From 1c1b4f76bd2a6ef5cb64eaec4b4d56f76c88c292 Mon Sep 17 00:00:00 2001
From: topecongiro <seuchida@gmail.com>
Date: Tue, 28 May 2019 00:03:42 +0900
Subject: [PATCH 1/3] Add a test for #3583

---
 tests/source/macros.rs | 3 +++
 tests/target/macros.rs | 3 +++
 2 files changed, 6 insertions(+)

diff --git a/tests/source/macros.rs b/tests/source/macros.rs
index 66012e4d69d4d..ef5b1efa5b967 100644
--- a/tests/source/macros.rs
+++ b/tests/source/macros.rs
@@ -475,3 +475,6 @@ pub fn fold_abi<V: Fold + ?Sized>(_visitor: &mut V, _i: Abi) -> Abi {
 // #3463
 x ! {()}
 x ! y {()}
+
+// #3583
+foo!(|x = y|);
diff --git a/tests/target/macros.rs b/tests/target/macros.rs
index 8f86b79f9225e..f19b5d11feef7 100644
--- a/tests/target/macros.rs
+++ b/tests/target/macros.rs
@@ -1052,3 +1052,6 @@ pub fn fold_abi<V: Fold + ?Sized>(_visitor: &mut V, _i: Abi) -> Abi {
 // #3463
 x! {()}
 x! y {()}
+
+// #3583
+foo!(|x = y|);

From f7cd789ebc135cb165f00e64a7e5edaf821c0c62 Mon Sep 17 00:00:00 2001
From: topecongiro <seuchida@gmail.com>
Date: Tue, 28 May 2019 00:03:50 +0900
Subject: [PATCH 2/3] Catch panics from the parser while rewriting macro calls

---
 src/macros.rs | 32 ++++++++++++++++++--------------
 1 file changed, 18 insertions(+), 14 deletions(-)

diff --git a/src/macros.rs b/src/macros.rs
index a42b839f9c507..d25106c49616e 100644
--- a/src/macros.rs
+++ b/src/macros.rs
@@ -10,6 +10,7 @@
 // and those with brackets will be formatted as array literals.
 
 use std::collections::HashMap;
+use std::panic::{catch_unwind, AssertUnwindSafe};
 
 use syntax::parse::new_parser_from_tts;
 use syntax::parse::parser::Parser;
@@ -208,21 +209,24 @@ pub(crate) fn rewrite_macro(
     shape: Shape,
     position: MacroPosition,
 ) -> Option<String> {
-    let should_skip = context
-        .skip_macro_names
-        .borrow()
-        .contains(&context.snippet(mac.node.path.span).to_owned());
-    if should_skip {
-        None
-    } else {
-        let guard = InsideMacroGuard::inside_macro_context(context);
-        let result =
-            rewrite_macro_inner(mac, extra_ident, context, shape, position, guard.is_nested);
-        if result.is_none() {
-            context.macro_rewrite_failure.replace(true);
+    catch_unwind(AssertUnwindSafe(|| {
+        let should_skip = context
+            .skip_macro_names
+            .borrow()
+            .contains(&context.snippet(mac.node.path.span).to_owned());
+        if should_skip {
+            None
+        } else {
+            let guard = InsideMacroGuard::inside_macro_context(context);
+            let result =
+                rewrite_macro_inner(mac, extra_ident, context, shape, position, guard.is_nested);
+            if result.is_none() {
+                context.macro_rewrite_failure.replace(true);
+            }
+            result
         }
-        result
-    }
+    }))
+    .ok()?
 }
 
 fn check_keyword<'a, 'b: 'a>(parser: &'a mut Parser<'b>) -> Option<MacroArg> {

From 36dd49ae5f4fd0e0d54111533f1577fccfef979a Mon Sep 17 00:00:00 2001
From: topecongiro <seuchida@gmail.com>
Date: Tue, 28 May 2019 00:14:36 +0900
Subject: [PATCH 3/3] Set macro_rewrite_failure to true on catching panic

---
 src/macros.rs | 31 ++++++++++++++++---------------
 1 file changed, 16 insertions(+), 15 deletions(-)

diff --git a/src/macros.rs b/src/macros.rs
index d25106c49616e..077e6a32d62c8 100644
--- a/src/macros.rs
+++ b/src/macros.rs
@@ -209,24 +209,25 @@ pub(crate) fn rewrite_macro(
     shape: Shape,
     position: MacroPosition,
 ) -> Option<String> {
-    catch_unwind(AssertUnwindSafe(|| {
-        let should_skip = context
-            .skip_macro_names
-            .borrow()
-            .contains(&context.snippet(mac.node.path.span).to_owned());
-        if should_skip {
-            None
-        } else {
-            let guard = InsideMacroGuard::inside_macro_context(context);
-            let result =
-                rewrite_macro_inner(mac, extra_ident, context, shape, position, guard.is_nested);
-            if result.is_none() {
+    let should_skip = context
+        .skip_macro_names
+        .borrow()
+        .contains(&context.snippet(mac.node.path.span).to_owned());
+    if should_skip {
+        None
+    } else {
+        let guard = InsideMacroGuard::inside_macro_context(context);
+        let result = catch_unwind(AssertUnwindSafe(|| {
+            rewrite_macro_inner(mac, extra_ident, context, shape, position, guard.is_nested)
+        }));
+        match result {
+            Err(..) | Ok(None) => {
                 context.macro_rewrite_failure.replace(true);
+                None
             }
-            result
+            Ok(rw) => rw,
         }
-    }))
-    .ok()?
+    }
 }
 
 fn check_keyword<'a, 'b: 'a>(parser: &'a mut Parser<'b>) -> Option<MacroArg> {