Merge #2641

2641: Parse const generics r=matklad a=roblabla

Adds very primitive support for parsing const generics (`const IDENT: TY`) so that rust-analyzer stops complaining about the syntax being invalid.

Fixes #1574
Fixes #2281 

Co-authored-by: roblabla <[email protected]>

2 files changed, 12 insertions, 0 deletions

diff --git a/crates/ra_parser/src/grammar/type_params.rs b/crates/ra_parser/src/grammar/type_params.rs
index 34406b5bd..50e4900c3 100644
--- a/crates/ra_parser/src/grammar/type_params.rs
+++ b/crates/ra_parser/src/grammar/type_params.rs
@@ -25,6 +25,7 @@ fn type_param_list(p: &mut Parser) {
         match p.current() {
             LIFETIME => lifetime_param(p, m),
             IDENT => type_param(p, m),
+            CONST_KW => type_const_param(p, m),
             _ => {
                 m.abandon(p);
                 p.err_and_bump("expected type parameter")
@@ -62,6 +63,16 @@ fn type_param(p: &mut Parser, m: Marker) {
     m.complete(p, TYPE_PARAM);
 }
 
+// test const_param
+// struct S<const N: u32>;
+fn type_const_param(p: &mut Parser, m: Marker) {
+    assert!(p.at(CONST_KW));
+    p.bump(T![const]);
+    name(p);
+    types::ascription(p);
+    m.complete(p, CONST_PARAM);
+}
+
 // test type_param_bounds
 // struct S<T: 'a + ?Sized + (Copy)>;
 pub(super) fn bounds(p: &mut Parser) {
diff --git a/crates/ra_parser/src/syntax_kind/generated.rs b/crates/ra_parser/src/syntax_kind/generated.rs
index afe4ce51a..af2945f57 100644
--- a/crates/ra_parser/src/syntax_kind/generated.rs
+++ b/crates/ra_parser/src/syntax_kind/generated.rs
@@ -229,6 +229,7 @@ pub enum SyntaxKind {
     TYPE_PARAM_LIST,
     LIFETIME_PARAM,
     TYPE_PARAM,
+    CONST_PARAM,
     TYPE_ARG_LIST,
     LIFETIME_ARG,
     TYPE_ARG,