Add disappeared-use support to identifier-usage-analyzer

Co-authored-by: jackfirth <[email protected]>

Author: Copilot

default-recommendations/analyzers/identifier-usage-test.rkt

@@ -390,3 +390,19 @@ analysis-test: "disappeared use of macro"
 @inspect - m
 @property usage-count
 @assert 1
+
+
+analysis-test: "custom macro with disappeared use"
+--------------------
+(require (for-syntax racket/base))
+(define x 42)
+(define-syntax (use-x stx)
+  (syntax-case stx ()
+    [(_ body)
+     (syntax-property #'body 'disappeared-use (list #'x))]))
+(use-x (void))
+--------------------
+@within - (define x 42)
+@inspect - x
+@property usage-count
+@assert 1

default-recommendations/analyzers/identifier-usage.rkt

@@ -58,6 +58,27 @@
   (extract-ids origin))
 
 
+;; Extract identifiers from the 'disappeared-use syntax property
+;; The 'disappeared-use property can be either:
+;; - A single identifier
+;; - A list of identifiers
+;; We extract all identifiers and label them with the given phase
+(define (disappeared-use-property-identifiers stx phase)
+  (define disappeared (syntax-property stx 'disappeared-use))
+  
+  (define (extract-ids obj)
+    (cond
+      [(not obj) (stream)]
+      [(identifier? obj)
+       ;; Add the phase property to the identifier so it matches correctly
+       (stream (syntax-property obj 'phase phase))]
+      [(list? obj)
+       (apply stream-append (map extract-ids obj))]
+      [else (stream)]))
+  
+  (extract-ids disappeared))
+
+
 ;; Find all identifier usage sites (not binding sites)
 (define (usage-site-identifiers expanded-stx)
   (let loop ([expanded-stx expanded-stx] [phase 0])
@@ -70,6 +91,12 @@
              (for/list ([stx-node (in-stream (syntax-search-everything expanded-stx))])
                (origin-property-identifiers stx-node phase))))
 
+    ;; Collect identifiers from disappeared-use properties of all syntax objects
+    (define disappeared-ids
+      (apply stream-append
+             (for/list ([stx-node (in-stream (syntax-search-everything expanded-stx))])
+               (disappeared-use-property-identifiers stx-node phase))))
+    
     ;; Collect identifiers from the expanded syntax tree
     (define expanded-ids
       (syntax-search expanded-stx
@@ -126,7 +153,7 @@
          #:when (identifier? this-syntax)
          (stream (attribute id))]))
 
-    (stream-append origin-ids expanded-ids)))
+    (stream-append origin-ids disappeared-ids expanded-ids)))
 
 
 (define (fully-expanded-syntax-binding-table stx)