Implement string concat for ripper translation

Author: kddnewton

lib/prism/translation/ripper.rb

@@ -1696,11 +1696,19 @@ def visit_interpolated_regular_expression_node(node)
       # "foo #{bar}"
       # ^^^^^^^^^^^^
       def visit_interpolated_string_node(node)
-        if node.opening.start_with?("<<~")
+        if node.opening&.start_with?("<<~")
           heredoc = visit_string_heredoc_node(node.parts)
 
           bounds(node.location)
           on_string_literal(heredoc)
+        elsif !node.heredoc? && node.parts.length > 1 && node.parts.any? { |part| (part.is_a?(StringNode) || part.is_a?(InterpolatedStringNode)) && !part.opening_loc.nil? }
+          first, *rest = node.parts
+          rest.inject(visit(first)) do |content, part|
+            concat = visit(part)
+
+            bounds(part.location)
+            on_string_concat(content, concat)
+          end
         else
           bounds(node.parts.first.location)
           parts =

test/prism/ripper_test.rb

@@ -61,14 +61,11 @@ class RipperTest < TestCase
       seattlerb/lambda_do_vs_brace.txt
       seattlerb/parse_line_dstr_escaped_newline.txt
       seattlerb/parse_line_dstr_soft_newline.txt
-      seattlerb/parse_line_evstr_after_break.txt
       seattlerb/parse_pattern_051.txt
       seattlerb/parse_pattern_058.txt
       seattlerb/stabby_block_iter_call.txt
       seattlerb/stabby_block_iter_call_no_target_with_arg.txt
-      seattlerb/str_lit_concat_bad_encodings.txt
       spanning_heredoc.txt
-      strings.txt
       tilde_heredocs.txt
       unparser/corpus/literal/assignment.txt
       unparser/corpus/literal/block.txt
@@ -96,10 +93,8 @@ class RipperTest < TestCase
       whitequark/parser_drops_truncated_parts_of_squiggly_heredoc.txt
       whitequark/parser_slash_slash_n_escaping_in_literals.txt
       whitequark/ruby_bug_11107.txt
-      whitequark/ruby_bug_11990.txt
       whitequark/send_block_chain_cmd.txt
       whitequark/slash_newline_in_heredocs.txt
-      whitequark/string_concat.txt
     ]
 
     relatives.each do |relative|