[WIP] add error_squiggle gem

```
$ ./local/bin/ruby -e '1.time {}'
-e:1:in `<main>': undefined method `time' for 1:Integer (NoMethodError)

1.time {}
 ^^^^^
Did you mean?  times
```

https://bugs.ruby-lang.org/issues/17930

6 files changed, 6 insertions, 6 deletions

diff --git a/test/ruby/marshaltestlib.rb b/test/ruby/marshaltestlib.rb
index 5c48a8d853..7f100b7873 100644
--- a/test/ruby/marshaltestlib.rb
+++ b/test/ruby/marshaltestlib.rb
@@ -112,7 +112,7 @@ module MarshalTestLib
     marshal_equal(Exception.new('foo')) {|o| o.message}
     obj = Object.new
     e = assert_raise(NoMethodError) {obj.no_such_method()}
-    marshal_equal(e) {|o| o.message}
+    marshal_equal(e) {|o| o.message.lines.first.chomp}
   end
 
   def test_exception_subclass
diff --git a/test/ruby/test_marshal.rb b/test/ruby/test_marshal.rb
index d2b4ec169f..5e6891a6a0 100644
--- a/test/ruby/test_marshal.rb
+++ b/test/ruby/test_marshal.rb
@@ -817,7 +817,7 @@ class TestMarshal < Test::Unit::TestCase
       nameerror_test
     rescue NameError => e
       e2 = Marshal.load(Marshal.dump(e))
-      assert_equal(e.message, e2.message)
+      assert_equal(e.message.lines.first.chomp, e2.message.lines.first)
       assert_equal(e.name, e2.name)
       assert_equal(e.backtrace, e2.backtrace)
       assert_nil(e2.backtrace_locations) # temporal
diff --git a/test/ruby/test_module.rb b/test/ruby/test_module.rb
index 84e74693aa..3411c3d701 100644
--- a/test/ruby/test_module.rb
+++ b/test/ruby/test_module.rb
@@ -267,7 +267,7 @@ class TestModule < Test::Unit::TestCase
     ].each do |name, msg|
       expected = "wrong constant name %s" % name
       msg = "#{msg}#{': ' if msg}wrong constant name #{name.dump}"
-      assert_raise_with_message(NameError, expected, "#{msg} to #{m}") do
+      assert_raise_with_message(NameError, Regexp.compile(Regexp.quote(expected)), "#{msg} to #{m}") do
         yield name
       end
     end
diff --git a/test/ruby/test_name_error.rb b/test/ruby/test_name_error.rb
index 813a976e96..8fcc2dcb26 100644
--- a/test/ruby/test_name_error.rb
+++ b/test/ruby/test_name_error.rb
@@ -151,6 +151,6 @@ class TestNameError < Test::Unit::TestCase
     error = assert_raise(NameError) do
       receiver::FOO
     end
-    assert_equal "uninitialized constant #{'A' * 120}::FOO", error.message
+    assert_match /\Auninitialized constant #{'A' * 120}::FOO$/, error.message
   end
 end
diff --git a/test/ruby/test_nomethod_error.rb b/test/ruby/test_nomethod_error.rb
index 8b81052905..321b7ccab2 100644
--- a/test/ruby/test_nomethod_error.rb
+++ b/test/ruby/test_nomethod_error.rb
@@ -86,7 +86,7 @@ class TestNoMethodError < Test::Unit::TestCase
     str = "\u2600"
     id = :"\u2604"
     msg = "undefined method `#{id}' for \"#{str}\":String"
-    assert_raise_with_message(NoMethodError, msg, bug3237) do
+    assert_raise_with_message(NoMethodError, Regexp.compile(Regexp.quote(msg)), bug3237) do
       str.__send__(id)
     end
   end
diff --git a/test/ruby/test_object.rb b/test/ruby/test_object.rb
index 774b707742..83208bbcdb 100644
--- a/test/ruby/test_object.rb
+++ b/test/ruby/test_object.rb
@@ -777,7 +777,7 @@ class TestObject < Test::Unit::TestCase
     e = assert_raise(NoMethodError) {
       o.never_defined_test_no_superclass_method
     }
-    assert_equal(m1, e.message, bug2312)
+    assert_equal(m1.lines.first, e.message.lines.first, bug2312)
   end
 
   def test_superclass_method