Merge #1848

1848: Parse `..` as a full pattern r=matklad a=ecstatic-morse

Resolves #1479.

This PR implements [RFC 2707](https://github.com/rust-lang/rfcs/pull/2707) in the parser. It introduces a new `DotDotPat` AST node modeled on `PlaceholderPat` and changes the parsing of tuple and slice patterns to conform to the RFC.

Notably, this PR does *not* change the resulting AST when `..` appears in a struct pattern (e.g. `Struct { a, b: c, .. }`). I *think* this is the behavior mandated by RFC 2707, but someone should confirm this.

Co-authored-by: Dylan MacKenzie <[email protected]>

1 files changed, 2 insertions, 1 deletions

diff --git a/crates/ra_syntax/test_data/parser/inline/ok/0024_slice_pat.txt b/crates/ra_syntax/test_data/parser/inline/ok/0024_slice_pat.txt
index c1d669e54..48aaeaf07 100644
--- a/crates/ra_syntax/test_data/parser/inline/ok/0024_slice_pat.txt
+++ b/crates/ra_syntax/test_data/parser/inline/ok/0024_slice_pat.txt
@@ -27,7 +27,8 @@ SOURCE_FILE@[0; 39)
                 IDENT@[24; 25) "b"
             COMMA@[25; 26) ","
             WHITESPACE@[26; 27) " "
-            DOTDOT@[27; 29) ".."
+            DOT_DOT_PAT@[27; 29)
+              DOTDOT@[27; 29) ".."
             R_BRACK@[29; 30) "]"
           WHITESPACE@[30; 31) " "
           EQ@[31; 32) "="