Consolidate let-binding rules into let-replacement directory (#642)

Co-authored-by: copilot-swe-agent[bot] <[email protected]>
Co-authored-by: jackfirth <[email protected]>

Author: Copilot

default-recommendations.rkt

@@ -21,7 +21,10 @@
                resyntax/default-recommendations/legacy-contract-migrations
                resyntax/default-recommendations/legacy-struct-migrations
                resyntax/default-recommendations/legacy-syntax-migrations
-               resyntax/default-recommendations/let-binding-suggestions
+               resyntax/default-recommendations/let-replacement/cond-let-replacement
+               resyntax/default-recommendations/let-replacement/let-binding-suggestions
+               resyntax/default-recommendations/let-replacement/let-replacement
+               resyntax/default-recommendations/let-replacement/match-let-replacement
                resyntax/default-recommendations/list-shortcuts
                resyntax/default-recommendations/loops/for-loop-shortcuts
                resyntax/default-recommendations/loops/list-loopification
@@ -58,7 +61,10 @@
          resyntax/default-recommendations/legacy-contract-migrations
          resyntax/default-recommendations/legacy-struct-migrations
          resyntax/default-recommendations/legacy-syntax-migrations
-         resyntax/default-recommendations/let-binding-suggestions
+         resyntax/default-recommendations/let-replacement/cond-let-replacement
+         resyntax/default-recommendations/let-replacement/let-binding-suggestions
+         resyntax/default-recommendations/let-replacement/let-replacement
+         resyntax/default-recommendations/let-replacement/match-let-replacement
          resyntax/default-recommendations/list-shortcuts
          resyntax/default-recommendations/loops/for-loop-shortcuts
          resyntax/default-recommendations/loops/list-loopification
@@ -83,6 +89,7 @@
             class-shortcuts
             comparison-shortcuts
             conditional-shortcuts
+            cond-let-replacement
             console-io-suggestions
             contract-shortcuts
             definition-shortcuts
@@ -104,8 +111,10 @@
 
             legacy-syntax-migrations
             let-binding-suggestions
+            let-replacement
             list-loopification
             list-shortcuts
+            match-let-replacement
             match-shortcuts
             miscellaneous-suggestions
             mutability-predicates

default-recommendations/conditional-shortcuts-test.rkt

@@ -532,41 +532,6 @@ no-change-test: "`if-else-false-to-and` is not refactorable when `and` is shadow
 ------------------------------
 
 
-test: "cond with nested let refactorable to cond with define"
-------------------------------
-(define (f a c)
-  (cond
-    [a
-     (let ([x "stuff"])
-       x)]
-    [else c]))
-==============================
-(define (f a c)
-  (cond
-    [a
-     (define x "stuff")
-     x]
-    [else c]))
-------------------------------
-
-
-test: "cond with nested let in else clause refactorable to cond with define"
-------------------------------
-(define (f a b)
-  (cond
-    [a b]
-    [else
-     (let ([x "stuff"])
-       x)]))
-==============================
-(define (f a b)
-  (cond
-    [a b]
-    [else
-     (define x "stuff")
-     x]))
-------------------------------
-
 
 test: "if clause with begin in true branch refactorable to cond"
 ------------------------------

default-recommendations/conditional-shortcuts.rkt

@@ -14,7 +14,7 @@
          resyntax/base
          resyntax/default-recommendations/private/boolean
          resyntax/default-recommendations/private/exception
-         resyntax/default-recommendations/private/let-binding
+         resyntax/default-recommendations/let-replacement/private/let-binding
          resyntax/default-recommendations/private/metafunction
          resyntax/default-recommendations/private/syntax-equivalence
          syntax/parse)
@@ -183,21 +183,6 @@
    (~@ . (~splicing-replacement (nested-clause ...) #:original outer-else-clause))))
 
 
-(define-syntax-class let-refactorable-cond-clause
-  #:attributes (refactored)
-  (pattern [condition:expr leading-body ... let-expr:refactorable-let-expression]
-    #:with refactored
-    #`(~replacement
-       [condition leading-body ... (~@ . (~focus-replacement-on (let-expr.refactored ...)))]
-       #:original #,this-syntax)))
-
-
-(define-refactoring-rule cond-let-to-cond-define
-  #:description
-  "Internal definitions are recommended instead of `let` expressions, to reduce nesting."
-  #:literals (cond)
-  (cond-id:cond clause-before ... clause:let-refactorable-cond-clause clause-after ...)
-  (cond-id clause-before ... clause.refactored clause-after ...))
 
 
 (define-syntax-class if-arm
@@ -297,7 +282,6 @@ tail expression outside `cond` lets you replace `cond` with `when`."
            always-throwing-if-to-when
            and-let-to-cond
            cond-else-cond-to-cond
-           cond-let-to-cond-define
            cond-void-to-when-or-unless
            explicit-cond-else-void
            if-begin-to-cond

default-recommendations/let-replacement/cond-let-replacement-test.rkt

@@ -0,0 +1,44 @@
+#lang resyntax/test
+
+
+require: resyntax/default-recommendations cond-let-replacement
+
+
+header:
+- #lang racket/base
+
+
+test: "cond with nested let refactorable to cond with define"
+------------------------------
+(define (f a c)
+  (cond
+    [a
+     (let ([x "stuff"])
+       x)]
+    [else c]))
+==============================
+(define (f a c)
+  (cond
+    [a
+     (define x "stuff")
+     x]
+    [else c]))
+------------------------------
+
+
+test: "cond with nested let in else clause refactorable to cond with define"
+------------------------------
+(define (f a b)
+  (cond
+    [a b]
+    [else
+     (let ([x "stuff"])
+       x)]))
+==============================
+(define (f a b)
+  (cond
+    [a b]
+    [else
+     (define x "stuff")
+     x]))
+------------------------------

default-recommendations/let-replacement/cond-let-replacement.rkt

@@ -0,0 +1,38 @@
+#lang racket/base
+
+
+(require racket/contract/base)
+
+
+(provide
+ (contract-out
+  [cond-let-replacement refactoring-suite?]))
+
+
+(require resyntax/base
+         resyntax/default-recommendations/let-replacement/private/let-binding
+         syntax/parse)
+
+
+;@----------------------------------------------------------------------------------------------------
+
+
+(define-syntax-class let-refactorable-cond-clause
+  #:attributes (refactored)
+  (pattern [condition:expr leading-body ... let-expr:refactorable-let-expression]
+    #:with refactored
+    #`(~replacement
+       [condition leading-body ... (~@ . (~focus-replacement-on (let-expr.refactored ...)))]
+       #:original #,this-syntax)))
+
+
+(define-refactoring-rule cond-let-to-cond-define
+  #:description
+  "Internal definitions are recommended instead of `let` expressions, to reduce nesting."
+  #:literals (cond)
+  (cond-id:cond clause-before ... clause:let-refactorable-cond-clause clause-after ...)
+  (cond-id clause-before ... clause.refactored clause-after ...))
+
+
+(define-refactoring-suite cond-let-replacement
+  #:rules (cond-let-to-cond-define))

…let-binding-suggestions-comment-test.rkt …let-binding-suggestions-comment-test.rktdefault-recommendations/let-binding-suggestions-comment-test.rkt renamed to default-recommendations/let-replacement/let-binding-suggestions-comment-test.rkt default-recommendations/let-binding-suggestions-comment-test.rkt renamed to default-recommendations/let-replacement/let-binding-suggestions-comment-test.rkt

@@ -1,7 +1,7 @@
 #lang resyntax/test
 
 
-require: resyntax/default-recommendations let-binding-suggestions
+require: resyntax/default-recommendations let-replacement
 
 
 header:

…-suggestions-function-shortcuts-test.rkt …-suggestions-function-shortcuts-test.rktdefault-recommendations/let-binding-suggestions-function-shortcuts-test.rkt renamed to default-recommendations/let-replacement/let-binding-suggestions-function-shortcuts-test.rkt default-recommendations/let-binding-suggestions-function-shortcuts-test.rkt renamed to default-recommendations/let-replacement/let-binding-suggestions-function-shortcuts-test.rkt

@@ -1,7 +1,7 @@
 #lang resyntax/test
 
 
-require: resyntax/default-recommendations let-binding-suggestions
+require: resyntax/default-recommendations let-replacement
 
 
 header:

…let-binding-suggestions-nesting-test.rkt …let-binding-suggestions-nesting-test.rktdefault-recommendations/let-binding-suggestions-nesting-test.rkt renamed to default-recommendations/let-replacement/let-binding-suggestions-nesting-test.rkt default-recommendations/let-binding-suggestions-nesting-test.rkt renamed to default-recommendations/let-replacement/let-binding-suggestions-nesting-test.rkt

@@ -1,7 +1,7 @@
 #lang resyntax/test
 
 
-require: resyntax/default-recommendations let-binding-suggestions
+require: resyntax/default-recommendations let-replacement
 
 
 header:

default-recommendations/let-replacement/let-binding-suggestions-test.rkt

@@ -0,0 +1,43 @@
+#lang resyntax/test
+
+
+require: resyntax/default-recommendations let-binding-suggestions
+
+
+header:
+- #lang racket/base
+test: "named lets which don't refer to the name are refactorable to unnamed lets"
+------------------------------
+(let loop ([x 1]) x)
+==============================
+(let ([x 1]) x)
+------------------------------
+
+
+no-change-test: "named lets which do refer to the name aren't refactorable to unnamed lets"
+------------------------------
+(let loop ([x 1])
+  (if (zero? x)
+      x
+      (loop (sub1 x))))
+------------------------------
+
+
+test: "let-values expressions with an immediate call are refactorable to call-with-values"
+- (let-values ([(x y z) (values 1 2 3)]) (list x y z))
+- (call-with-values (λ () (values 1 2 3)) list)
+
+
+no-change-test:
+"let-values expressions with an immediate call with different order aren't refactorable"
+- (let-values ([(x y z) (values 1 2 3)]) (list z y x))
+test: "redundant let bindings can be removed"
+------------------------------
+(define x 1)
+(let ([x x])
+  (* x 2))
+==============================
+(define x 1)
+(* x 2)
+------------------------------
+

default-recommendations/let-replacement/let-binding-suggestions.rkt

@@ -0,0 +1,55 @@
+#lang racket/base
+
+
+(require racket/contract/base)
+
+
+(provide
+ (contract-out
+  [let-binding-suggestions refactoring-suite?]))
+
+
+(require racket/list
+         racket/set
+         resyntax/base
+         resyntax/default-recommendations/private/syntax-equivalence
+         resyntax/default-recommendations/private/syntax-identifier-sets
+         syntax/parse)
+
+
+;@----------------------------------------------------------------------------------------------------
+
+
+(define-refactoring-rule named-let-to-plain-let
+  #:description
+  "This named `let` loop doesn't actually perform any recursive calls, and can be replaced with an\
+ unnamed `let`."
+  #:literals (let)
+  (let name:id header body ...)
+  #:when (not (set-member? (syntax-free-identifiers #'(body ...)) #'name))
+  (let header body ...))
+
+
+(define-refactoring-rule let-values-then-call-to-call-with-values
+  #:description
+  "This `let-values` expression can be replaced with a simpler, equivalent `call-with-values`\
+ expression."
+  #:literals (let-values)
+  (let-values ([(bound-id:id ...+) expr])
+    (receiver:id arg-id:id ...+))
+  #:when (syntax-free-identifier=? #'(bound-id ...) #'(arg-id ...))
+  (call-with-values (λ () expr) receiver))
+
+
+(define-refactoring-rule delete-redundant-let
+  #:description "This `let` binding does nothing and can be removed."
+  #:literals (let)
+  (let ([left-id:id right-id:id]) body)
+  #:when (equal? (syntax-e (attribute left-id)) (syntax-e (attribute right-id)))
+  body)
+
+
+(define-refactoring-suite let-binding-suggestions
+  #:rules (delete-redundant-let
+           let-values-then-call-to-call-with-values
+           named-let-to-plain-let))