Solve and gen ability members that bind other able variables

compiler/can/src/def.rs

@@ -578,8 +578,10 @@ fn resolve_abilities<'a>(
 
             // What variables in the annotation are bound to the parent ability, and what variables
             // are bound to some other ability?
-            let (variables_bound_to_ability, variables_bound_to_other_abilities): (Vec<_>, Vec<_>) =
-                member_annot
+            let (variables_bound_to_ability, _variables_bound_to_other_abilities): (
+                Vec<_>,
+                Vec<_>,
+            ) = member_annot
                 .introduced_variables
                 .able
                 .iter()
@@ -618,18 +620,6 @@ fn resolve_abilities<'a>(
                 bad_has_clauses = true;
             }
 
-            if !variables_bound_to_other_abilities.is_empty() {
-                // Disallow variables bound to other abilities, for now.
-                for bad_variable in variables_bound_to_other_abilities.iter() {
-                    env.problem(Problem::AbilityMemberBindsExternalAbility {
-                        member: member_sym,
-                        ability: loc_ability_name.value,
-                        region: bad_variable.first_seen,
-                    });
-                }
-                bad_has_clauses = true;
-            }
-
             if bad_has_clauses {
                 // Pretend the member isn't a part of the ability
                 continue;

compiler/can/src/traverse.rs

@@ -45,11 +45,12 @@ fn walk_def<V: Visitor>(visitor: &mut V, def: &Def) {
         ..
     } = def;
 
-    visitor.visit_pattern(
-        &loc_pattern.value,
-        loc_pattern.region,
-        loc_pattern.value.opt_var(),
-    );
+    let opt_var = match loc_pattern.value {
+        Pattern::Identifier(..) | Pattern::AbilityMemberSpecialization { .. } => Some(*expr_var),
+        _ => loc_pattern.value.opt_var(),
+    };
+
+    visitor.visit_pattern(&loc_pattern.value, loc_pattern.region, opt_var);
     visitor.visit_expr(&loc_expr.value, loc_expr.region, *expr_var);
     if let Some(annot) = &annotation {
         visitor.visit_annotation(annot);
@@ -70,6 +71,9 @@ fn walk_expr<V: Visitor>(visitor: &mut V, expr: &Expr) {
         } => {
             walk_when(visitor, *cond_var, *expr_var, loc_cond, branches);
         }
+        Expr::Call(f, loc_args, _) => {
+            walk_call(visitor, f, loc_args);
+        }
         e => todo!("{:?}", e),
     }
 }
@@ -120,6 +124,18 @@ fn walk_when_branch<V: Visitor>(visitor: &mut V, branch: &WhenBranch, expr_var:
     }
 }
 
+fn walk_call<V: Visitor>(
+    visitor: &mut V,
+    f: &(Variable, Loc<Expr>, Variable, Variable),
+    loc_args: &[(Variable, Loc<Expr>)],
+) {
+    let (fn_var, loc_fn_expr, _lambda_set, _ret) = f;
+    visitor.visit_expr(&loc_fn_expr.value, loc_fn_expr.region, *fn_var);
+    loc_args
+        .iter()
+        .for_each(|(v, e)| visitor.visit_expr(&e.value, e.region, *v));
+}
+
 fn walk_pattern<V: Visitor>(_visitor: &mut V, _pat: &Pattern) {
     todo!()
 }

compiler/mono/src/ir.rs

@@ -4922,6 +4922,14 @@ fn get_specialization<'a>(
         Some(member) => {
             let snapshot = env.subs.snapshot();
             instantiate_rigids(env.subs, member.signature_var);
+            let this_f = env.subs.get_content_without_compacting(symbol_var);
+            let member_f = env
+                .subs
+                .get_content_without_compacting(member.signature_var);
+            use roc_types::subs::SubsFmtContent;
+            let this_f = SubsFmtContent(&this_f, env.subs);
+            let member_f = SubsFmtContent(&member_f, env.subs);
+            dbg!(symbol, this_f, member_f);
             let (_, must_implement_ability) = unify(
                 env.subs,
                 symbol_var,

compiler/solve/src/ability.rs

@@ -173,9 +173,12 @@ pub fn type_implementing_member(
             let ability_implementations_for_specialization =
                 specialization_must_implement_constraints
                     .clone()
-                    .get_unique();
+                    .get_unique()
+                    .into_iter()
+                    .filter(|mia| mia.ability == ability)
+                    .count();
 
-            ability_implementations_for_specialization.len()
+            ability_implementations_for_specialization
         },
         1,
         "Multiple variables bound to an ability - this is ambiguous and should have been caught in canonicalization: {:?}",

compiler/solve/tests/solve_expr.rs

@@ -25,7 +25,8 @@ mod solve_expr {
     // HELPERS
 
     lazy_static! {
-        static ref RE_TYPE_QUERY: Regex = Regex::new(r#"^\s*#\s*(?P<where>\^+)\s*$"#).unwrap();
+        static ref RE_TYPE_QUERY: Regex =
+            Regex::new(r#"(?P<where>\^+)(?:\{-(?P<sub>\d+)\})?"#).unwrap();
     }
 
     #[derive(Debug, Clone, Copy)]
@@ -35,9 +36,14 @@ mod solve_expr {
         let line_info = LineInfo::new(src);
         let mut queries = vec![];
         for (i, line) in src.lines().enumerate() {
-            if let Some(capture) = RE_TYPE_QUERY.captures(line) {
+            for capture in RE_TYPE_QUERY.captures_iter(line) {
                 let wher = capture.name("where").unwrap();
+                let subtract_col = capture
+                    .name("sub")
+                    .and_then(|m| str::parse(m.as_str()).ok())
+                    .unwrap_or(0);
                 let (start, end) = (wher.start() as u32, wher.end() as u32);
+                let (start, end) = (start - subtract_col, end - subtract_col);
                 let last_line = i as u32 - 1;
                 let start_lc = LineColumn {
                     line: last_line,
@@ -273,7 +279,8 @@ mod solve_expr {
             let start = region.start().offset;
             let end = region.end().offset;
             let text = &src[start as usize..end as usize];
-            let var = find_type_at(region, &decls).expect(&format!("No type for {}!", &text));
+            let var = find_type_at(region, &decls)
+                .expect(&format!("No type for {} ({:?})!", &text, region));
 
             name_all_type_vars(var, subs);
             let content = subs.get_content_without_compacting(var);
@@ -6232,6 +6239,38 @@ mod solve_expr {
                 "#
             ),
             "F b -> b",
+        );
+    }
+
+    #[test]
+    fn ability_member_takes_different_able_variable() {
+        infer_queries(
+            indoc!(
+                r#"
+                app "test" provides [ result ] to "./platform"
+
+                Hash has hash : a -> U64 | a has Hash
+
+                IntoHash has intoHash : a, b -> b | a has IntoHash, b has Hash
+
+                Id := U64
+                hash = \$Id n -> n
+                #^^^^{-1}
+
+                User := Id
+                intoHash = \$User id, _ -> id
+                #^^^^^^^^{-1}
+
+                result = hash (intoHash ($User ($Id 123)) ($Id 1))
+                #        ^^^^  ^^^^^^^^
+                "#
+            ),
+            &[
+                "hash : Id -> U64",
+                "intoHash : User, Id -> Id",
+                "hash : Id -> U64",
+                "intoHash : User, Id -> Id",
+            ],
         )
     }
 

compiler/test_gen/src/gen_abilities.rs

@@ -216,3 +216,29 @@ fn ability_used_as_type_still_compiles() {
         u64
     )
 }
+
+#[test]
+#[cfg(any(feature = "gen-llvm", feature = "gen-wasm"))]
+fn ability_member_takes_different_able_variable() {
+    assert_evals_to!(
+        indoc!(
+            r#"
+            app "test" provides [ result ] to "./platform"
+
+            Hash has hash : a -> U64 | a has Hash
+
+            IntoHash has intoHash : a, b -> b | a has IntoHash, b has Hash
+
+            Id := U64
+            hash = \$Id n -> n
+
+            User := Id
+            intoHash = \$User id, _ -> id
+
+            result = hash (intoHash ($User ($Id 123)) ($Id 1))
+            "#
+        ),
+        123,
+        u64
+    )
+}