[Sass] Make sure Sass errors during #cssize are properly bubbled up.

lib/sass/tree/import_node.rb

@@ -14,6 +14,15 @@ module Sass
 
       protected
 
+      # @see \{Node#_cssize}
+      def _cssize(*args)
+        super
+      rescue Sass::SyntaxError => e
+        e.modify_backtrace(:filename => children.first.filename)
+        e.add_backtrace(:filename => @filename, :line => @line)
+        raise e
+      end
+
       # Computes the CSS for the imported file.
       #
       # @param args [Array] Ignored

test/sass/engine_test.rb

@@ -189,7 +189,7 @@ SASS
   end
 
   def test_imported_exception
-    [1, 2, 3].each do |i|
+    [1, 2, 3, 4].each do |i|
       begin
         Sass::Engine.new("@import bork#{i}", :load_paths => [File.dirname(__FILE__) + '/templates/']).render
       rescue Sass::SyntaxError => err
@@ -211,7 +211,7 @@ SASS
   end
 
   def test_double_imported_exception
-    [1, 2, 3].each do |i|
+    [1, 2, 3, 4].each do |i|
       begin
         Sass::Engine.new("@import nested_bork#{i}", :load_paths => [File.dirname(__FILE__) + '/templates/']).render
       rescue Sass::SyntaxError => err

test/sass/templates/bork4.sass

@@ -0,0 +1,2 @@
+
+bork: blah

test/sass/templates/nested_bork4.sass

@@ -0,0 +1,2 @@
+
+@import bork4