diff --git a/compiler/load/src/file.rs b/compiler/load/src/file.rs
index 11c30c2dc7..eb77687428 100644
--- a/compiler/load/src/file.rs
+++ b/compiler/load/src/file.rs
@@ -3409,8 +3409,7 @@ fn fabricate_pkg_config_module<'a>(
     header_src: &'a str,
     module_timing: ModuleTiming,
 ) -> (ModuleId, Msg<'a>) {
-    let provides: &'a [Located<ExposesEntry<'a, &'a str>>] =
-        header.provides.items;
+    let provides: &'a [Located<ExposesEntry<'a, &'a str>>] = header.provides.items;
 
     let info = PlatformHeaderInfo {
         filename,
diff --git a/compiler/parse/src/header.rs b/compiler/parse/src/header.rs
index 37475ebce1..f7ec7139b9 100644
--- a/compiler/parse/src/header.rs
+++ b/compiler/parse/src/header.rs
@@ -117,7 +117,7 @@ pub struct PackageHeader<'a> {
     pub after_imports: &'a [CommentOrNewline<'a>],
 }
 
-#[derive(Clone, Debug, PartialEq)]
+#[derive(Copy, Clone, Debug, PartialEq)]
 pub enum PlatformRigid<'a> {
     Entry { rigid: &'a str, alias: &'a str },
 
@@ -137,7 +137,7 @@ impl<'a> Spaceable<'a> for PlatformRigid<'a> {
 
 #[derive(Clone, Debug, PartialEq)]
 pub struct PlatformRequires<'a> {
-    pub rigids: Vec<'a, Loc<PlatformRigid<'a>>>,
+    pub rigids: Collection<'a, Loc<PlatformRigid<'a>>>,
     pub signature: Loc<TypedIdent<'a>>,
 }
 
diff --git a/compiler/parse/src/module.rs b/compiler/parse/src/module.rs
index 4a31995e91..e6a8d9a6e3 100644
--- a/compiler/parse/src/module.rs
+++ b/compiler/parse/src/module.rs
@@ -444,15 +444,17 @@ fn platform_requires<'a>() -> impl Parser<'a, PlatformRequires<'a>, ERequires<'a
 #[inline(always)]
 fn requires_rigids<'a>(
     min_indent: u16,
-) -> impl Parser<'a, Vec<'a, Located<PlatformRigid<'a>>>, ERequires<'a>> {
-    collection_e!(
+) -> impl Parser<'a, Collection<'a, Located<PlatformRigid<'a>>>, ERequires<'a>> {
+    collection_trailing_sep_e!(
         word1(b'{', ERequires::ListStart),
         specialize(|_, r, c| ERequires::Rigid(r, c), loc!(requires_rigid())),
         word1(b',', ERequires::ListEnd),
         word1(b'}', ERequires::ListEnd),
         min_indent,
+        ERequires::Open,
         ERequires::Space,
-        ERequires::IndentListEnd
+        ERequires::IndentListEnd,
+        PlatformRigid::SpaceBefore
     )
 }
 
diff --git a/compiler/parse/src/parser.rs b/compiler/parse/src/parser.rs
index 4b0270e74a..1c176893d5 100644
--- a/compiler/parse/src/parser.rs
+++ b/compiler/parse/src/parser.rs
@@ -243,6 +243,7 @@ pub enum EExposes {
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub enum ERequires<'a> {
     Requires(Row, Col),
+    Open(Row, Col),
     IndentRequires(Row, Col),
     IndentListStart(Row, Col),
     IndentListEnd(Row, Col),
diff --git a/compiler/parse/tests/test_parse.rs b/compiler/parse/tests/test_parse.rs
index b3b3779bd4..5a194088f5 100644
--- a/compiler/parse/tests/test_parse.rs
+++ b/compiler/parse/tests/test_parse.rs
@@ -3318,7 +3318,7 @@ mod test_parse {
             let region2 = Region::new(0, 0, 45, 47);
 
             PlatformRequires {
-                rigids: Vec::new_in(&arena),
+                rigids: Collection::empty(),
                 signature: Located::at(
                     region1,
                     TypedIdent::Entry {
@@ -3403,7 +3403,13 @@ mod test_parse {
             let region3 = Region::new(1, 1, 14, 26);
 
             PlatformRequires {
-                rigids: bumpalo::vec![ in &arena; Located::at(region3, PlatformRigid::Entry { alias: "Model", rigid: "model" }) ],
+                rigids: Collection::with_items(arena.alloc([Located::at(
+                    region3,
+                    PlatformRigid::Entry {
+                        alias: "Model",
+                        rigid: "model",
+                    },
+                )])),
                 signature: Located::at(
                     region1,
                     TypedIdent::Entry {