From b2be998b7b0beb48806cd3a1552e44100b12ddb6 Mon Sep 17 00:00:00 2001
From: Aleksey Kladov <aleksey.kladov@gmail.com>
Date: Thu, 5 Sep 2019 19:53:07 +0300
Subject: [PATCH] better error recovery for use trees

---
 crates/ra_parser/src/grammar/items.rs         |  2 +-
 .../ra_parser/src/grammar/items/use_item.rs   |  5 +-
 .../parser/err/0002_duplicate_shebang.txt     |  2 +-
 .../test_data/parser/err/0035_use_recover.rs  |  5 ++
 .../test_data/parser/err/0035_use_recover.txt | 54 +++++++++++++++++++
 5 files changed, 65 insertions(+), 3 deletions(-)
 create mode 100644 crates/ra_syntax/test_data/parser/err/0035_use_recover.rs
 create mode 100644 crates/ra_syntax/test_data/parser/err/0035_use_recover.txt

diff --git a/crates/ra_parser/src/grammar/items.rs b/crates/ra_parser/src/grammar/items.rs
index 6d426206e9..b4327b78f4 100644
--- a/crates/ra_parser/src/grammar/items.rs
+++ b/crates/ra_parser/src/grammar/items.rs
@@ -31,7 +31,7 @@ pub(super) enum ItemFlavor {
 
 pub(super) const ITEM_RECOVERY_SET: TokenSet = token_set![
     FN_KW, STRUCT_KW, ENUM_KW, IMPL_KW, TRAIT_KW, CONST_KW, STATIC_KW, LET_KW, MOD_KW, PUB_KW,
-    CRATE_KW
+    CRATE_KW, USE_KW
 ];
 
 pub(super) fn item_or_macro(p: &mut Parser, stop_on_r_curly: bool, flavor: ItemFlavor) {
diff --git a/crates/ra_parser/src/grammar/items/use_item.rs b/crates/ra_parser/src/grammar/items/use_item.rs
index c0c7d0ec6f..83a65e2265 100644
--- a/crates/ra_parser/src/grammar/items/use_item.rs
+++ b/crates/ra_parser/src/grammar/items/use_item.rs
@@ -101,7 +101,10 @@ fn use_tree(p: &mut Parser) {
         }
         _ => {
             m.abandon(p);
-            p.err_and_bump("expected one of `*`, `::`, `{`, `self`, `super` or an indentifier");
+            p.err_recover(
+                "expected one of `*`, `::`, `{`, `self`, `super` or an identifier",
+                ITEM_RECOVERY_SET,
+            );
             return;
         }
     }
diff --git a/crates/ra_syntax/test_data/parser/err/0002_duplicate_shebang.txt b/crates/ra_syntax/test_data/parser/err/0002_duplicate_shebang.txt
index 84867026f4..bdb5fa6c5a 100644
--- a/crates/ra_syntax/test_data/parser/err/0002_duplicate_shebang.txt
+++ b/crates/ra_syntax/test_data/parser/err/0002_duplicate_shebang.txt
@@ -28,7 +28,7 @@ SOURCE_FILE@[0; 42)
   WHITESPACE@[41; 42) "\n"
 error 23: expected `[`
 error 23: expected an item
-error 27: expected one of `*`, `::`, `{`, `self`, `super` or an indentifier
+error 27: expected one of `*`, `::`, `{`, `self`, `super` or an identifier
 error 28: expected SEMI
 error 31: expected EXCL
 error 31: expected `{`, `[`, `(`
diff --git a/crates/ra_syntax/test_data/parser/err/0035_use_recover.rs b/crates/ra_syntax/test_data/parser/err/0035_use_recover.rs
new file mode 100644
index 0000000000..4a26681262
--- /dev/null
+++ b/crates/ra_syntax/test_data/parser/err/0035_use_recover.rs
@@ -0,0 +1,5 @@
+use foo::bar;
+use
+use crate::baz;
+use
+fn f() {}
diff --git a/crates/ra_syntax/test_data/parser/err/0035_use_recover.txt b/crates/ra_syntax/test_data/parser/err/0035_use_recover.txt
new file mode 100644
index 0000000000..6368408288
--- /dev/null
+++ b/crates/ra_syntax/test_data/parser/err/0035_use_recover.txt
@@ -0,0 +1,54 @@
+SOURCE_FILE@[0; 48)
+  USE_ITEM@[0; 13)
+    USE_KW@[0; 3) "use"
+    WHITESPACE@[3; 4) " "
+    USE_TREE@[4; 12)
+      PATH@[4; 12)
+        PATH@[4; 7)
+          PATH_SEGMENT@[4; 7)
+            NAME_REF@[4; 7)
+              IDENT@[4; 7) "foo"
+        COLONCOLON@[7; 9) "::"
+        PATH_SEGMENT@[9; 12)
+          NAME_REF@[9; 12)
+            IDENT@[9; 12) "bar"
+    SEMI@[12; 13) ";"
+  WHITESPACE@[13; 14) "\n"
+  USE_ITEM@[14; 17)
+    USE_KW@[14; 17) "use"
+  WHITESPACE@[17; 18) "\n"
+  USE_ITEM@[18; 33)
+    USE_KW@[18; 21) "use"
+    WHITESPACE@[21; 22) " "
+    USE_TREE@[22; 32)
+      PATH@[22; 32)
+        PATH@[22; 27)
+          PATH_SEGMENT@[22; 27)
+            CRATE_KW@[22; 27) "crate"
+        COLONCOLON@[27; 29) "::"
+        PATH_SEGMENT@[29; 32)
+          NAME_REF@[29; 32)
+            IDENT@[29; 32) "baz"
+    SEMI@[32; 33) ";"
+  WHITESPACE@[33; 34) "\n"
+  USE_ITEM@[34; 37)
+    USE_KW@[34; 37) "use"
+  WHITESPACE@[37; 38) "\n"
+  FN_DEF@[38; 47)
+    FN_KW@[38; 40) "fn"
+    WHITESPACE@[40; 41) " "
+    NAME@[41; 42)
+      IDENT@[41; 42) "f"
+    PARAM_LIST@[42; 44)
+      L_PAREN@[42; 43) "("
+      R_PAREN@[43; 44) ")"
+    WHITESPACE@[44; 45) " "
+    BLOCK_EXPR@[45; 47)
+      BLOCK@[45; 47)
+        L_CURLY@[45; 46) "{"
+        R_CURLY@[46; 47) "}"
+  WHITESPACE@[47; 48) "\n"
+error 17: expected one of `*`, `::`, `{`, `self`, `super` or an identifier
+error 17: expected SEMI
+error 37: expected one of `*`, `::`, `{`, `self`, `super` or an identifier
+error 37: expected SEMI