diff --git a/core/compiler/src/solver.rs b/core/compiler/src/solver.rs
index d68e58c..5b16cbf 100644
--- a/core/compiler/src/solver.rs
+++ b/core/compiler/src/solver.rs
@@ -94,10 +94,7 @@ impl Solver {
         let id = self.next_constraint;
         self.next_constraint += 1;
         for (_, var) in &expr.coeffs {
-            self.var_to_constraints
-                .entry(*var)
-                .or_insert(IndexSet::new())
-                .insert(id);
+            self.var_to_constraints.entry(*var).or_default().insert(id);
         }
         self.constraints.insert(id, expr);
         // Use explicit stack in heap-allocated vector to avoid stack overflow.
diff --git a/core/compiler/src/std/lib.ar b/core/compiler/src/std/lib.ar
index b3b41e6..c4788a8 100644
--- a/core/compiler/src/std/lib.ar
+++ b/core/compiler/src/std/lib.ar
@@ -87,7 +87,15 @@ fn array2(r: Rect, nx: Int, ny: Int, xpitch: Float, ypitch: Float) -> Rect {
 fn max_array(r: Rect, w: Float, h: Float, xpitch: Float, ypitch: Float) -> Rect {
     let nx = (((w - r.w) / xpitch) as Int + 1);
     let ny = (((h - r.h) / ypitch) as Int + 1);
-    #scope0 array2(r, nx, ny, xpitch, ypitch)
+    if nx >= 1 {
+        if ny >= 1 {
+            #scope0 array2(r, nx, ny, xpitch, ypitch)
+        } else {
+            crect(w=0., h=0.)
+        }
+    } else {
+        crect(w=0., h=0.)
+    }
 }
 
 fn eq_rect(r1: Rect, r2: Rect) {