Prevent opening ERB line from being a rubocop violation

lib/erb_lint/linters/rubocop.rb

@@ -79,10 +79,21 @@ def activate_team(processed_source, source, offset, code_node, team)
             .to_source_range(rubocop_offense.location)
             .offset(offset)
 
+          next if offense_removes_erb_tag(rubocop_offense, processed_source)
+
           add_offense(rubocop_offense, offense_range, correction, offset, code_node.loc.range)
         end
       end
 
+      def offense_removes_erb_tag(rubocop_offense, processed_source)
+        range = rubocop_offense.location
+
+        removed_lines = processed_source.to_source_range(range).source
+
+        erb_tag_pattern = /\A<%=?\z/
+        removed_lines.match?(erb_tag_pattern)
+      end
+
       def tempfile_from(filename, content)
         Tempfile.create(File.basename(filename), Dir.pwd) do |tempfile|
           tempfile.write(content)

spec/erb_lint/linters/rubocop_spec.rb

@@ -271,6 +271,49 @@
     end
   end
 
+  context "code includes an opening erb tag followed by ruby on subsequent line" do
+    let(:linter_config) do
+      described_class.config_schema.new(
+        only: only_cops,
+        rubocop_config: {
+          AllCops: {
+            TargetRubyVersion: "2.5",
+          },
+        }
+        )
+    end
+
+    let(:only_cops) { ["Layout/TrailingWhitespace"] }
+
+    let(:file) { <<~FILE }
+      <%
+        some_ruby_code
+      %>
+    FILE
+
+    it "does not consider the opening erb line to be a whitespace violation" do
+      expect(subject).to(eq([]))
+    end
+
+    context "when the opening erb line includes other violations" do
+      let(:only_cops) { ["Layout/TrailingWhitespace", "Layout/EmptyComment"] }
+      let(:file) { <<~FILE }
+        <% #
+          some_ruby_code
+        %>
+      FILE
+
+      it "adds offenses" do
+        expect(subject.size).to(eq(1))
+        expect(subject[0].source_range.begin_pos).to(eq(3))
+        expect(subject[0].source_range.end_pos).to(eq(4))
+        expect(subject[0].source_range.source).to(eq("#"))
+        expect(subject[0].line_range).to(eq(1..1))
+        expect(subject[0].message).to(eq("Layout/EmptyComment: Source code comment is empty."))
+      end
+    end
+  end
+
   context "code is aligned to the column matching start of ruby code" do
     let(:linter_config) do
       described_class.config_schema.new(