Fix regression in parse_util_process_extent

Found on a two-line commandline

    for file in (path base<TAB>
    echo

src/parse_util.rs

@@ -391,7 +391,7 @@ fn job_or_process_extent(
 
     let mut result = cmdsub_range.clone();
     for token in Tokenizer::new(
-        &buff[cmdsub_range],
+        &buff[cmdsub_range.clone()],
         TOK_ACCEPT_UNFINISHED | TOK_SHOW_COMMENTS,
     ) {
         let tok_begin = token.offset();
@@ -408,10 +408,10 @@ fn job_or_process_extent(
             {
                 if tok_begin >= pos {
                     finished = true;
-                    result.end = tok_begin;
+                    result.end = cmdsub_range.start + tok_begin;
                 } else {
                     // Statement at cursor might start after this token.
-                    result.start = tok_begin + token.length();
+                    result.start = cmdsub_range.start + tok_begin + token.length();
                     out_tokens.as_mut().map(|tokens| tokens.clear());
                 }
                 continue; // Do not add this to tokens

src/tests/parse_util.rs

@@ -5,7 +5,9 @@ use crate::parse_constants::{
     ERROR_NOT_ARGV_AT, ERROR_NOT_ARGV_COUNT, ERROR_NOT_ARGV_STAR, ERROR_NOT_PID, ERROR_NOT_STATUS,
     ERROR_NO_VAR_NAME,
 };
-use crate::parse_util::{parse_util_detect_errors, BOOL_AFTER_BACKGROUND_ERROR_MSG};
+use crate::parse_util::{
+    parse_util_detect_errors, parse_util_process_extent, BOOL_AFTER_BACKGROUND_ERROR_MSG,
+};
 use crate::tests::prelude::*;
 use crate::wchar::prelude::*;
 
@@ -85,3 +87,16 @@ fn test_error_messages() {
         BOOL_AFTER_BACKGROUND_ERROR_MSG
     );
 }
+
+#[test]
+fn test_parse_util_process_extent() {
+    macro_rules! validate {
+        ($commandline:literal, $cursor:expr, $expected_range:expr) => {
+            assert_eq!(
+                parse_util_process_extent(L!($commandline), $cursor, None),
+                $expected_range
+            );
+        };
+    }
+    validate!("for file in (path base\necho", 22, 13..22);
+}