Crash 'Should have LHS line'

[Wilfred]

See sly commit 57b6d3fd2d4634313cd23c83a3fbd7fa53ad55a4.

[Wilfred]

Minimal repro:

old.lisp:

(defimplementation frame-source-location (index)
  (let ((frame (nth-frame index)))
    (or (source-location (nth-frame index))
        )))

(defimplementation restart-frame (frame-number)
  )
                          
;;;; Compiler hooks

new.lisp:

(defun frame-function (frame)
  )
       
(defimplementation frame-source-location (index)
  (let ((frame (nth-frame index)))
    (or (source-location (nth-frame index))
        )))


;;;; Compiler hooks

[Wilfred]

Smaller:

(foo
  (
    (
        )))

;z
                          
;x

After:

;y

(foo
  (
    (
        )))


;x

[Wilfred]

Fixed in the above commit.