If we bring out the arguments to a function call, then we can simplify them.
Compare to 27.

-- a.cue --
let x = {a: 5, a: int}
y: len(x)
-- out/trim-v3 --
== a.cue
let x = {a: 5}
y: len(x)
-- diff/-out/trim-v3<==>+out/trim --
diff old new
--- old
+++ new
@@ -1,3 +1,3 @@
 == a.cue
-let x = {a: 5, a: int}
+let x = {a: 5}
 y: len(x)
-- out/trim-v3-noshare --
== a.cue
let x = {a: 5}
y: len(x)
-- diff/-out/trim-v3-noshare<==>+out/trim --
diff old new
--- old
+++ new
@@ -1,3 +1,3 @@
 == a.cue
-let x = {a: 5, a: int}
+let x = {a: 5}
 y: len(x)
-- out/trim --
== a.cue
let x = {a: 5, a: int}
y: len(x)
