diff --git a/compiler/can/src/def.rs b/compiler/can/src/def.rs
index 1c8f99f3ff..0c44cebd0d 100644
--- a/compiler/can/src/def.rs
+++ b/compiler/can/src/def.rs
@@ -1642,7 +1642,11 @@ fn make_tag_union_recursive<'a>(
             can_report_error,
         ),
         _ => {
-            let problem = roc_types::types::Problem::CyclicAlias(symbol, region, others.clone());
+            let problem = roc_types::types::Problem::CyclicAlias(
+                symbol,
+                region,
+                others.clone().into_boxed_slice(),
+            );
             *typ = Type::Erroneous(problem);
 
             // ensure cyclic error is only reported for one element of the cycle
diff --git a/compiler/reporting/src/error/canonicalize.rs b/compiler/reporting/src/error/canonicalize.rs
index 1a259cb8f6..25ea1cf7ed 100644
--- a/compiler/reporting/src/error/canonicalize.rs
+++ b/compiler/reporting/src/error/canonicalize.rs
@@ -146,7 +146,7 @@ pub fn can_problem<'b>(
             },
         ),
         Problem::CyclicAlias(symbol, region, others) => {
-            let (doc, title) = crate::error::r#type::cyclic_alias(alloc, symbol, region, others);
+            let (doc, title) = crate::error::r#type::cyclic_alias(alloc, symbol, region, &*others);
 
             return Report {
                 title,
diff --git a/compiler/reporting/src/error/type.rs b/compiler/reporting/src/error/type.rs
index e5c6763279..529ecbe1ac 100644
--- a/compiler/reporting/src/error/type.rs
+++ b/compiler/reporting/src/error/type.rs
@@ -91,7 +91,7 @@ pub fn type_problem<'b>(
                     }
                 }
                 CyclicAlias(symbol, region, others) => {
-                    let (doc, title) = cyclic_alias(alloc, symbol, region, others);
+                    let (doc, title) = cyclic_alias(alloc, symbol, region, &*others);
 
                     Report {
                         title,
@@ -110,7 +110,7 @@ pub fn cyclic_alias<'b>(
     alloc: &'b RocDocAllocator<'b>,
     symbol: Symbol,
     region: roc_region::all::Region,
-    others: Vec<Symbol>,
+    others: &[Symbol],
 ) -> (RocDocBuilder<'b>, String) {
     let doc = if others.is_empty() {
         alloc.stack(vec![
@@ -140,7 +140,7 @@ pub fn cyclic_alias<'b>(
                 alloc.symbol_unqualified(symbol),
                 others
                     .into_iter()
-                    .map(|other| alloc.symbol_unqualified(other))
+                    .map(|other| alloc.symbol_unqualified(*other))
                     .collect::<Vec<_>>(),
             ),
             alloc.reflow("Recursion in aliases is only allowed if recursion happens behind a tag."),
diff --git a/compiler/solve/tests/solve_expr.rs b/compiler/solve/tests/solve_expr.rs
index 55cbeef6c9..7ccc1f2910 100644
--- a/compiler/solve/tests/solve_expr.rs
+++ b/compiler/solve/tests/solve_expr.rs
@@ -4497,8 +4497,9 @@ mod solve_expr {
             std::mem::size_of::<roc_types::subs::Content>(),
             std::mem::size_of::<roc_types::subs::FlatType>(),
             std::mem::size_of::<roc_types::types::Problem>(),
+            std::mem::size_of::<roc_module::ident::Ident>(),
         );
 
-        assert_eq!(query, (40, 96, 80, 72, 64))
+        assert_eq!(query, (40, 96, 80, 72, 64, 32))
     }
 }
diff --git a/compiler/types/src/types.rs b/compiler/types/src/types.rs
index 5859862e03..91643ddecb 100644
--- a/compiler/types/src/types.rs
+++ b/compiler/types/src/types.rs
@@ -1117,7 +1117,7 @@ pub struct Alias {
 pub enum Problem {
     CanonicalizationProblem,
     CircularType(Symbol, Box<ErrorType>, Region),
-    CyclicAlias(Symbol, Region, Vec<Symbol>),
+    CyclicAlias(Symbol, Region, Box<[Symbol]>),
     UnrecognizedIdent(InlinableString),
     Shadowed(Region, Located<Ident>),
     BadTypeArguments {