From 8a11da40a789e5d73c5c11d69ba87638ddff8676 Mon Sep 17 00:00:00 2001
From: David Tolnay <dtolnay@gmail.com>
Date: Sun, 22 Nov 2020 20:43:00 -0800
Subject: Parse unsafe extern block

---
 crates/parser/src/grammar/items.rs                       | 10 +++++++++-
 .../syntax/test_data/parser/ok/0068_item_modifiers.rast  | 16 ++++++++++++++--
 crates/syntax/test_data/parser/ok/0068_item_modifiers.rs |  2 ++
 3 files changed, 25 insertions(+), 3 deletions(-)

diff --git a/crates/parser/src/grammar/items.rs b/crates/parser/src/grammar/items.rs
index 780bc470a..ad29b82f7 100644
--- a/crates/parser/src/grammar/items.rs
+++ b/crates/parser/src/grammar/items.rs
@@ -112,7 +112,7 @@ pub(super) fn maybe_item(p: &mut Parser, m: Marker) -> Result<(), Marker> {
         has_mods = true;
     }
 
-    if p.at(T![extern]) {
+    if p.at(T![extern]) && p.nth(1) != T!['{'] && (p.nth(1) != STRING || p.nth(2) != T!['{']) {
         has_mods = true;
         abi(p);
     }
@@ -181,6 +181,14 @@ pub(super) fn maybe_item(p: &mut Parser, m: Marker) -> Result<(), Marker> {
         T![type] => {
             type_alias(p, m);
         }
+
+        // unsafe extern "C" {}
+        T![extern] => {
+            abi(p);
+            extern_item_list(p);
+            m.complete(p, EXTERN_BLOCK);
+        }
+
         _ => {
             if !has_visibility && !has_mods {
                 return Err(m);
diff --git a/crates/syntax/test_data/parser/ok/0068_item_modifiers.rast b/crates/syntax/test_data/parser/ok/0068_item_modifiers.rast
index 50a6d8ee9..87eebf185 100644
--- a/crates/syntax/test_data/parser/ok/0068_item_modifiers.rast
+++ b/crates/syntax/test_data/parser/ok/0068_item_modifiers.rast
@@ -1,4 +1,4 @@
-SOURCE_FILE@0..304
+SOURCE_FILE@0..328
   FN@0..17
     ASYNC_KW@0..5 "async"
     WHITESPACE@5..6 " "
@@ -215,4 +215,16 @@ SOURCE_FILE@0..304
     ASSOC_ITEM_LIST@301..303
       L_CURLY@301..302 "{"
       R_CURLY@302..303 "}"
-  WHITESPACE@303..304 "\n"
+  WHITESPACE@303..305 "\n\n"
+  EXTERN_BLOCK@305..327
+    UNSAFE_KW@305..311 "unsafe"
+    WHITESPACE@311..312 " "
+    ABI@312..324
+      EXTERN_KW@312..318 "extern"
+      WHITESPACE@318..319 " "
+      STRING@319..324 "\"C++\""
+    WHITESPACE@324..325 " "
+    EXTERN_ITEM_LIST@325..327
+      L_CURLY@325..326 "{"
+      R_CURLY@326..327 "}"
+  WHITESPACE@327..328 "\n"
diff --git a/crates/syntax/test_data/parser/ok/0068_item_modifiers.rs b/crates/syntax/test_data/parser/ok/0068_item_modifiers.rs
index 8d697c04b..6d27a082c 100644
--- a/crates/syntax/test_data/parser/ok/0068_item_modifiers.rs
+++ b/crates/syntax/test_data/parser/ok/0068_item_modifiers.rs
@@ -14,3 +14,5 @@ unsafe auto trait T {}
 unsafe impl Foo {}
 default impl Foo {}
 unsafe default impl Foo {}
+
+unsafe extern "C++" {}
-- 
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