Analysis detects unbound identifiers in well-formed `letrec` expressions

[thalesfm]

Bindings in letrec should be initialized immediately after evaluating their corresponding expression. Currently, the bindings are being initialized only after evaluating all expressions. The following example demonstrates this problem:

(compute-type
 '(letrec ([f (lambda (x) 10)])
           [x (f 11)])
    x))

The code above should evaluate to (type-of 10) but evaluates to ⊥ instead.