Revert "[Haml] Support concatenating multiple CSS-syntax ids using _."

This reverts commit 5aa2cd6992.

Conflicts:

	doc-src/HAML_CHANGELOG.md

doc-src/HAML_CHANGELOG.md

@@ -21,12 +21,6 @@
   but it shouldn't have too much effect and the optimizations
   will hopefully be re-enabled in version 2.4.
 
-* Allow multiple ids to be used on the same element.
-  They will be concatenated together with an underscore.
-  For example, `%p#foo#bar` will become `<p id="foo_bar">`.
-  This is consistent with the behavior of multiple ids
-  when one is specified as a standard attribute.
-
 * Don't crash if the plugin skeleton is installed and `rake gems:install` is run.
 
 ## [2.2.10](http://github.com/nex3/haml/commit/2.2.10)

lib/haml/precompiler.rb

@@ -479,13 +479,7 @@ END
             attributes['class'] = ""
           end
           attributes['class'] += property
-        when '#'
-          if attributes['id']
-            attributes['id'] += "_"
-          else
-            attributes['id'] = ""
-          end
-          attributes['id'] += property
+        when '#'; attributes['id'] = property
         end
       end
       attributes

test/haml/engine_test.rb

@@ -278,18 +278,6 @@ RESULT
 SOURCE
   end
 
-  def test_multiple_ids
-    assert_equal("<p id='bc_ab'></p>\n", render("%p#bc#ab"))
-    assert_equal("<p id='ab_bc'></p>\n", render("%p#ab#bc"))
-    assert_equal("<p id='ab'></p>\n", render("%p(id='bc' id='ab')"))
-    assert_equal("<p id='bc'></p>\n", render("%p(id='ab' id='bc')"))
-    assert_equal("<p id='bc_ab'></p>\n", render("%p#bc(id='ab')"))
-    assert_equal("<p id='ab_bc'></p>\n", render("%p#ab(id='bc')"))
-    assert_equal("<p id='bc_ab'></p>\n", render("%p#bc{:id => 'ab'}"))
-    assert_equal("<p id='ab_bc'></p>\n", render("%p#ab{:id => 'bc'}"))
-    assert_equal("<p id='ab_bc_cd'></p>\n", render("%p#ab{:id => 'bc'}(id='cd')"))
-  end
-
   # Regression tests
 
   def test_whitespace_nuke_with_both_newlines

test/haml/results/tag_parsing.xhtml

@@ -12,7 +12,7 @@
   <foo2u>11</foo2u>
 </div>
 <div class='classes'>
-  <p class='foo bar' id='baz_boom'></p>
+  <p class='foo bar' id='boom'></p>
   <div class='fooBar'>a</div>
   <div class='foo-bar'>b</div>
   <div class='foo_bar'>c</div>