From dea6ed73fac6f3f4daf38b1cb6df4c8fb68872b7 Mon Sep 17 00:00:00 2001
From: Aleksey Kladov <aleksey.kladov@gmail.com>
Date: Tue, 28 Aug 2018 19:35:09 +0300
Subject: better pattern recovery

---
 crates/libsyntax2/src/ast/generated.rs    | 6 ++++++
 crates/libsyntax2/src/grammar.ron         | 2 +-
 crates/libsyntax2/src/grammar/patterns.rs | 6 +++++-
 3 files changed, 12 insertions(+), 2 deletions(-)

(limited to 'crates/libsyntax2/src')

diff --git a/crates/libsyntax2/src/ast/generated.rs b/crates/libsyntax2/src/ast/generated.rs
index 2b400b847..999023e3d 100644
--- a/crates/libsyntax2/src/ast/generated.rs
+++ b/crates/libsyntax2/src/ast/generated.rs
@@ -893,6 +893,8 @@ pub enum ModuleItem<'a> {
     ImplItem(ImplItem<'a>),
     UseItem(UseItem<'a>),
     ExternCrateItem(ExternCrateItem<'a>),
+    ConstDef(ConstDef<'a>),
+    StaticDef(StaticDef<'a>),
 }
 
 impl<'a> AstNode<'a> for ModuleItem<'a> {
@@ -905,6 +907,8 @@ impl<'a> AstNode<'a> for ModuleItem<'a> {
             IMPL_ITEM => Some(ModuleItem::ImplItem(ImplItem { syntax })),
             USE_ITEM => Some(ModuleItem::UseItem(UseItem { syntax })),
             EXTERN_CRATE_ITEM => Some(ModuleItem::ExternCrateItem(ExternCrateItem { syntax })),
+            CONST_DEF => Some(ModuleItem::ConstDef(ConstDef { syntax })),
+            STATIC_DEF => Some(ModuleItem::StaticDef(StaticDef { syntax })),
             _ => None,
         }
     }
@@ -917,6 +921,8 @@ impl<'a> AstNode<'a> for ModuleItem<'a> {
             ModuleItem::ImplItem(inner) => inner.syntax(),
             ModuleItem::UseItem(inner) => inner.syntax(),
             ModuleItem::ExternCrateItem(inner) => inner.syntax(),
+            ModuleItem::ConstDef(inner) => inner.syntax(),
+            ModuleItem::StaticDef(inner) => inner.syntax(),
         }
     }
 }
diff --git a/crates/libsyntax2/src/grammar.ron b/crates/libsyntax2/src/grammar.ron
index 8055a4687..f8fa7b694 100644
--- a/crates/libsyntax2/src/grammar.ron
+++ b/crates/libsyntax2/src/grammar.ron
@@ -334,7 +334,7 @@ Grammar(
         ),
         "ModuleItem": (
             enum: ["StructDef", "EnumDef", "FnDef", "TraitDef", "ImplItem",
-                   "UseItem", "ExternCrateItem" ]
+                   "UseItem", "ExternCrateItem", "ConstDef", "StaticDef" ]
         ),
 
         "TupleExpr": (),
diff --git a/crates/libsyntax2/src/grammar/patterns.rs b/crates/libsyntax2/src/grammar/patterns.rs
index 114964651..065570b99 100644
--- a/crates/libsyntax2/src/grammar/patterns.rs
+++ b/crates/libsyntax2/src/grammar/patterns.rs
@@ -22,6 +22,10 @@ pub(super) fn pattern(p: &mut Parser) {
     }
 }
 
+const PAT_RECOVERY_SET: TokenSet =
+    token_set![LET_KW, IF_KW, WHILE_KW, LOOP_KW, MATCH_KW];
+
+
 fn atom_pat(p: &mut Parser) -> Option<CompletedMarker> {
     let la0 = p.nth(0);
     let la1 = p.nth(1);
@@ -52,7 +56,7 @@ fn atom_pat(p: &mut Parser) -> Option<CompletedMarker> {
         L_PAREN => tuple_pat(p),
         L_BRACK => slice_pat(p),
         _ => {
-            p.err_and_bump("expected pattern");
+            p.err_recover("expected pattern", PAT_RECOVERY_SET);
             return None;
         }
     };
-- 
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