MethodNames: correct reported location/end_location

spec/ameba/rule/style/method_names_spec.cr

@@ -40,14 +40,14 @@ module Ameba
 
     it "reports rule, pos and message" do
       s = Source.new %(
-        def bad_Name
+        def bad_Name(a)
         end
       ), "source.cr"
       subject.catch(s).should_not be_valid
       issue = s.issues.first
       issue.rule.should_not be_nil
-      issue.location.to_s.should eq "source.cr:1:1"
+      issue.location.to_s.should eq "source.cr:1:5"
-      issue.end_location.to_s.should eq "source.cr:2:3"
+      issue.end_location.to_s.should eq "source.cr:1:12"
       issue.message.should eq(
         "Method name should be underscore-cased: bad_name, not bad_Name"
       )

src/ameba/reportable.cr

@@ -26,6 +26,13 @@ module Ameba
       add_issue rule, location, nil, message, **args
     end
 
+    # Adds a new issue for *location* and *end_location* defined by line and column numbers.
+    def add_issue(rule, location : Tuple(Int32, Int32), end_location : Tuple(Int32, Int32), message, **args)
+      location = Crystal::Location.new path, *location
+      end_location = Crystal::Location.new path, *end_location
+      add_issue rule, location, end_location, message, **args
+    end
+
     # Returns true if the list of not disabled issues is empty, false otherwise.
     def valid?
       issues.reject(&.disabled?).empty?

src/ameba/rule/style/method_names.cr

@@ -52,7 +52,16 @@ module Ameba::Rule::Style
     def test(source, node : Crystal::Def)
       return if (expected = node.name.underscore) == node.name
 
-      issue_for node, MSG % {expected, node.name}
+      line_number = node.location.try &.line_number
+      column_number = node.name_column_number
+
+      return unless line_number
+
+      issue_for(
+        {line_number, column_number},
+        {line_number, column_number + node.name.size - 1},
+        MSG % {expected, node.name}
+      )
     end
   end
 end