Deprecate the splat operators in macro expressions (crystal-lang#13939)

Co-authored-by: Johannes Müller <[email protected]>

src/compiler/crystal/interpreter/compiler.cr

@@ -3145,11 +3145,7 @@ class Crystal::Repl::Compiler < Crystal::Visitor
     {% operands = instruction[:operands] || [] of Nil %}
 
     def {{name.id}}(
-      {% if operands.empty? %}
-        *, node : ASTNode?
-      {% else %}
-        {{*operands}}, *, node : ASTNode?
-      {% end %}
+      {{operands.splat(", ")}}*, node : ASTNode?
     ) : Nil
       node = @node_override || node
       @instructions.nodes[instructions_index] = node if node

src/compiler/crystal/macros/interpreter.cr

@@ -511,12 +511,14 @@ module Crystal
     end
 
     def visit(node : Splat)
+      warnings.add_warning(node, "Deprecated use of splat operator. Use `#splat` instead")
       node.exp.accept self
       @last = @last.interpret("splat", [] of ASTNode, nil, nil, self, node.location)
       false
     end
 
     def visit(node : DoubleSplat)
+      warnings.add_warning(node, "Deprecated use of double splat operator. Use `#double_splat` instead")
       node.exp.accept self
       @last = @last.interpret("double_splat", [] of ASTNode, nil, nil, self, node.location)
       false

src/macros.cr

@@ -82,49 +82,49 @@ macro record(__name name, *properties, **kwargs)
     {% end %}
 
     def initialize({{
-                     *properties.map do |field|
+                     properties.map do |field|
                        "@#{field.id}".id
-                     end
+                     end.splat
                    }})
     end
 
     {{yield}}
 
     def copy_with({{
-                    *properties.map do |property|
+                    properties.map do |property|
                       if property.is_a?(Assign)
                         "#{property.target.id} _#{property.target.id} = @#{property.target.id}".id
                       elsif property.is_a?(TypeDeclaration)
                         "#{property.var.id} _#{property.var.id} = @#{property.var.id}".id
                       else
                         "#{property.id} _#{property.id} = @#{property.id}".id
                       end
-                    end
+                    end.splat
                   }})
       self.class.new({{
-                       *properties.map do |property|
+                       properties.map do |property|
                          if property.is_a?(Assign)
                            "_#{property.target.id}".id
                          elsif property.is_a?(TypeDeclaration)
                            "_#{property.var.id}".id
                          else
                            "_#{property.id}".id
                          end
-                       end
+                       end.splat
                      }})
     end
 
     def clone
       self.class.new({{
-                       *properties.map do |property|
+                       properties.map do |property|
                          if property.is_a?(Assign)
                            "@#{property.target.id}.clone".id
                          elsif property.is_a?(TypeDeclaration)
                            "@#{property.var.id}.clone".id
                          else
                            "@#{property.id}.clone".id
                          end
-                       end
+                       end.splat
                      }})
     end
   end
@@ -150,7 +150,7 @@ macro pp!(*exps)
     ::print %prefix
     ::pp({{exp}})
   {% else %}
-    %names = { {{*exps.map(&.stringify)}} }
+    %names = { {{exps.map(&.stringify).splat}} }
     %max_size = %names.max_of &.size
     {
       {% for exp, i in exps %}
@@ -184,7 +184,7 @@ macro p!(*exps)
     ::print %prefix
     ::p({{exp}})
   {% else %}
-    %names = { {{*exps.map(&.stringify)}} }
+    %names = { {{exps.map(&.stringify).splat}} }
     %max_size = %names.max_of &.size
     {
       {% for exp, i in exps %}

src/object.cr

@@ -1086,7 +1086,7 @@ class Object
     # end
     # ```
     macro {{macro_prefix}}property!(*names)
-      {{macro_prefix}}getter! \{{*names}}
+      {{macro_prefix}}getter! \{{names.splat}}
 
       \{% for name in names %}
         \{% if name.is_a?(TypeDeclaration) %}
@@ -1377,8 +1377,8 @@ class Object
   # end
   # ```
   macro def_equals_and_hash(*fields)
-    def_equals {{*fields}}
-    def_hash {{*fields}}
+    def_equals {{fields.splat}}
+    def_hash {{fields.splat}}
   end
 
   # Forwards missing methods to *delegate*.

src/regex.cr

@@ -403,7 +403,7 @@ class Regex
       str.each_byte do |byte|
         {% begin %}
           case byte.unsafe_chr
-          when {{*SPECIAL_CHARACTERS}}
+          when {{SPECIAL_CHARACTERS.splat}}
             result << '\\'
             result.write_byte byte
           else

src/slice.cr

@@ -37,7 +37,7 @@ struct Slice(T)
     {% if @type.name != "Slice(T)" && T < Number %}
       {{T}}.slice({{args.splat(", ")}}read_only: {{read_only}})
     {% else %}
-      %ptr = Pointer(typeof({{*args}})).malloc({{args.size}})
+      %ptr = Pointer(typeof({{args.splat}})).malloc({{args.size}})
       {% for arg, i in args %}
         %ptr[{{i}}] = {{arg}}
       {% end %}

src/static_array.cr

@@ -50,7 +50,7 @@ struct StaticArray(T, N)
   # * `Number.static_array` is a convenient alternative for designating a
   #   specific numerical item type.
   macro [](*args)
-    %array = uninitialized StaticArray(typeof({{*args}}), {{args.size}})
+    %array = uninitialized StaticArray(typeof({{args.splat}}), {{args.size}})
     {% for arg, i in args %}
       %array.to_unsafe[{{i}}] = {{arg}}
     {% end %}

src/syscall/aarch64-linux.cr

@@ -335,7 +335,7 @@ module Syscall
 
   macro def_syscall(name, return_type, *args)
     @[AlwaysInline]
-    def self.{{name.id}}({{*args}}) : {{return_type}}
+    def self.{{name.id}}({{args.splat}}) : {{return_type}}
       ret = uninitialized {{return_type}}
 
       {% if args.size == 0 %}

src/syscall/arm-linux.cr

@@ -410,7 +410,7 @@ module Syscall
 
   macro def_syscall(name, return_type, *args)
     @[AlwaysInline]
-    def self.{{name.id}}({{*args}}) : {{return_type}}
+    def self.{{name.id}}({{args.splat}}) : {{return_type}}
       ret = uninitialized {{return_type}}
 
       {% if args.size == 0 %}

src/syscall/i386-linux.cr

@@ -446,7 +446,7 @@ module Syscall
 
   macro def_syscall(name, return_type, *args)
     @[AlwaysInline]
-    def self.{{name.id}}({{*args}}) : {{return_type}}
+    def self.{{name.id}}({{args.splat}}) : {{return_type}}
       ret = uninitialized {{return_type}}
 
       {% if args.size == 0 %}

src/syscall/x86_64-linux.cr

@@ -369,7 +369,7 @@ module Syscall
 
   macro def_syscall(name, return_type, *args)
     @[AlwaysInline]
-    def self.{{name.id}}({{*args}}) : {{return_type}}
+    def self.{{name.id}}({{args.splat}}) : {{return_type}}
       ret = uninitialized {{return_type}}
 
       {% if args.size == 0 %}

src/xml/builder.cr

@@ -283,7 +283,7 @@ class XML::Builder
   end
 
   private macro call(name, *args)
-    ret = LibXML.xmlTextWriter{{name}}(@writer, {{*args}})
+    ret = LibXML.xmlTextWriter{{name}}(@writer, {{args.splat}})
     check ret, {{@def.name.stringify}}
   end
 

src/yaml/builder.cr

@@ -199,7 +199,7 @@ class YAML::Builder
   end
 
   private macro emit(event_name, *args)
-    LibYAML.yaml_{{event_name}}_event_initialize(pointerof(@event), {{*args}})
+    LibYAML.yaml_{{event_name}}_event_initialize(pointerof(@event), {{args.splat}})
     yaml_emit({{event_name.stringify}})
   end