Auto merge of #52994 - varkor:trim_direction, r=alexcrichton

Add trim_start, trim_end etc.; deprecate trim_left, trim_right, etc. in future

Adds the methods: `trim_start`, `trim_end`, `trim_start_matches` and `trim_end_matches`.
Deprecates `trim_left`, `trim_right`, `trim_left_matches` and `trim_right_matches` starting from Rust 1.33.0, three versions from when they'll initially be marked as being deprecated, using the future deprecation from https://github.com/rust-lang/rust/issues/30785 and https://github.com/rust-lang/rust/pull/51681.

Fixes https://github.com/rust-lang/rust/issues/30459.

1 files changed, 38 insertions, 30 deletions

diff --git a/src/liballoc/tests/str.rs b/src/liballoc/tests/str.rs
index 6275c7bb112..a5fa7f0c4d9 100644
--- a/src/liballoc/tests/str.rs
+++ b/src/liballoc/tests/str.rs
@@ -727,33 +727,33 @@ fn test_is_char_boundary() {
 }
 
 #[test]
-fn test_trim_left_matches() {
+fn test_trim_start_matches() {
     let v: &[char] = &[];
-    assert_eq!(" *** foo *** ".trim_left_matches(v), " *** foo *** ");
+    assert_eq!(" *** foo *** ".trim_start_matches(v), " *** foo *** ");
     let chars: &[char] = &['*', ' '];
-    assert_eq!(" *** foo *** ".trim_left_matches(chars), "foo *** ");
-    assert_eq!(" ***  *** ".trim_left_matches(chars), "");
-    assert_eq!("foo *** ".trim_left_matches(chars), "foo *** ");
+    assert_eq!(" *** foo *** ".trim_start_matches(chars), "foo *** ");
+    assert_eq!(" ***  *** ".trim_start_matches(chars), "");
+    assert_eq!("foo *** ".trim_start_matches(chars), "foo *** ");
 
-    assert_eq!("11foo1bar11".trim_left_matches('1'), "foo1bar11");
+    assert_eq!("11foo1bar11".trim_start_matches('1'), "foo1bar11");
     let chars: &[char] = &['1', '2'];
-    assert_eq!("12foo1bar12".trim_left_matches(chars), "foo1bar12");
-    assert_eq!("123foo1bar123".trim_left_matches(|c: char| c.is_numeric()), "foo1bar123");
+    assert_eq!("12foo1bar12".trim_start_matches(chars), "foo1bar12");
+    assert_eq!("123foo1bar123".trim_start_matches(|c: char| c.is_numeric()), "foo1bar123");
 }
 
 #[test]
-fn test_trim_right_matches() {
+fn test_trim_end_matches() {
     let v: &[char] = &[];
-    assert_eq!(" *** foo *** ".trim_right_matches(v), " *** foo *** ");
+    assert_eq!(" *** foo *** ".trim_end_matches(v), " *** foo *** ");
     let chars: &[char] = &['*', ' '];
-    assert_eq!(" *** foo *** ".trim_right_matches(chars), " *** foo");
-    assert_eq!(" ***  *** ".trim_right_matches(chars), "");
-    assert_eq!(" *** foo".trim_right_matches(chars), " *** foo");
+    assert_eq!(" *** foo *** ".trim_end_matches(chars), " *** foo");
+    assert_eq!(" ***  *** ".trim_end_matches(chars), "");
+    assert_eq!(" *** foo".trim_end_matches(chars), " *** foo");
 
-    assert_eq!("11foo1bar11".trim_right_matches('1'), "11foo1bar");
+    assert_eq!("11foo1bar11".trim_end_matches('1'), "11foo1bar");
     let chars: &[char] = &['1', '2'];
-    assert_eq!("12foo1bar12".trim_right_matches(chars), "12foo1bar");
-    assert_eq!("123foo1bar123".trim_right_matches(|c: char| c.is_numeric()), "123foo1bar");
+    assert_eq!("12foo1bar12".trim_end_matches(chars), "12foo1bar");
+    assert_eq!("123foo1bar123".trim_end_matches(|c: char| c.is_numeric()), "123foo1bar");
 }
 
 #[test]
@@ -772,23 +772,23 @@ fn test_trim_matches() {
 }
 
 #[test]
-fn test_trim_left() {
-    assert_eq!("".trim_left(), "");
-    assert_eq!("a".trim_left(), "a");
-    assert_eq!("    ".trim_left(), "");
-    assert_eq!("     blah".trim_left(), "blah");
-    assert_eq!("   \u{3000}  wut".trim_left(), "wut");
-    assert_eq!("hey ".trim_left(), "hey ");
+fn test_trim_start() {
+    assert_eq!("".trim_start(), "");
+    assert_eq!("a".trim_start(), "a");
+    assert_eq!("    ".trim_start(), "");
+    assert_eq!("     blah".trim_start(), "blah");
+    assert_eq!("   \u{3000}  wut".trim_start(), "wut");
+    assert_eq!("hey ".trim_start(), "hey ");
 }
 
 #[test]
-fn test_trim_right() {
-    assert_eq!("".trim_right(), "");
-    assert_eq!("a".trim_right(), "a");
-    assert_eq!("    ".trim_right(), "");
-    assert_eq!("blah     ".trim_right(), "blah");
-    assert_eq!("wut   \u{3000}  ".trim_right(), "wut");
-    assert_eq!(" hey".trim_right(), " hey");
+fn test_trim_end() {
+    assert_eq!("".trim_end(), "");
+    assert_eq!("a".trim_end(), "a");
+    assert_eq!("    ".trim_end(), "");
+    assert_eq!("blah     ".trim_end(), "blah");
+    assert_eq!("wut   \u{3000}  ".trim_end(), "wut");
+    assert_eq!(" hey".trim_end(), " hey");
 }
 
 #[test]
@@ -1518,12 +1518,20 @@ fn trim_ws() {
                     "a \t  ");
     assert_eq!(" \t  a \t  ".trim_right_matches(|c: char| c.is_whitespace()),
                " \t  a");
+    assert_eq!(" \t  a \t  ".trim_start_matches(|c: char| c.is_whitespace()),
+                    "a \t  ");
+    assert_eq!(" \t  a \t  ".trim_end_matches(|c: char| c.is_whitespace()),
+               " \t  a");
     assert_eq!(" \t  a \t  ".trim_matches(|c: char| c.is_whitespace()),
                     "a");
     assert_eq!(" \t   \t  ".trim_left_matches(|c: char| c.is_whitespace()),
                          "");
     assert_eq!(" \t   \t  ".trim_right_matches(|c: char| c.is_whitespace()),
                "");
+    assert_eq!(" \t   \t  ".trim_start_matches(|c: char| c.is_whitespace()),
+                         "");
+    assert_eq!(" \t   \t  ".trim_end_matches(|c: char| c.is_whitespace()),
+               "");
     assert_eq!(" \t   \t  ".trim_matches(|c: char| c.is_whitespace()),
                "");
 }