[GR-20446] Update method missing handling to allow method_missing to accept one argument

PullRequest: truffleruby/3288

Author: bjfish

spec/ruby/core/kernel/method_spec.rb

@@ -34,4 +34,28 @@
     m.should be_an_instance_of(Method)
     m.call(1, 2, 3).should == "Done handled_privately([1, 2, 3])"
   end
+
+  it "can call a #method_missing accepting zero or one arguments" do
+    cls = Class.new do
+      def respond_to_missing?(name, *)
+        name == :foo or super
+      end
+      def method_missing
+        :no_args
+      end
+    end
+    m = cls.new.method(:foo)
+    -> { m.call }.should raise_error(ArgumentError)
+
+    cls = Class.new do
+      def respond_to_missing?(name, *)
+        name == :bar or super
+      end
+      def method_missing(m)
+        m
+      end
+    end
+    m = cls.new.method(:bar)
+    m.call.should == :bar
+  end
 end

src/main/java/org/truffleruby/language/methods/SharedMethodInfo.java

@@ -9,8 +9,6 @@
  */
 package org.truffleruby.language.methods;
 
-import java.util.Arrays;
-
 import org.truffleruby.RubyLanguage;
 import org.truffleruby.core.klass.RubyClass;
 import org.truffleruby.core.module.RubyModule;
@@ -19,7 +17,6 @@
 import org.truffleruby.language.RubyGuards;
 import org.truffleruby.language.backtrace.BacktraceFormatter;
 import org.truffleruby.parser.ArgumentDescriptor;
-import org.truffleruby.parser.ArgumentType;
 
 import com.oracle.truffle.api.source.SourceSection;
 
@@ -76,10 +73,6 @@ public SharedMethodInfo forDefineMethod(RubyModule declaringModule, String metho
     }
 
     public SharedMethodInfo convertMethodMissingToMethod(RubyModule declaringModule, String methodName) {
-        final ArgumentDescriptor[] oldArgs = getArgumentDescriptors();
-        final ArgumentDescriptor[] newArgs = Arrays.copyOfRange(oldArgs, 1, oldArgs.length);
-        newArgs[0] = new ArgumentDescriptor(ArgumentType.anonrest);
-
         return new SharedMethodInfo(
                 sourceSection,
                 staticLexicalScope,
@@ -88,7 +81,7 @@ public SharedMethodInfo convertMethodMissingToMethod(RubyModule declaringModule,
                 blockDepth,
                 moduleAndMethodName(declaringModule, methodName),
                 notes,
-                newArgs);
+                ArgumentDescriptor.ANY);
     }
 
     public SharedMethodInfo withArity(Arity newArity) {

src/main/java/org/truffleruby/parser/ArgumentDescriptor.java

@@ -34,6 +34,7 @@ public final class ArgumentDescriptor {
     /** The name of the argument */
     public final String name;
 
+    public static final ArgumentDescriptor[] ANY = { new ArgumentDescriptor(ArgumentType.anonrest) };
     public static final ArgumentDescriptor[] AT_LEAST_ONE = {
             new ArgumentDescriptor(ArgumentType.anonreq),
             new ArgumentDescriptor(ArgumentType.anonrest) };