Compiler: let method_missing work with named arguments. Fixes #3654

Ary Borenszweig · Ary Borenszweig · commit 8295d8ccae7a · 2016-12-08T11:25:13.000-03:00
diff --git a/spec/compiler/codegen/method_missing_spec.cr b/spec/compiler/codegen/method_missing_spec.cr
@@ -381,4 +381,31 @@ describe "Code gen: method_missing" do
       Foo.new.bar
       )).to_string.should eq("bar")
   end
+
+  it "works with named arguments, using names (#3654)" do
+    run(%(
+      class A
+        macro method_missing(call)
+          x + y
+        end
+      end
+
+      a = A.new
+      a.b(x: 1, y: 2)
+      )).to_i.should eq(3)
+  end
+
+  it "works with named arguments, named args in call (#3654)" do
+    run(%(
+      class A
+        macro method_missing(call)
+          {{call.named_args[0].name}} +
+            {{call.named_args[1].name}}
+        end
+      end
+
+      a = A.new
+      a.b(x: 1, y: 2)
+      )).to_i.should eq(3)
+  end
 end
diff --git a/src/compiler/crystal/semantic/method_missing.cr b/src/compiler/crystal/semantic/method_missing.cr
@@ -38,12 +38,21 @@ module Crystal
     def define_method_from_method_missing(method_missing, signature, original_call)
       name_node = StringLiteral.new(signature.name)
       args_nodes = [] of ASTNode
+      named_args_nodes = nil
       args_nodes_names = Set(String).new
       signature.arg_types.each_index do |index|
         arg_node_name = "_arg#{index}"
         args_nodes << MacroId.new(arg_node_name)
         args_nodes_names << arg_node_name
       end
+      if named_args = signature.named_args
+        args_nodes_names << ""
+        named_args.try &.each do |named_arg|
+          named_args_nodes ||= [] of NamedArgument
+          named_args_nodes << NamedArgument.new(named_arg.name, MacroId.new(named_arg.name))
+          args_nodes_names << named_arg.name
+        end
+      end
       args_node = ArrayLiteral.new(args_nodes)
       if block = signature.block
         block_vars = block.args.map_with_index do |var, index|
@@ -57,8 +66,12 @@ module Crystal
       end
 
       a_def = Def.new(signature.name, args_nodes_names.map { |name| Arg.new(name) })
+      a_def.splat_index = signature.arg_types.size if signature.named_args
 
-      call = Call.new(nil, signature.name, args: args_nodes, block: block_node.is_a?(Block) ? block_node : nil)
+      call = Call.new(nil, signature.name,
+        args: args_nodes,
+        named_args: named_args_nodes,
+        block: block_node.is_a?(Block) ? block_node : nil)
       fake_call = Call.new(nil, "method_missing", [call] of ASTNode)
 
       expanded_macro = program.expand_macro method_missing, fake_call, self, self
