```ucm
scratch/main> builtins.merge
```

```unison
one.foo : Nat
one.foo = 17

two.foo : Text
two.foo = "blah"
```

```ucm
scratch/main> add
```

```unison
one.foo : Nat
one.foo = 18

bar : Nat
bar = foo + foo
```

  Loading changes detected in scratch.u.

  I couldn't figure out what foo refers to here:
  
      5 | bar = foo + foo
  
  The name foo is ambiguous. Its type should be: Nat
  
  I found some terms in scope that have matching names and
  types. Maybe you meant one of these:
  
  one.foo : Nat
  one.foo : Nat