`Code.string_to_quoted` reports incorrect column for strings with escaped interpolation

[zachallaun]

Elixir and Erlang/OTP versions

$ elixir --version
Erlang/OTP 25 [erts-13.2] [source] [64-bit] [smp:4:4] [ds:4:4:10] [async-threads:1] [jit:ns]

Elixir 1.15.0-dev (35114d3) (compiled with Erlang/OTP 24)

Operating system

Ubuntu-20.04

Current behavior

examples.ex:

"\"foo\""
#   ^   ^
#   5   9

"\"foo\#{hmm}\""
#   ^    ^     ^
#   5    10    16

{:ok, "\"foo\#{hmm}\""}
#   ^    ^    ^    ^  ^
#   5    10   15   20 23

{:ok, "\"foo\#{hmm}\"", 123}
#   ^    ^    ^    ^    ^  ^
#   5    10   15   20   25 28

scratch.exs:

run =
  fn file ->
    file
    |> File.read!()
    |> Code.string_to_quoted!(
      columns: true,
      token_metadata: true,
      literal_encoder: fn literal, meta -> {:ok, {:__block__, meta, [literal]}} end
    )
    |> IO.inspect()
  end

run.("examples.ex")

Run scratch.exs:

# elixir scratch.exs
{:__block__, [],
 [
   {:__block__,
    [
      end_of_expression: [newlines: 2, line: 1, column: 10],
      delimiter: "\"",
      line: 1,
      column: 1
    ], ["\"foo\""]},
   {:__block__,
    [
      end_of_expression: [newlines: 2, line: 5, column: 15],
      delimiter: "\"",
      line: 5,
      column: 1
    ], ["\"foo\#{hmm}\""]},
   {:__block__,
    [
      end_of_expression: [newlines: 2, line: 9, column: 22],
      closing: [line: 9, column: 21],
      line: 9,
      column: 1
    ],
    [
      {{:__block__, [line: 9, column: 2], [:ok]},
       {:__block__, [delimiter: "\"", line: 9, column: 7], ["\"foo\#{hmm}\""]}}
    ]},
   {:{}, [closing: [line: 13, column: 26], line: 13, column: 1],
    [
      {:__block__, [line: 13, column: 2], [:ok]},
      {:__block__, [delimiter: "\"", line: 13, column: 7], ["\"foo\#{hmm}\""]},
      {:__block__, [token: "123", line: 13, column: 23], ~c"{"}
    ]}
 ]}

The end_of_expression column for the second example is reported as 15. The closing column for the third and fourth examples are reported as 21 and 26 , respectively.

Expected behavior

The end_of_expression column for the second example should (I believe) be 17, and the closing columns for examples three and four should be 23 and 28.