Fix {Proc,Method,UnboundMethod}#parameters to return proper parameter names

Author: andrykonchin

CHANGELOG.md

@@ -54,6 +54,7 @@ Compatibility:
 * Limit maximum encoding set size by 256 (#3039, @thomasmarshall, @goyox86).
 * Remove deprecated methods `Dir.exists?`, `File.exists?`, and `Kernel#=~` (#3039, @patricklinpl, @nirvdrum).
 * Remove deprecated `FileTest.exists?` method (#3039, @andrykonchin).
+* Fix {Method,Proc}#parameters and return `*`, `**` and `&` names for anonymous parameters (@andrykonchin).
 
 Performance:
 

spec/ruby/core/method/parameters_spec.rb

@@ -22,6 +22,8 @@ def one_splat_one_block(*args, &block)
       local_is_not_parameter = {}
     end
 
+    def forward_parameters(...) end
+
     def underscore_parameters(_, _, _ = 1, *_, _:, _: 2, **_, &_); end
 
     define_method(:one_optional_defined_method) {|x = 1|}
@@ -267,6 +269,20 @@ def object.foo(&)
     end
   end
 
+  ruby_version_is ""..."3.1" do
+    it "returns [:rest, :*], [:block, :&] for forward parameters operator" do
+      m = MethodSpecs::Methods.new
+      m.method(:forward_parameters).parameters.should == [[:rest, :*], [:block, :&]]
+    end
+  end
+
+  ruby_version_is "3.1" do
+    it "returns [:rest, :*], [:keyrest, :**], [:block, :&] for forward parameters operator" do
+      m = MethodSpecs::Methods.new
+      m.method(:forward_parameters).parameters.should == [[:rest, :*], [:keyrest, :**], [:block, :&]]
+    end
+  end
+
   it "returns the args and block for a splat and block argument" do
     m = MethodSpecs::Methods.new
     m.method(:one_splat_one_block).parameters.should == [[:rest, :args], [:block, :block]]

spec/ruby/core/proc/parameters_spec.rb

@@ -170,4 +170,8 @@
       [:block, :_]
     ]
   end
+
+  it "returns :nokey for **nil parameter" do
+    proc { |**nil| }.parameters.should == [[:nokey]]
+  end
 end

spec/tags/core/method/parameters_tags.txt

@@ -15,11 +15,15 @@
 import org.truffleruby.RubyLanguage;
 import org.truffleruby.core.array.ArrayHelpers;
 import org.truffleruby.core.array.RubyArray;
+import org.truffleruby.core.symbol.RubySymbol;
 import org.truffleruby.parser.ArgumentDescriptor;
 import org.truffleruby.parser.ArgumentType;
 
 import com.oracle.truffle.api.CompilerDirectives.TruffleBoundary;
-import org.truffleruby.parser.TranslatorEnvironment;
+
+import static org.truffleruby.parser.TranslatorEnvironment.FORWARDED_BLOCK_NAME;
+import static org.truffleruby.parser.TranslatorEnvironment.FORWARDED_KEYWORD_REST_NAME;
+import static org.truffleruby.parser.TranslatorEnvironment.FORWARDED_REST_NAME;
 
 public final class ArgumentDescriptorUtils {
 
@@ -44,16 +48,22 @@ private static RubyArray toArray(RubyLanguage language, RubyContext context, Arg
 
     private static RubyArray toArray(RubyLanguage language, RubyContext context, ArgumentType argType, String name) {
         final Object[] store;
+        final RubySymbol typeSymbol = language.getSymbol(argType.symbolicName);
 
-        if (argType.anonymous || name == null) {
-            store = new Object[]{ language.getSymbol(argType.symbolicName) };
+        if (argType == ArgumentType.anonrest) {
+            store = new Object[]{ typeSymbol, language.getSymbol("*") };
+        } else if (argType == ArgumentType.anonkeyrest) {
+            store = new Object[]{ typeSymbol, language.getSymbol("**") };
+        } else if (argType == ArgumentType.rest && name.equals(FORWARDED_REST_NAME)) {
+            store = new Object[]{ typeSymbol, language.getSymbol("*") };
+        } else if (argType == ArgumentType.keyrest && name.equals(FORWARDED_KEYWORD_REST_NAME)) {
+            store = new Object[]{ typeSymbol, language.getSymbol("**") };
+        } else if (argType == ArgumentType.block && name.equals(FORWARDED_BLOCK_NAME)) {
+            store = new Object[]{ typeSymbol, language.getSymbol("&") };
+        } else if (argType.anonymous || name == null) {
+            store = new Object[]{ typeSymbol };
         } else {
-            // make sure to normalize parameter names to "_" if they start with "_$"
-            if (name.startsWith(TranslatorEnvironment.UNDERSCORE_PREFIX)) {
-                name = "_";
-            }
-
-            store = new Object[]{ language.getSymbol(argType.symbolicName), language.getSymbol(name) };
+            store = new Object[]{ typeSymbol, language.getSymbol(name) };
         }
 
         return ArrayHelpers.createArray(context, language, store);

spec/tags/core/proc/parameters_tags.txt

@@ -39,6 +39,7 @@ public enum ArgumentType {
     anonopt("opt", true),
     anonrest("rest", true),
     anonkeyrest("keyrest", true),
+    anonblock("block", true),
     nokey("nokey", true); // **nil
 
     ArgumentType(String symbolicName, boolean anonymous) {

src/main/java/org/truffleruby/language/arguments/ArgumentDescriptorUtils.java

@@ -57,11 +57,11 @@ public final class TranslatorEnvironment {
     static final String DEFAULT_KEYWORD_REST_NAME = Layouts.TEMP_PREFIX + "kwrest";
 
     /** local variable name for * parameter caused by desugaring ... parameter (forward-everything) */
-    static final String FORWARDED_REST_NAME = Layouts.TEMP_PREFIX + "forward_rest";
+    public static final String FORWARDED_REST_NAME = Layouts.TEMP_PREFIX + "forward_rest";
     /** local variable name for ** parameter caused by desugaring ... parameter (forward-everything) */
-    static final String FORWARDED_KEYWORD_REST_NAME = Layouts.TEMP_PREFIX + "forward_kwrest";
+    public static final String FORWARDED_KEYWORD_REST_NAME = Layouts.TEMP_PREFIX + "forward_kwrest";
     /** local variable name for & parameter caused by desugaring ... parameter (forward-everything) */
-    static final String FORWARDED_BLOCK_NAME = Layouts.TEMP_PREFIX + "forward_block";
+    public static final String FORWARDED_BLOCK_NAME = Layouts.TEMP_PREFIX + "forward_block";
 
     /** A prefix for duplicated '_' local variables to build unique names */
     public static final String UNDERSCORE_PREFIX = "_$";