Incorrectly reporting shadowingOuterLocalVar within macro included

closes #129

spec/ameba/ast/scope_spec.cr

@@ -84,4 +84,20 @@ module Ameba::AST
       scope.block?.should be_false
     end
   end
+
+  describe "#macro?" do
+    it "returns true if Crystal::Macro" do
+      nodes = as_nodes %(
+        macro included
+        end
+      )
+      scope = Scope.new nodes.macro_nodes.first
+      scope.macro?.should be_true
+    end
+
+    it "returns false otherwise" do
+      scope = Scope.new as_node "a = 1"
+      scope.macro?.should be_false
+    end
+  end
 end

spec/ameba/rule/lint/shadowing_local_outer_var_spec.cr

@@ -174,5 +174,24 @@ module Ameba::Rule::Lint
       issue.end_location.should be_nil
       issue.message.should eq "Shadowing outer local variable `foo`"
     end
+
+    context "macro" do
+      it "does not report shadowed vars A" do
+        source = Source.new %(
+          macro included
+            def foo
+              {% for ivar in instance_vars %}
+                {% ann = ivar.annotation(Name) %}
+              {% end %}
+            end
+
+            def bar
+              {% instance_vars.reject { |ivar| ivar } %}
+            end
+          end
+        )
+        subject.catch(source).should be_valid
+      end
+    end
   end
 end

spec/spec_helper.cr

@@ -139,6 +139,7 @@ module Ameba
       Crystal::OpAssign,
       Crystal::MultiAssign,
       Crystal::Block,
+      Crystal::Macro,
       Crystal::Def,
       Crystal::If,
       Crystal::While,

src/ameba/ast/scope.cr

@@ -94,6 +94,11 @@ module Ameba::AST
       node.is_a?(Crystal::Block) || node.is_a?(Crystal::ProcLiteral)
     end
 
+    # Returns true if currency scope represents a macro.
+    def macro?
+      node.is_a?(Crystal::Macro)
+    end
+
     # Returns true instance variable assinged in this scope.
     def assigns_ivar?(name)
       arguments.find { |arg| arg.name == name } &&

src/ameba/rule/lint/shadowing_local_outer_var.cr

@@ -53,9 +53,11 @@ module Ameba::Rule::Lint
 
     private def find_shadowing(source, scope)
       scope.arguments.each do |arg|
-        next if arg.ignored?
         outer_scope = scope.outer_scope
-        if outer_scope && outer_scope.find_variable(arg.name) && !outer_scope.assigns_ivar?(arg.name)
+
+        next if arg.ignored? || outer_scope.nil?
+
+        if !outer_scope.macro? && outer_scope.find_variable(arg.name) && !outer_scope.assigns_ivar?(arg.name)
           issue_for arg.node, MSG % arg.name
         end
       end