workspace = true

crates/eqwalizer/src/ast/convert_types.rs

@@ -45,6 +45,7 @@ use elp_types_db::eqwalizer::types::Type;
 use elp_types_db::eqwalizer::types::UnionType;
 use elp_types_db::eqwalizer::types::VarType;
 use fxhash::FxHashMap;
+use itertools::Itertools;
 
 use super::TypeConversionError;
 
@@ -353,6 +354,12 @@ impl TypeConverter {
                     let props = ty
                         .props
                         .into_iter()
+                        .unique_by(|prop| {
+                            let ExtType::AtomLitExtType(atom_ty) = prop.key() else {
+                                panic!("Illegal state: is_shape implies key is always an atom")
+                            };
+                            atom_ty.atom.clone()
+                        })
                         .map(|prop| self.to_shape_prop(sub, prop))
                         .collect::<Result<Result<Vec<_>, _>, _>>()?;
                     Ok(props.map(|props| Type::ShapeMap(ShapeMap { props })))

test_projects/eqwalizer_tests/check/src/other.erl

@@ -49,3 +49,6 @@ any_as_metadata_neg(M) -> M.
 elab_var_scope(_) ->
     (begin X = 3, X, fun () -> ok end end)(),
     X.
+
+-spec map_with_dup_keys(#{ak => av1, bk => bv1, ak => av2}) -> #{ak => av1, bk => bv1}.
+map_with_dup_keys(M) -> M.