Correctly parse negated literals as const args

Author: jonas-schievink

crates/parser/src/grammar/type_args.rs

@@ -59,6 +59,15 @@ fn generic_arg(p: &mut Parser) {
             expressions::literal(p);
             m.complete(p, CONST_ARG);
         }
+        // test const_generic_negated_literal
+        // fn f() { S::<-1> }
+        T![-] => {
+            let lm = p.start();
+            p.bump(T![-]);
+            expressions::literal(p);
+            lm.complete(p, PREFIX_EXPR);
+            m.complete(p, CONST_ARG);
+        }
         _ => {
             types::type_(p);
             m.complete(p, TYPE_ARG);

crates/syntax/test_data/parser/inline/ok/0164_const_generic_negated_literal.rast

@@ -0,0 +1,30 @@
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+  [email protected]
+    [email protected] "fn"
+    [email protected] " "
+    [email protected]
+      [email protected] "f"
+    [email protected]
+      [email protected] "("
+      [email protected] ")"
+    [email protected] " "
+    [email protected]
+      [email protected] "{"
+      [email protected] " "
+      [email protected]
+        [email protected]
+          [email protected]
+            [email protected]
+              [email protected] "S"
+            [email protected]
+              [email protected] "::"
+              [email protected] "<"
+              [email protected]
+                [email protected]
+                  [email protected] "-"
+                  [email protected]
+                    [email protected] "1"
+              [email protected] ">"
+      [email protected] " "
+      [email protected] "}"
+  [email protected] "\n"

crates/syntax/test_data/parser/inline/ok/0164_const_generic_negated_literal.rs

@@ -0,0 +1 @@
+fn f() { S::<-1> }