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Compute type tooltips better for macro expansions

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Macros often expand into forms where the subforms have
the same syntax location as the entire form, which means
a naive approach gives confusing type tooltips on macro
expressions.

Instead, only keep the latest (outermost) type tooltip
for a given expression.

We could instead compute whether a given piece of syntax
is a subform of another at a given location or not, but
that check is expensive and we don't want to do that on
every update of the type table.

original commit: c2abbc700d6b8233e4a52f518d8056579d696b5f
This commit is contained in:
Asumu Takikawa 2014-11-17 19:40:31 -05:00
parent 0c5d2297cb
commit d02b540d0b
1 changed files with 54 additions and 33 deletions
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87
pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/types/type-table.rkt
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@ -34,13 +34,29 @@
(provide ;; Syntax class for is-ignored?
ignore-table^)
(define table (make-hasheq))
(define type-table (make-hasheq))
(define (reset-type-table) (set! table (make-hasheq)))
;; This table keeps track of the same types as the type table
;; but indexed on source location for tooltips and only retaining the
;; last type for a given location.
(define tooltip-table (make-hash))
(define (reset-type-table) (set! type-table (make-hasheq)))
(define (add-typeof-expr e t)
(when (and (syntax-position e) (syntax-span e))
;; Only keep the latest type for a given location, which means that
;; since typechecking proceeds inside-out we will only record the most
;; relevant type for the expansion of macros (which often have misleading
;; syntax locations on the subexpressions). A limitation of this approach
;; is that for function bodies we may not retain all the types from case->
;; branches.
(hash-set!
tooltip-table
(list (syntax-position e) (syntax-span e))
(list e t)))
(when (optimize?)
(hash-update! table e
(hash-update! type-table e
;; when typechecking a case-> type, types get added for
;; the same subexpression multiple times, combine them
(lambda (old)
@ -59,7 +75,7 @@
t)))
(define (type-of e)
(hash-ref table e
(hash-ref type-table e
(lambda () (int-err (format "no type for ~a at: ~a line ~a col ~a"
(syntax->datum e)
(syntax-source e)
@ -77,10 +93,10 @@
(define (type-table->tooltips)
(define type-names (current-type-names))
(for/fold ([tooltips '()])
([(stx results) (in-hash table)]
#:when (and (syntax-position stx)
(syntax-span stx))
#:unless (error-at-stx-loc? stx))
([(pos+span stx+results) (in-hash tooltip-table)]
#:unless (error-at-stx-loc? (car stx+results)))
(match-define (list pos span) pos+span)
(match-define (list stx results) stx+results)
;; `printed-type-thunks` is #f if we should skip the type because it's
;; something not worth printing like Bottom or Error.
(define printed-type-thunks
@ -103,34 +119,39 @@
#:indent 2)))))]
[(tc-any-results: _) "AnyValues"]))
(cond [(not printed-type-thunks) tooltips]
;; Put the tooltip only on the parens for compound expressions
;; but put them on the whole expression for literals. This avoids
;; overlapping tooltips.
[(or (not (pair? (syntax-e stx)))
;; special-case quote because there's no worry of overlap
;; in a (quote ...) and because literals expand out to a
;; use of quote.
(let ([fst (car (syntax-e stx))])
(and (identifier? fst)
(free-identifier=? fst #'quote))))
(cons (vector stx
(sub1 (syntax-position stx))
(+ (sub1 (syntax-position stx)) (syntax-span stx))
printed-type-thunks)
tooltips)]
[else
(list* (vector stx
(sub1 (syntax-position stx))
(syntax-position stx)
printed-type-thunks)
(vector stx
(sub1 (+ (sub1 (syntax-position stx))
(syntax-span stx)))
(+ (sub1 (syntax-position stx))
(syntax-span stx))
printed-type-thunks)
(append (make-tooltip-vector stx printed-type-thunks pos span)
tooltips)])))
;; make-tooltip-vector : Syntax Thunk Int Int -> (Listof Vector)
;; Compute the tooltip info to put in syntax properties
(define (make-tooltip-vector stx type-thunk position span)
(cond ;; Put the tooltip only on the parens for compound expressions
;; but put them on the whole expression for literals. This avoids
;; overlapping tooltips.
[(or (not (pair? (syntax-e stx)))
;; special-case quote because there's no worry of overlap
;; in a (quote ...) and because literals expand out to a
;; use of quote.
(let ([fst (car (syntax-e stx))])
(and (identifier? fst)
(free-identifier=? fst #'quote))))
(list (vector stx
(sub1 (syntax-position stx))
(+ (sub1 (syntax-position stx)) (syntax-span stx))
type-thunk))]
[else
(list (vector stx
(sub1 (syntax-position stx))
(syntax-position stx)
type-thunk)
(vector stx
(sub1 (+ (sub1 (syntax-position stx))
(syntax-span stx)))
(+ (sub1 (syntax-position stx))
(syntax-span stx))
type-thunk))]))
;; For expressions in test position keep track of if it evaluates to true/false
(define test-position-table/true (make-hasheq))
(define test-position-table/false (make-hasheq))