refactor ascription

src/parser/grammar/items/consts.rs

@@ -13,8 +13,7 @@ fn const_or_static(p: &mut Parser, kw: SyntaxKind) {
     p.bump();
     p.eat(MUT_KW); // TODO: validator to forbid const mut
     name(p);
-    p.expect(COLON);
-    types::type_(p);
+    types::ascription(p);
     p.expect(EQ);
     expressions::expr(p);
     p.expect(SEMI);

src/parser/grammar/items/mod.rs

@@ -279,8 +279,8 @@ fn let_stmt(p: &mut Parser) {
         let m = p.start();
         p.bump();
         patterns::pattern(p);
-        if p.eat(COLON) {
-            types::type_(p);
+        if p.at(COLON) {
+            types::ascription(p);
         }
         if p.eat(EQ) {
             expressions::expr(p);

src/parser/grammar/types.rs

@@ -17,6 +17,11 @@ pub(super) fn type_(p: &mut Parser) {
     }
 }
 
+pub(super) fn ascription(p: &mut Parser) {
+    p.expect(COLON);
+    type_(p)
+}
+
 fn type_no_plus(p: &mut Parser) {
     type_(p);
 }