Fix up regression in ruby parser translation

Author: kddnewton

lib/prism/translation/ruby_parser.rb

@@ -881,6 +881,7 @@ def visit_interpolated_x_string_node(node)
         # Visit the interpolated content of the string-like node.
         private def visit_interpolated_parts(parts)
           visited = []
+
           parts.each do |part|
             result = visit(part)
 
@@ -892,6 +893,7 @@ def visit_interpolated_x_string_node(node)
               else
                 visited << result
               end
+              visited << :space
             elsif result[0] == :dstr
               if !visited.empty? && part.parts[0].is_a?(StringNode)
                 # If we are in the middle of an implicitly concatenated string,
@@ -907,8 +909,9 @@ def visit_interpolated_x_string_node(node)
           end
 
           state = :beginning #: :beginning | :string_content | :interpolated_content
+          results = []
 
-          visited.each_with_object([]) do |result, results|
+          visited.each_with_index do |result, index|
             case state
             when :beginning
               if result.is_a?(String)
@@ -923,7 +926,9 @@ def visit_interpolated_x_string_node(node)
                 state = :interpolated_content
               end
             when :string_content
-              if result.is_a?(String)
+              if result == :space
+                # continue
+              elsif result.is_a?(String)
                 results[0] << result
               elsif result.is_a?(Array) && result[0] == :str
                 results[0] << result[1]
@@ -932,14 +937,18 @@ def visit_interpolated_x_string_node(node)
                 state = :interpolated_content
               end
             when :interpolated_content
-              if result.is_a?(Array) && result[0] == :str && results[-1][0] == :str && (results[-1].line_max == result.line)
+              if result == :space
+                # continue
+              elsif visited[index - 1] != :space && result.is_a?(Array) && result[0] == :str && results[-1][0] == :str && (results[-1].line_max == result.line)
                 results[-1][1] << result[1]
                 results[-1].line_max = result.line_max
               else
                 results << result
               end
             end
           end
+
+          results
         end
 
         # -> { it }

test/prism/fixtures/strings.txt

@@ -103,3 +103,5 @@
 %^#$^#
 
 %@#@#
+
+"#{"#{B} C"} D"