Enlarge smallvec.

Author: cjgillot

src/librustc/hir/lowering.rs

@@ -3298,7 +3298,7 @@ fn body_ids(bodies: &BTreeMap<hir::BodyId, hir::Body<'hir>>) -> Vec<hir::BodyId>
 
 /// Helper struct for delayed construction of GenericArgs.
 struct GenericArgsCtor<'hir> {
-    args: SmallVec<[hir::GenericArg<'hir>; 1]>,
+    args: SmallVec<[hir::GenericArg<'hir>; 4]>,
     bindings: &'hir [hir::TypeBinding<'hir>],
     parenthesized: bool,
 }

src/librustc/hir/lowering/item.rs

@@ -1424,7 +1424,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
 
 /// Helper struct for delayed construction of Generics.
 pub(super) struct GenericsCtor<'hir> {
-    pub(super) params: SmallVec<[hir::GenericParam<'hir>; 1]>,
+    pub(super) params: SmallVec<[hir::GenericParam<'hir>; 4]>,
     where_clause: hir::WhereClause<'hir>,
     span: Span,
 }