[Fix #6300] Fix a false positive for Layout/EmptyLineAfterGuardClause

Fixes #6300.

This PR fixes a false positive for `Layout/EmptyLineAfterGuardClause`
when guard clause including heredoc.

CHANGELOG.md

@@ -5,6 +5,7 @@
 ### Bug fixes
 
 * [#6296](https://github.com/rubocop-hq/rubocop/issues/6296): Fix an auto-correct error for `Style/For` when setting `EnforcedStyle: each` and `for` dose not have `do` or semicolon. ([@autopp][])
+* [#6300](https://github.com/rubocop-hq/rubocop/pull/6300): Fix a false positive for `Layout/EmptyLineAfterGuardClause` when guard clause including heredoc. ([@koic][])
 
 ## 0.59.1 (2018-09-15)
 

lib/rubocop/cop/layout/empty_line_after_guard_clause.rb

@@ -44,22 +44,16 @@ class EmptyLineAfterGuardClause < Cop
         def on_if(node)
           return if correct_style?(node)
 
-          if last_argument_is_heredoc?(node)
+          if node.modifier_form? && last_argument_is_heredoc?(node)
             heredoc_node = last_argument(node)
 
-            heredoc_body = heredoc_node.loc.heredoc_body
-            num_of_heredoc_lines =
-              heredoc_body.last_line - heredoc_body.first_line
-
-            line = node.last_line + num_of_heredoc_lines + END_OF_HEREDOC_LINE
-
-            return if next_line_empty?(line)
+            return if next_line_empty?(heredoc_line(node, heredoc_node))
 
             add_offense(heredoc_node, location: :heredoc_end)
           else
             return if next_line_empty?(node.last_line)
 
-            add_offense(node)
+            add_offense(node, location: offense_location(node))
           end
         end
 
@@ -126,6 +120,22 @@ def last_argument_is_heredoc?(node)
         def last_argument(node)
           node.if_branch.children.last
         end
+
+        def heredoc_line(node, heredoc_node)
+          heredoc_body = heredoc_node.loc.heredoc_body
+          num_of_heredoc_lines =
+            heredoc_body.last_line - heredoc_body.first_line
+
+          node.last_line + num_of_heredoc_lines + END_OF_HEREDOC_LINE
+        end
+
+        def offense_location(node)
+          if node.loc && node.loc.end
+            :end
+          else
+            :expression
+          end
+        end
       end
     end
   end

spec/rubocop/cop/layout/empty_line_after_guard_clause_spec.rb

@@ -106,6 +106,36 @@ def foo
     RUBY
   end
 
+  it 'registers an offense for guard clause followed by empty line' \
+     'when guard clause including heredoc' do
+    expect_no_offenses(<<-RUBY.strip_indent)
+      def method
+        if truthy
+          raise <<-MSG
+            This is an error.
+          MSG
+        end
+
+        value
+      end
+    RUBY
+  end
+
+  it 'registers an offense for guard clause not followed by empty line' \
+     'when guard clause including heredoc' do
+    expect_offense(<<-RUBY.strip_indent)
+      def method
+        if truthy
+          raise <<-MSG
+            This is an error.
+          MSG
+        end
+        ^^^ Add empty line after guard clause.
+        value
+      end
+    RUBY
+  end
+
   it 'does not register offense for guard clause followed by end' do
     expect_no_offenses(<<-RUBY.strip_indent)
       def foo