Support arbitrary discriminants

Closes #3661

3 files changed, 37 insertions, 4 deletions

diff --git a/crates/ra_parser/src/grammar/items/adt.rs b/crates/ra_parser/src/grammar/items/adt.rs
index c777bc9d0..74b9f514b 100644
--- a/crates/ra_parser/src/grammar/items/adt.rs
+++ b/crates/ra_parser/src/grammar/items/adt.rs
@@ -83,12 +83,14 @@ pub(crate) fn enum_variant_list(p: &mut Parser) {
             match p.current() {
                 T!['{'] => record_field_def_list(p),
                 T!['('] => tuple_field_def_list(p),
-                T![=] => {
-                    p.bump(T![=]);
-                    expressions::expr(p);
-                }
                 _ => (),
             }
+
+            // test variant_discriminant
+            // enum E { X(i32) = 10 }
+            if p.eat(T![=]) {
+                expressions::expr(p);
+            }
             var.complete(p, ENUM_VARIANT);
         } else {
             var.abandon(p);
diff --git a/crates/ra_syntax/test_data/parser/inline/ok/0157_variant_discriminant.rs b/crates/ra_syntax/test_data/parser/inline/ok/0157_variant_discriminant.rs
new file mode 100644
index 000000000..c8c5c0f17
--- /dev/null
+++ b/crates/ra_syntax/test_data/parser/inline/ok/0157_variant_discriminant.rs
@@ -0,0 +1 @@
+enum E { X(i32) = 10 }
diff --git a/crates/ra_syntax/test_data/parser/inline/ok/0157_variant_discriminant.txt b/crates/ra_syntax/test_data/parser/inline/ok/0157_variant_discriminant.txt
new file mode 100644
index 000000000..a378dd80b
--- /dev/null
+++ b/crates/ra_syntax/test_data/parser/inline/ok/0157_variant_discriminant.txt
@@ -0,0 +1,30 @@
+SOURCE_FILE@[0; 23)
+  ENUM_DEF@[0; 22)
+    ENUM_KW@[0; 4) "enum"
+    WHITESPACE@[4; 5) " "
+    NAME@[5; 6)
+      IDENT@[5; 6) "E"
+    WHITESPACE@[6; 7) " "
+    ENUM_VARIANT_LIST@[7; 22)
+      L_CURLY@[7; 8) "{"
+      WHITESPACE@[8; 9) " "
+      ENUM_VARIANT@[9; 20)
+        NAME@[9; 10)
+          IDENT@[9; 10) "X"
+        TUPLE_FIELD_DEF_LIST@[10; 15)
+          L_PAREN@[10; 11) "("
+          TUPLE_FIELD_DEF@[11; 14)
+            PATH_TYPE@[11; 14)
+              PATH@[11; 14)
+                PATH_SEGMENT@[11; 14)
+                  NAME_REF@[11; 14)
+                    IDENT@[11; 14) "i32"
+          R_PAREN@[14; 15) ")"
+        WHITESPACE@[15; 16) " "
+        EQ@[16; 17) "="
+        WHITESPACE@[17; 18) " "
+        LITERAL@[18; 20)
+          INT_NUMBER@[18; 20) "10"
+      WHITESPACE@[20; 21) " "
+      R_CURLY@[21; 22) "}"
+  WHITESPACE@[22; 23) "\n"