8 files changed, 203 insertions, 133 deletions

diff --git a/crates/libsyntax2/src/grammar/expressions/atom.rs b/crates/libsyntax2/src/grammar/expressions/atom.rs
index 9d98340af..417366026 100644
--- a/crates/libsyntax2/src/grammar/expressions/atom.rs
+++ b/crates/libsyntax2/src/grammar/expressions/atom.rs
@@ -148,7 +148,11 @@ fn lambda_expr(p: &mut Parser) -> CompletedMarker {
     p.eat(MOVE_KW);
     params::param_list_opt_types(p);
     if opt_fn_ret_type(p) {
-        block(p);
+        if p.at(L_CURLY) {
+            block(p);
+        } else {
+            p.error("expected a block");
+        }
     } else {
         expr(p);
     }
@@ -254,6 +258,17 @@ fn match_expr(p: &mut Parser) -> CompletedMarker {
     let m = p.start();
     p.bump();
     expr_no_struct(p);
+    if p.at(L_CURLY) {
+        match_arm_list(p);
+    } else {
+        p.error("expected `{`")
+    }
+    m.complete(p, MATCH_EXPR)
+}
+
+fn match_arm_list(p: &mut Parser) {
+    assert!(p.at(L_CURLY));
+    let m = p.start();
     p.eat(L_CURLY);
     while !p.at(EOF) && !p.at(R_CURLY) {
         // test match_arms_commas
@@ -271,7 +286,7 @@ fn match_expr(p: &mut Parser) -> CompletedMarker {
         }
     }
     p.expect(R_CURLY);
-    m.complete(p, MATCH_EXPR)
+    m.complete(p, MATCH_ARM_LIST);
 }
 
 // test match_arm
@@ -307,62 +322,10 @@ pub(super) fn block_expr(p: &mut Parser) -> CompletedMarker {
     assert!(p.at(L_CURLY) || p.at(UNSAFE_KW) && p.nth(1) == L_CURLY);
     let m = p.start();
     p.eat(UNSAFE_KW);
-    p.bump();
-    while !p.at(EOF) && !p.at(R_CURLY) {
-        match p.current() {
-            LET_KW => let_stmt(p),
-            _ => {
-                // test block_items
-                // fn a() { fn b() {} }
-                let m = p.start();
-                match items::maybe_item(p, items::ItemFlavor::Mod) {
-                    items::MaybeItem::Item(kind) => {
-                        m.complete(p, kind);
-                    }
-                    items::MaybeItem::Modifiers => {
-                        m.abandon(p);
-                        p.error("expected an item");
-                    }
-                    // test pub_expr
-                    // fn foo() { pub 92; } //FIXME
-                    items::MaybeItem::None => {
-                        let is_blocklike = expressions::expr_stmt(p) == BlockLike::Block;
-                        if p.eat(SEMI) || (is_blocklike && !p.at(R_CURLY)) {
-                            m.complete(p, EXPR_STMT);
-                        } else {
-                            m.abandon(p);
-                        }
-                    }
-                }
-            }
-        }
-    }
-    p.expect(R_CURLY);
+    block(p);
     m.complete(p, BLOCK_EXPR)
 }
 
-// test let_stmt;
-// fn foo() {
-//     let a;
-//     let b: i32;
-//     let c = 92;
-//     let d: i32 = 92;
-// }
-fn let_stmt(p: &mut Parser) {
-    assert!(p.at(LET_KW));
-    let m = p.start();
-    p.bump();
-    patterns::pattern(p);
-    if p.at(COLON) {
-        types::ascription(p);
-    }
-    if p.eat(EQ) {
-        expressions::expr(p);
-    }
-    p.expect(SEMI);
-    m.complete(p, LET_STMT);
-}
-
 // test return_expr
 // fn foo() {
 //     return;
diff --git a/crates/libsyntax2/src/grammar/expressions/mod.rs b/crates/libsyntax2/src/grammar/expressions/mod.rs
index 9ce0c1f8f..e133c1d9b 100644
--- a/crates/libsyntax2/src/grammar/expressions/mod.rs
+++ b/crates/libsyntax2/src/grammar/expressions/mod.rs
@@ -26,11 +26,62 @@ fn expr_no_struct(p: &mut Parser) {
 // fn c() { 1; 2; }
 // fn d() { 1; 2 }
 pub(super) fn block(p: &mut Parser) {
-    if !p.at(L_CURLY) {
-        p.error("expected block");
-        return;
+    assert!(p.at(L_CURLY));
+    let m = p.start();
+    p.bump();
+    while !p.at(EOF) && !p.at(R_CURLY) {
+        match p.current() {
+            LET_KW => let_stmt(p),
+            _ => {
+                // test block_items
+                // fn a() { fn b() {} }
+                let m = p.start();
+                match items::maybe_item(p, items::ItemFlavor::Mod) {
+                    items::MaybeItem::Item(kind) => {
+                        m.complete(p, kind);
+                    }
+                    items::MaybeItem::Modifiers => {
+                        m.abandon(p);
+                        p.error("expected an item");
+                    }
+                    // test pub_expr
+                    // fn foo() { pub 92; } //FIXME
+                    items::MaybeItem::None => {
+                        let is_blocklike = expressions::expr_stmt(p) == BlockLike::Block;
+                        if p.eat(SEMI) || (is_blocklike && !p.at(R_CURLY)) {
+                            m.complete(p, EXPR_STMT);
+                        } else {
+                            m.abandon(p);
+                        }
+                    }
+                }
+            }
+        }
+    }
+    p.expect(R_CURLY);
+    m.complete(p, BLOCK);
+
+    // test let_stmt;
+    // fn foo() {
+    //     let a;
+    //     let b: i32;
+    //     let c = 92;
+    //     let d: i32 = 92;
+    // }
+    fn let_stmt(p: &mut Parser) {
+        assert!(p.at(LET_KW));
+        let m = p.start();
+        p.bump();
+        patterns::pattern(p);
+        if p.at(COLON) {
+            types::ascription(p);
+        }
+        if p.eat(EQ) {
+            expressions::expr(p);
+        }
+        p.expect(SEMI);
+        m.complete(p, LET_STMT);
     }
-    atom::block_expr(p);
 }
 
 #[derive(Clone, Copy)]
@@ -339,7 +390,7 @@ fn path_expr(p: &mut Parser, r: Restrictions) -> CompletedMarker {
     paths::expr_path(p);
     match p.current() {
         L_CURLY if !r.forbid_structs => {
-            struct_lit(p);
+            named_field_list(p);
             m.complete(p, STRUCT_LIT)
         }
         EXCL => {
@@ -356,8 +407,9 @@ fn path_expr(p: &mut Parser, r: Restrictions) -> CompletedMarker {
 //     S { x, y: 32, };
 //     S { x, y: 32, ..Default::default() };
 // }
-fn struct_lit(p: &mut Parser) {
+fn named_field_list(p: &mut Parser) {
     assert!(p.at(L_CURLY));
+    let m = p.start();
     p.bump();
     while !p.at(EOF) && !p.at(R_CURLY) {
         match p.current() {
@@ -367,7 +419,7 @@ fn struct_lit(p: &mut Parser) {
                 if p.eat(COLON) {
                     expr(p);
                 }
-                m.complete(p, STRUCT_LIT_FIELD);
+                m.complete(p, NAMED_FIELD);
             }
             DOTDOT => {
                 p.bump();
@@ -380,4 +432,5 @@ fn struct_lit(p: &mut Parser) {
         }
     }
     p.expect(R_CURLY);
+    m.complete(p, NAMED_FIELD_LIST);
 }
diff --git a/crates/libsyntax2/src/grammar/items/mod.rs b/crates/libsyntax2/src/grammar/items/mod.rs
index 18b681ee2..d236fb506 100644
--- a/crates/libsyntax2/src/grammar/items/mod.rs
+++ b/crates/libsyntax2/src/grammar/items/mod.rs
@@ -194,8 +194,8 @@ fn items_without_modifiers(p: &mut Parser) -> Option<SyntaxKind> {
         // extern {}
         EXTERN_KW if la == L_CURLY || ((la == STRING || la == RAW_STRING) && p.nth(2) == L_CURLY) => {
             abi(p);
-            extern_block(p);
-            EXTERN_BLOCK_EXPR
+            extern_item_list(p);
+            EXTERN_BLOCK
         }
         _ => return None,
     };
@@ -212,10 +212,12 @@ fn extern_crate_item(p: &mut Parser) {
     p.expect(SEMI);
 }
 
-fn extern_block(p: &mut Parser) {
+fn extern_item_list(p: &mut Parser) {
     assert!(p.at(L_CURLY));
+    let m = p.start();
     p.bump();
     p.expect(R_CURLY);
+    m.complete(p, EXTERN_ITEM_LIST);
 }
 
 fn function(p: &mut Parser, flavor: ItemFlavor) {
@@ -284,14 +286,22 @@ fn mod_item(p: &mut Parser) {
     p.bump();
 
     name(p);
-    if !p.eat(SEMI) {
-        if p.expect(L_CURLY) {
-            mod_contents(p, true);
-            p.expect(R_CURLY);
-        }
+    if p.at(L_CURLY) {
+        mod_item_list(p);
+    } else if !p.eat(SEMI) {
+        p.error("expected `;` or `{`");
     }
 }
 
+fn mod_item_list(p: &mut Parser) {
+    assert!(p.at(L_CURLY));
+    let m = p.start();
+    p.bump();
+    mod_contents(p, true);
+    p.expect(R_CURLY);
+    m.complete(p, ITEM_LIST);
+}
+
 fn macro_call(p: &mut Parser) -> BlockLike {
     assert!(paths::is_path_start(p));
     paths::use_path(p);
diff --git a/crates/libsyntax2/src/grammar/items/structs.rs b/crates/libsyntax2/src/grammar/items/structs.rs
index cde9d0ae6..ca027d718 100644
--- a/crates/libsyntax2/src/grammar/items/structs.rs
+++ b/crates/libsyntax2/src/grammar/items/structs.rs
@@ -14,7 +14,7 @@ pub(super) fn struct_def(p: &mut Parser) {
                     p.bump();
                     return;
                 }
-                L_CURLY => named_fields(p),
+                L_CURLY => named_field_def_list(p),
                 _ => {
                     //TODO: special case `(` error message
                     p.error("expected `;` or `{`");
@@ -26,9 +26,9 @@ pub(super) fn struct_def(p: &mut Parser) {
             p.bump();
             return;
         }
-        L_CURLY => named_fields(p),
+        L_CURLY => named_field_def_list(p),
         L_PAREN => {
-            pos_fields(p);
+            pos_field_list(p);
             p.expect(SEMI);
         }
         _ => {
@@ -44,46 +44,58 @@ pub(super) fn enum_def(p: &mut Parser) {
     name(p);
     type_params::opt_type_param_list(p);
     type_params::opt_where_clause(p);
-    if p.expect(L_CURLY) {
-        while !p.at(EOF) && !p.at(R_CURLY) {
-            let var = p.start();
-            attributes::outer_attributes(p);
-            if p.at(IDENT) {
-                name(p);
-                match p.current() {
-                    L_CURLY => named_fields(p),
-                    L_PAREN => pos_fields(p),
-                    EQ => {
-                        p.bump();
-                        expressions::expr(p);
-                    }
-                    _ => (),
+    if p.at(L_CURLY) {
+        enum_variant_list(p);
+    } else {
+        p.error("expected `{`")
+    }
+}
+
+fn enum_variant_list(p: &mut Parser) {
+    assert!(p.at(L_CURLY));
+    let m = p.start();
+    p.bump();
+    while !p.at(EOF) && !p.at(R_CURLY) {
+        let var = p.start();
+        attributes::outer_attributes(p);
+        if p.at(IDENT) {
+            name(p);
+            match p.current() {
+                L_CURLY => named_field_def_list(p),
+                L_PAREN => pos_field_list(p),
+                EQ => {
+                    p.bump();
+                    expressions::expr(p);
                 }
-                var.complete(p, ENUM_VARIANT);
-            } else {
-                var.abandon(p);
-                p.err_and_bump("expected enum variant");
-            }
-            if !p.at(R_CURLY) {
-                p.expect(COMMA);
+                _ => (),
             }
+            var.complete(p, ENUM_VARIANT);
+        } else {
+            var.abandon(p);
+            p.err_and_bump("expected enum variant");
+        }
+        if !p.at(R_CURLY) {
+            p.expect(COMMA);
         }
-        p.expect(R_CURLY);
     }
+    p.expect(R_CURLY);
+    m.complete(p, ENUM_VARIANT_LIST);
 }
 
-fn named_fields(p: &mut Parser) {
+fn named_field_def_list(p: &mut Parser) {
     assert!(p.at(L_CURLY));
+    let m = p.start();
     p.bump();
     while !p.at(R_CURLY) && !p.at(EOF) {
-        named_field(p);
+        named_field_def(p);
         if !p.at(R_CURLY) {
             p.expect(COMMA);
         }
     }
     p.expect(R_CURLY);
+    m.complete(p, NAMED_FIELD_DEF_LIST);
 
-    fn named_field(p: &mut Parser) {
+    fn named_field_def(p: &mut Parser) {
         let m = p.start();
         // test field_attrs
         // struct S {
@@ -96,7 +108,7 @@ fn named_fields(p: &mut Parser) {
             name(p);
             p.expect(COLON);
             types::type_(p);
-            m.complete(p, NAMED_FIELD);
+            m.complete(p, NAMED_FIELD_DEF);
         } else {
             m.abandon(p);
             p.err_and_bump("expected field declaration");
@@ -104,7 +116,9 @@ fn named_fields(p: &mut Parser) {
     }
 }
 
-fn pos_fields(p: &mut Parser) {
+fn pos_field_list(p: &mut Parser) {
+    assert!(p.at(L_PAREN));
+    let m = p.start();
     if !p.expect(L_PAREN) {
         return;
     }
@@ -119,4 +133,5 @@ fn pos_fields(p: &mut Parser) {
         }
     }
     p.expect(R_PAREN);
+    m.complete(p, POS_FIELD_LIST);
 }
diff --git a/crates/libsyntax2/src/grammar/items/traits.rs b/crates/libsyntax2/src/grammar/items/traits.rs
index 73ecd4bef..3853ccaab 100644
--- a/crates/libsyntax2/src/grammar/items/traits.rs
+++ b/crates/libsyntax2/src/grammar/items/traits.rs
@@ -11,18 +11,29 @@ pub(super) fn trait_def(p: &mut Parser) {
         type_params::bounds(p);
     }
     type_params::opt_where_clause(p);
-    p.expect(L_CURLY);
-    // test trait_item_items
-    // impl F {
-    //     type A: Clone;
-    //     const B: i32;
-    //     fn foo() {}
-    //     fn bar(&self);
-    // }
+    if p.at(L_CURLY) {
+        trait_item_list(p);
+    } else {
+        p.error("expected `{`");
+    }
+}
+
+// test trait_item_list
+// impl F {
+//     type A: Clone;
+//     const B: i32;
+//     fn foo() {}
+//     fn bar(&self);
+// }
+fn trait_item_list(p: &mut Parser) {
+    assert!(p.at(L_CURLY));
+    let m = p.start();
+    p.bump();
     while !p.at(EOF) && !p.at(R_CURLY) {
         item_or_macro(p, true, ItemFlavor::Trait);
     }
     p.expect(R_CURLY);
+    m.complete(p, ITEM_LIST);
 }
 
 // test impl_item
@@ -45,19 +56,30 @@ pub(super) fn impl_item(p: &mut Parser) {
         types::type_(p);
     }
     type_params::opt_where_clause(p);
-    p.expect(L_CURLY);
+    if p.at(L_CURLY) {
+        impl_item_list(p);
+    } else {
+        p.error("expected `{`");
+    }
+}
+
+// test impl_item_list
+// impl F {
+//     type A = i32;
+//     const B: i32 = 92;
+//     fn foo() {}
+//     fn bar(&self) {}
+// }
+fn impl_item_list(p: &mut Parser) {
+    assert!(p.at(L_CURLY));
+    let m = p.start();
+    p.bump();
 
-    // test impl_item_items
-    // impl F {
-    //     type A = i32;
-    //     const B: i32 = 92;
-    //     fn foo() {}
-    //     fn bar(&self) {}
-    // }
     while !p.at(EOF) && !p.at(R_CURLY) {
         item_or_macro(p, true, ItemFlavor::Mod);
     }
     p.expect(R_CURLY);
+    m.complete(p, ITEM_LIST);
 }
 
 fn choose_type_params_over_qpath(p: &Parser) -> bool {
diff --git a/crates/libsyntax2/src/grammar/items/use_item.rs b/crates/libsyntax2/src/grammar/items/use_item.rs
index 3da40a629..2fbf2234a 100644
--- a/crates/libsyntax2/src/grammar/items/use_item.rs
+++ b/crates/libsyntax2/src/grammar/items/use_item.rs
@@ -20,7 +20,7 @@ fn use_tree(p: &mut Parser) {
             if p.at(COLONCOLON) {
                 p.bump();
             }
-            nested_trees(p);
+            use_tree_list(p);
         }
         _ if paths::is_path_start(p) => {
             paths::use_path(p);
@@ -34,7 +34,7 @@ fn use_tree(p: &mut Parser) {
                         STAR => {
                             p.bump();
                         }
-                        L_CURLY => nested_trees(p),
+                        L_CURLY => use_tree_list(p),
                         _ => {
                             // is this unreachable?
                             p.error("expected `{` or `*`");
@@ -53,8 +53,9 @@ fn use_tree(p: &mut Parser) {
     m.complete(p, USE_TREE);
 }
 
-fn nested_trees(p: &mut Parser) {
+fn use_tree_list(p: &mut Parser) {
     assert!(p.at(L_CURLY));
+    let m = p.start();
     p.bump();
     while !p.at(EOF) && !p.at(R_CURLY) {
         use_tree(p);
@@ -63,4 +64,5 @@ fn nested_trees(p: &mut Parser) {
         }
     }
     p.expect(R_CURLY);
+    m.complete(p, USE_TREE_LIST);
 }
diff --git a/crates/libsyntax2/src/grammar/mod.rs b/crates/libsyntax2/src/grammar/mod.rs
index 25887921b..0f118f12d 100644
--- a/crates/libsyntax2/src/grammar/mod.rs
+++ b/crates/libsyntax2/src/grammar/mod.rs
@@ -144,18 +144,21 @@ fn name_ref(p: &mut Parser) {
 }
 
 fn error_block(p: &mut Parser, message: &str) {
-    assert!(p.at(L_CURLY));
-    let err = p.start();
-    p.error(message);
-    p.bump();
-    let mut level: u32 = 1;
-    while level > 0 && !p.at(EOF) {
-        match p.current() {
-            L_CURLY => level += 1,
-            R_CURLY => level -= 1,
-            _ => (),
+    go(p, Some(message));
+    fn go(p: &mut Parser, message: Option<&str>) {
+        assert!(p.at(L_CURLY));
+        let m = p.start();
+        if let Some(message) = message {
+            p.error(message);
         }
         p.bump();
+        while !p.at(EOF) && !p.at(R_CURLY) {
+            match p.current() {
+                L_CURLY => go(p, None),
+                _ => p.bump(),
+            }
+        }
+        p.eat(R_CURLY);
+        m.complete(p, ERROR);
     }
-    err.complete(p, ERROR);
 }
diff --git a/crates/libsyntax2/src/grammar/patterns.rs b/crates/libsyntax2/src/grammar/patterns.rs
index 71a1d5445..7ddbfa318 100644
--- a/crates/libsyntax2/src/grammar/patterns.rs
+++ b/crates/libsyntax2/src/grammar/patterns.rs
@@ -69,7 +69,7 @@ fn path_pat(p: &mut Parser) -> CompletedMarker {
             TUPLE_STRUCT_PAT
         }
         L_CURLY => {
-            struct_pat_fields(p);
+            field_pat_list(p);
             STRUCT_PAT
         }
         _ => PATH_PAT
@@ -99,15 +99,16 @@ fn tuple_pat_fields(p: &mut Parser) {
     p.expect(R_PAREN);
 }
 
-// test struct_pat_fields
+// test field_pat_list
 // fn foo() {
 //     let S {} = ();
 //     let S { f, ref mut g } = ();
 //     let S { h: _, ..} = ();
 //     let S { h: _, } = ();
 // }
-fn struct_pat_fields(p: &mut Parser) {
+fn field_pat_list(p: &mut Parser) {
     assert!(p.at(L_CURLY));
+    let m = p.start();
     p.bump();
     while !p.at(EOF) && !p.at(R_CURLY) {
         match p.current() {
@@ -126,6 +127,7 @@ fn struct_pat_fields(p: &mut Parser) {
         }
     }
     p.expect(R_CURLY);
+    m.complete(p, FIELD_PAT_LIST);
 }
 
 // test placeholder_pat