diff --git a/compiler/mono/src/ir.rs b/compiler/mono/src/ir.rs
index 49d080b7b4..2d4bfc607c 100644
--- a/compiler/mono/src/ir.rs
+++ b/compiler/mono/src/ir.rs
@@ -5928,6 +5928,13 @@ pub fn from_can<'a>(
                             let _res =
                                 roc_unify::unify::unify(env.subs, var, def.expr_var, Mode::EQ);
 
+                            resolve_abilities_in_specialized_body(
+                                env,
+                                procs,
+                                &def.loc_expr.value,
+                                def.expr_var,
+                            );
+
                             return with_hole(
                                 env,
                                 def.loc_expr.value,
@@ -5959,6 +5966,13 @@ pub fn from_can<'a>(
                                     Mode::EQ,
                                 );
 
+                                resolve_abilities_in_specialized_body(
+                                    env,
+                                    procs,
+                                    &def.loc_expr.value,
+                                    def.expr_var,
+                                );
+
                                 stmt = with_hole(
                                     env,
                                     specialized_expr,
@@ -6017,6 +6031,13 @@ pub fn from_can<'a>(
                 let outer_symbol = env.unique_symbol();
                 stmt = store_pattern(env, procs, layout_cache, &mono_pattern, outer_symbol, stmt);
 
+                resolve_abilities_in_specialized_body(
+                    env,
+                    procs,
+                    &def.loc_expr.value,
+                    def.expr_var,
+                );
+
                 // convert the def body, store in outer_symbol
                 with_hole(
                     env,
diff --git a/compiler/test_gen/src/gen_abilities.rs b/compiler/test_gen/src/gen_abilities.rs
index 5974ddcf04..bd2fa3e852 100644
--- a/compiler/test_gen/src/gen_abilities.rs
+++ b/compiler/test_gen/src/gen_abilities.rs
@@ -292,9 +292,10 @@ fn decode() {
             fromBytes = \lst, fmt ->
                 when decodeWith lst decoder fmt is
                     { result, rest } ->
-                        when result is
-                            Ok val -> if List.isEmpty rest then Ok val else Err (Leftover rest)
-                            Err e -> Err e
+                        Result.after result \val ->
+                            if List.isEmpty rest
+                            then Ok val
+                            else Err (Leftover rest)
 
 
             Linear := {}
@@ -309,9 +310,8 @@ fn decode() {
 
             # impl Decoding for MyU8
             decoder = @Decoder \lst, fmt ->
-                when decodeWith lst u8 fmt is
-                    { result, rest } ->
-                        { result: Result.map result (\n -> @MyU8 n), rest }
+                { result, rest } = decodeWith lst u8 fmt
+                { result: Result.map result (\n -> @MyU8 n), rest }
 
             myU8 =
                 when fromBytes [ 15 ] (@Linear {}) is