Add instantiate shortcuts (#422)

Closes #418.

Author: jackfirth

default-recommendations/class-shortcuts-test.rkt

@@ -27,3 +27,32 @@ test: "two-method nested send expression not refactorable to send+"
 (define (f obj x y)
   (send (send obj m1 x) m2 y))
 --------------------
+
+
+test: "instantiate without by-name arguments refactorable to make-object"
+--------------------
+(define (f cls x y z)
+  (instantiate cls (x y z)))
+--------------------
+--------------------
+(define (f cls x y z)
+  (make-object cls x y z))
+--------------------
+
+
+test: "instantiate without by-position arguments refactorable to new"
+--------------------
+(define (f cls x y z)
+  (instantiate cls () [x x] [y y] [z z]))
+--------------------
+--------------------
+(define (f cls x y z)
+  (new cls [x x] [y y] [z z]))
+--------------------
+
+
+test: "instantiate without any arguments not refactorable"
+--------------------
+(define (f cls)
+  (instantiate cls ()))
+--------------------

default-recommendations/class-shortcuts.rkt

@@ -42,5 +42,23 @@
   (send+ chain.initial-object (chain.method chain.arg ...) ...))
 
 
+(define-refactoring-rule instantiate-to-make-object
+  #:description "The `instantiate` form is for mixing positional and by-name constructor arguments.\
+ When no by-name arguments are needed, use `make-object` instead."
+  #:literals (instantiate)
+  (instantiate cls (by-position-arg ...+))
+  (make-object cls by-position-arg ...))
+
+
+(define-refactoring-rule instantiate-to-new
+  #:description "The `instantiate` form is for mixing positional and by-name constructor arguments.\
+ When no positional arguments are needed, use `new` instead."
+  #:literals (instantiate)
+  (instantiate cls () by-name-arg ...+)
+  (new cls by-name-arg ...))
+
+
 (define-refactoring-suite class-shortcuts
-  #:rules (send-chain-to-send+))
+  #:rules (instantiate-to-make-object
+           instantiate-to-new
+           send-chain-to-send+))