From 04732a7cf3be706f9a4bcaf40cc4f47dd0821d9c Mon Sep 17 00:00:00 2001
From: David Tolnay <dtolnay@gmail.com>
Date: Sat, 27 Nov 2021 12:00:02 -0800
Subject: [PATCH] Parse trait object types

---
 src/ensure.rs        | 26 ++++++++++++++++++++------
 tests/test_ensure.rs | 23 +++++++++++++++++++++++
 2 files changed, 43 insertions(+), 6 deletions(-)

diff --git a/src/ensure.rs b/src/ensure.rs
index cd2f901..026e6b1 100644
--- a/src/ensure.rs
+++ b/src/ensure.rs
@@ -443,16 +443,16 @@ macro_rules! __parse_ensure {
         $crate::__parse_ensure!(type $stack $bail ($($fuel)*) {($($buf)* $paren $arrow) $($parse)*} ($($rest)*) $($rest)*)
     };
 
-    (tpath ($pop:ident $stack:tt) $bail:tt (~$($fuel:tt)*) {($($buf:tt)*) $($parse:tt)*} ($paren:tt $($dup:tt)*) ($($args:tt)*) $($rest:tt)*) => {
-        $crate::__parse_ensure!($pop $stack $bail ($($fuel)*) {($($buf)* $paren) $($parse)*} ($($rest)*) $($rest)*)
+    (tpath $stack:tt $bail:tt (~$($fuel:tt)*) {($($buf:tt)*) $($parse:tt)*} ($paren:tt $($dup:tt)*) ($($args:tt)*) $($rest:tt)*) => {
+        $crate::__parse_ensure!(object $stack $bail ($($fuel)*) {($($buf)* $paren) $($parse)*} ($($rest)*) $($rest)*)
     };
 
     (tpath $stack:tt $bail:tt (~$($fuel:tt)*) {($($buf:tt)*) $($parse:tt)*} ($colons:tt $paren:tt $arrow:tt $($dup:tt)*) :: ($($args:tt)*) -> $($rest:tt)*) => {
         $crate::__parse_ensure!(type $stack $bail ($($fuel)*) {($($buf)* $colons $paren $arrow) $($parse)*} ($($rest)*) $($rest)*)
     };
 
-    (tpath ($pop:ident $stack:tt) $bail:tt (~$($fuel:tt)*) {($($buf:tt)*) $($parse:tt)*} ($colons:tt $paren:tt $($dup:tt)*) :: ($($args:tt)*) $($rest:tt)*) => {
-        $crate::__parse_ensure!($pop $stack $bail ($($fuel)*) {($($buf)* $colons $paren) $($parse)*} ($($rest)*) $($rest)*)
+    (tpath $stack:tt $bail:tt (~$($fuel:tt)*) {($($buf:tt)*) $($parse:tt)*} ($colons:tt $paren:tt $($dup:tt)*) :: ($($args:tt)*) $($rest:tt)*) => {
+        $crate::__parse_ensure!(object $stack $bail ($($fuel)*) {($($buf)* $colons $paren) $($parse)*} ($($rest)*) $($rest)*)
     };
 
     (tpath ($pop:ident $stack:tt) $bail:tt (~$($fuel:tt)*) {($($buf:tt)*) $($parse:tt)*} ($bang:tt $args:tt $($dup:tt)*) ! ($($mac:tt)*) $($rest:tt)*) => {
@@ -467,8 +467,8 @@ macro_rules! __parse_ensure {
         $crate::__parse_ensure!($pop $stack $bail ($($fuel)*) {($($buf)* $bang $args) $($parse)*} ($($rest)*) $($rest)*)
     };
 
-    (tpath ($pop:ident $stack:tt) $bail:tt (~$($fuel:tt)*) $parse:tt $dup:tt $($rest:tt)*) => {
-        $crate::__parse_ensure!($pop $stack $bail ($($fuel)*) $parse $dup $($rest)*)
+    (tpath $stack:tt $bail:tt (~$($fuel:tt)*) $parse:tt $dup:tt $($rest:tt)*) => {
+        $crate::__parse_ensure!(object $stack $bail ($($fuel)*) $parse $dup $($rest)*)
     };
 
     // qualified paths
@@ -481,6 +481,20 @@ macro_rules! __parse_ensure {
         $crate::__parse_ensure!(type (qpath $stack) $bail ($($fuel)*) {($($buf)* $as) $($parse)*} ($($rest)*) $($rest)*)
     };
 
+    // trait objects
+
+    (object (arglist $stack:tt) $bail:tt (~$($fuel:tt)*) {($($buf:tt)*) $($parse:tt)*} ($plus:tt $colons:tt $($dup:tt)*) + :: $ident:ident $($rest:tt)*) => {
+        $crate::__parse_ensure!(tpath (arglist $stack) $bail ($($fuel)*) {($($buf)* $plus $colons $ident) $($parse)*} ($($rest)*) $($rest)*)
+    };
+
+    (object (arglist $stack:tt) $bail:tt (~$($fuel:tt)*) {($($buf:tt)*) $($parse:tt)*} ($plus:tt $($dup:tt)*) + $ident:ident $($rest:tt)*) => {
+        $crate::__parse_ensure!(tpath (arglist $stack) $bail ($($fuel)*) {($($buf)* $plus $ident) $($parse)*} ($($rest)*) $($rest)*)
+    };
+
+    (object ($pop:ident $stack:tt) $bail:tt (~$($fuel:tt)*) $parse:tt $dup:tt $($rest:tt)*) => {
+        $crate::__parse_ensure!($pop $stack $bail ($($fuel)*) $parse $dup $($rest)*)
+    };
+
     // angle bracketed generic arguments
 
     (generic ($pop:ident $stack:tt) $bail:tt (~$($fuel:tt)*) {($($buf:tt)*) $($parse:tt)*} ($rangle:tt $($dup:tt)*) > $($rest:tt)*) => {
diff --git a/tests/test_ensure.rs b/tests/test_ensure.rs
index 0addcc4..be6df00 100644
--- a/tests/test_ensure.rs
+++ b/tests/test_ensure.rs
@@ -341,6 +341,29 @@ fn test_path() {
     #[rustfmt::skip]
     let test = || Ok(ensure!(E::U::<u8,>>E::U));
     assert_err(test, "Condition failed: `E::U::<u8> > E::U` (U vs U)");
+
+    let test = || Ok(ensure!(PhantomData::<dyn Debug + Sync> != PhantomData));
+    assert_err(
+        test,
+        "Condition failed: `PhantomData::<dyn Debug + Sync> != PhantomData` (PhantomData vs PhantomData)",
+    );
+
+    let test = || Ok(ensure!(PhantomData::<dyn Fn() + Sync> != PhantomData));
+    assert_err(
+        test,
+        "Condition failed: `PhantomData::<dyn Fn() + Sync> != PhantomData` (PhantomData vs PhantomData)",
+    );
+
+    #[rustfmt::skip]
+    let test = || {
+        Ok(ensure!(
+            PhantomData::<dyn Fn::() + ::std::marker::Sync> != PhantomData
+        ))
+    };
+    assert_err(
+        test,
+        "Condition failed: `PhantomData::<dyn Fn() + ::std::marker::Sync> != PhantomData` (PhantomData vs PhantomData)",
+    );
 }
 
 #[test]