Repository: dtolnay/anyhow (rust)

Issue:
Cannot compile when using `ensure!`
When I upgrade `anyhow` to `1.0.85`, it fails to compile our project [zino](https://github.com/zino-rs/zino).

After some struggles, I find that the latest change of `ensure` fails to compile the following code:
```rust
fn main() -> anyhow::Result<()> {
    let a = 5;
    let b = 3;
    // Can compile
    anyhow::ensure!(a <= b || (a - b) <= 10, "always true");
    // Cannot compile
    anyhow::ensure!(a <= b || a - b <= 10, "always true");
    Ok(())
}
```

Pull request description:
Fix parse error with non-literal after minus sign
Fixes #372.

Patch:
diff --git a/src/ensure.rs b/src/ensure.rs
index de0b95a..9d0a676 100644
--- a/src/ensure.rs
+++ b/src/ensure.rs
@@ -262,8 +262,12 @@ macro_rules! __parse_ensure {
         $crate::__parse_ensure!(type (qpath (tpath (arglist (epath $stack)))) $bail ($($fuel)*) {($($buf)* $colons $langle) $($parse)*} ($($rest)*) $($rest)*)
     };
 
-    (epath $stack:tt $bail:tt (~$($fuel:tt)*) {($($buf:tt)*) $($parse:tt)*} ($colons:tt $larrow:tt $lit:literal $($dup:tt)*) :: <- $($rest:tt)*) => {
-        $crate::__parse_ensure!(generic (epath $stack) $bail ($($fuel)*) {($($buf)* $colons $larrow) $($parse)*} ($($rest)*) $($rest)*)
+    (epath $stack:tt ($($bail:tt)*) (~$($fuel:tt)*) {($($buf:tt)*) $($parse:tt)*} $dup:tt :: <- - $($rest:tt)*) => {
+        $crate::__fallback_ensure!($($bail)*)
+    };
+
+    (epath $stack:tt $bail:tt (~$($fuel:tt)*) {($($buf:tt)*) $($parse:tt)*} ($colons:tt $larrow:tt $($dup:tt)*) :: <- $lit:literal $($rest:tt)*) => {
+        $crate::__parse_ensure!(generic (epath $stack) $bail ($($fuel)*) {($($buf)* $colons $larrow) $($parse)*} ($($dup)*) $($dup)*)
     };
 
     (epath $stack:tt $bail:tt (~$($fuel:tt)*) {($($buf:tt)*) $($parse:tt)*} ($colons:tt $ident:tt $($dup:tt)*) :: $i:ident $($rest:tt)*) => {
@@ -316,15 +320,19 @@ macro_rules! __parse_ensure {
         $crate::__parse_ensure!(type (qpath (tpath (arglist (atom $stack)))) $bail ($($fuel)*) {($($buf)* $dot $ident $colons $langle) $($parse)*} ($($rest)*) $($rest)*)
     };
 
-    (atom $stack:tt $bail:tt (~$($fuel:tt)*) {($($buf:tt)*) $($parse:tt)*} ($dot:tt $ident:tt $colons:tt $larrow:tt $lit:literal $($dup:tt)*) . $i:ident :: <- $($rest:tt)*) => {
-        $crate::__parse_ensure!(generic (atom $stack) $bail ($($fuel)*) {($($buf)* $dot $ident $colons $larrow) $($parse)*} ($($rest)*) $($rest)*)
+    (atom $stack:tt ($($bail:tt)*) (~$($fuel:tt)*) {($($buf:tt)*) $($parse:tt)*} $dup:tt . $i:ident :: <- - $($rest:tt)*) => {
+        $crate::__fallback_ensure!($($bail)*)
+    };
+
+    (atom $stack:tt $bail:tt (~$($fuel:tt)*) {($($buf:tt)*) $($parse:tt)*} ($dot:tt $ident:tt $colons:tt $larrow:tt $($dup:tt)*) . $i:ident :: <- $lit:literal $($rest:tt)*) => {
+        $crate::__parse_ensure!(generic (atom $stack) $bail ($($fuel)*) {($($buf)* $dot $ident $colons $larrow) $($parse)*} ($($dup)*) $($dup)*)
     };
 
     (atom $stack:tt $bail:tt (~$($fuel:tt)*) {($($buf:tt)*) $($parse:tt)*} ($dot:tt $field:tt $($dup:tt)*) . $i:ident $($rest:tt)*) => {
         $crate::__parse_ensure!(atom $stack $bail ($($fuel)*) {($($buf)* $dot $field) $($parse)*} ($($rest)*) $($rest)*)
     };
 
-    (atom $stack:tt ($($bail:tt)*) (~$($fuel:tt)*) {($($buf:tt)*) $($parse:tt)*} $dup:tt . - $lit:literal $($rest:tt)*) => {
+    (atom $stack:tt ($($bail:tt)*) (~$($fuel:tt)*) {($($buf:tt)*) $($parse:tt)*} $dup:tt . - $($rest:tt)*) => {
         $crate::__fallback_ensure!($($bail)*)
     };
 
@@ -386,11 +394,15 @@ macro_rules! __parse_ensure {
         $crate::__parse_ensure!(type $stack $bail ($($fuel)*) {($($buf)* $and) $($parse)*} ($($rest)*) $($rest)*)
     };
 
+    (type $stack:tt ($($bail:tt)*) (~$($fuel:tt)*) {($($buf:tt)*) $($parse:tt)*} $dup:tt unsafe extern - $($rest:tt)*) => {
+        $crate::__fallback_ensure!($($bail)*)
+    };
+
     (type $stack:tt $bail:tt (~$($fuel:tt)*) {($($buf:tt)*) $($parse:tt)*} ($unsafe:tt $(extern $($abi:literal)?)? fn $($dup:tt)*) unsafe $($rest:tt)*) => {
         $crate::__parse_ensure!(type $stack $bail ($($fuel)*) {($($buf)* $unsafe) $($parse)*} ($($rest)*) $($rest)*)
     };
 
-    (type $stack:tt ($($bail:tt)*) (~$($fuel:tt)*) {($($buf:tt)*) $($parse:tt)*} $dup:tt extern - $lit:literal $($rest:tt)*) => {
+    (type $stack:tt ($($bail:tt)*) (~$($fuel:tt)*) {($($buf:tt)*) $($parse:tt)*} $dup:tt extern - $($rest:tt)*) => {
         $crate::__fallback_ensure!($($bail)*)
     };
 
@@ -452,8 +464,12 @@ macro_rules! __parse_ensure {
         $crate::__parse_ensure!(type (qpath (tpath (arglist (tpath $stack)))) $bail ($($fuel)*) {($($buf)* $langle) $($parse)*} ($($rest)*) $($rest)*)
     };
 
-    (tpath $stack:tt $bail:tt (~$($fuel:tt)*) {($($buf:tt)*) $($parse:tt)*} ($larrow:tt $lit:literal $($dup:tt)*) <- $($rest:tt)*) => {
-        $crate::__parse_ensure!(generic (tpath $stack) $bail ($($fuel)*) {($($buf)* $larrow) $($parse)*} ($($rest)*) $($rest)*)
+    (tpath $stack:tt ($($bail:tt)*) (~$($fuel:tt)*) {($($buf:tt)*) $($parse:tt)*} $dup:tt <- - $($rest:tt)*) => {
+        $crate::__fallback_ensure!($($bail)*)
+    };
+
+    (tpath $stack:tt $bail:tt (~$($fuel:tt)*) {($($buf:tt)*) $($parse:tt)*} ($larrow:tt $($dup:tt)*) <- $lit:literal $($rest:tt)*) => {
+        $crate::__parse_ensure!(generic (tpath $stack) $bail ($($fuel)*) {($($buf)* $larrow) $($parse)*} ($($dup)*) $($dup)*)
     };
 
     (tpath $stack:tt $bail:tt (~$($fuel:tt)*) {($($buf:tt)*) $($parse:tt)*} ($colons:tt $langle:tt $($dup:tt)*) :: < $($rest:tt)*) => {
@@ -464,8 +480,12 @@ macro_rules! __parse_ensure {
         $crate::__parse_ensure!(type (qpath (tpath (arglist (tpath $stack)))) $bail ($($fuel)*) {($($buf)* $colons $langle) $($parse)*} ($($rest)*) $($rest)*)
     };
 
-    (tpath $stack:tt $bail:tt (~$($fuel:tt)*) {($($buf:tt)*) $($parse:tt)*} ($colons:tt $larrow:tt $lit:literal $($dup:tt)*) :: <- $($rest:tt)*) => {
-        $crate::__parse_ensure!(generic (tpath $stack) $bail ($($fuel)*) {($($buf)* $colons $larrow) $($parse)*} ($($rest)*) $($rest)*)
+    (tpath $stack:tt ($($bail:tt)*) (~$($fuel:tt)*) {($($buf:tt)*) $($parse:tt)*} $dup:tt :: <- - $($rest:tt)*) => {
+        $crate::__fallback_ensure!($($bail)*)
+    };
+
+    (tpath $stack:tt $bail:tt (~$($fuel:tt)*) {($($buf:tt)*) $($parse:tt)*} ($colons:tt $larrow:tt $($dup:tt)*) :: <- $lit:literal $($rest:tt)*) => {
+        $crate::__parse_ensure!(generic (tpath $stack) $bail ($($fuel)*) {($($buf)* $colons $larrow) $($parse)*} ($($dup)*) $($dup)*)
     };
 
     (tpath $stack:tt $bail:tt (~$($fuel:tt)*) {($($buf:tt)*) $($parse:tt)*} ($colons:tt $ident:tt $($dup:tt)*) :: $i:ident $($rest:tt)*) => {
@@ -550,8 +570,16 @@ macro_rules! __parse_ensure {
         $crate::__parse_ensure!($pop (split $stack) $bail ($($fuel)*) {($($buf)*) $($parse)*} ($rangle $($rest)*) $rangle $($rest)*)
     };
 
-    (generic $stack:tt $bail:tt (~$($fuel:tt)*) {($($buf:tt)*) $($parse:tt)*} ($neg:tt $lit:literal $($dup:tt)*) - $($rest:tt)*) => {
-        $crate::__parse_ensure!(generic $stack $bail ($($fuel)*) {($($buf)* $neg) $($parse)*} ($($rest)*) $($rest)*)
+    (generic $stack:tt ($($bail:tt)*) (~$($fuel:tt)*) {($($buf:tt)*) $($parse:tt)*} $dup:tt - - $($rest:tt)*) => {
+        $crate::__fallback_ensure!($($bail)*)
+    };
+
+    (generic $stack:tt $bail:tt (~$($fuel:tt)*) {($($buf:tt)*) $($parse:tt)*} ($neg:tt $($dup:tt)*) - $lit:literal $($rest:tt)*) => {
+        $crate::__parse_ensure!(generic $stack $bail ($($fuel)*) {($($buf)* $neg) $($parse)*} ($($dup)*) $($dup)*)
+    };
+
+    (generic $stack:tt ($($bail:tt)*) (~$($fuel:tt)*) {($($buf:tt)*) $($parse:tt)*} $dup:tt - $($rest:tt)*) => {
+        $crate::__fallback_ensure!($($bail)*)
     };
 
     (generic $stack:tt $bail:tt (~$($fuel:tt)*) {($($buf:tt)*) $($parse:tt)*} ($literal:tt $($dup:tt)*) $lit:literal $($rest:tt)*) => {
@@ -616,8 +644,16 @@ macro_rules! __parse_ensure {
         $crate::__parse_ensure!(pat $stack $bail ($($fuel)*) {($($buf)* $at) $($parse)*} ($($rest)*) $($rest)*)
     };
 
-    (pat $stack:tt $bail:tt (~$($fuel:tt)*) {($($buf:tt)*) $($parse:tt)*} ($neg:tt $lit:literal $($dup:tt)*) - $($rest:tt)*) => {
-        $crate::__parse_ensure!(pat $stack $bail ($($fuel)*) {($($buf)* $neg) $($parse)*} ($($rest)*) $($rest)*)
+    (pat $stack:tt ($($bail:tt)*) (~$($fuel:tt)*) {($($buf:tt)*) $($parse:tt)*} $dup:tt - - $($rest:tt)*) => {
+        $crate::__fallback_ensure!($($bail)*)
+    };
+
+    (pat $stack:tt $bail:tt (~$($fuel:tt)*) {($($buf:tt)*) $($parse:tt)*} ($neg:tt $($dup:tt)*) - $lit:literal $($rest:tt)*) => {
+        $crate::__parse_ensure!(pat $stack $bail ($($fuel)*) {($($buf)* $neg) $($parse)*} ($($dup)*) $($dup)*)
+    };
+
+    (pat $stack:tt ($($bail:tt)*) (~$($fuel:tt)*) {($($buf:tt)*) $($parse:tt)*} $dup:tt - $($rest:tt)*) => {
+        $crate::__fallback_ensure!($($bail)*)
     };
 
     (pat $stack:tt $bail:tt (~$($fuel:tt)*) {($($buf:tt)*) $($parse:tt)*} ($literal:tt $($dup:tt)*) $lit:literal $($rest:tt)*) => {


Test patch:
diff --git a/tests/test_ensure.rs b/tests/test_ensure.rs
index ee7011c..96c236d 100644
--- a/tests/test_ensure.rs
+++ b/tests/test_ensure.rs
@@ -132,6 +132,19 @@ fn test_low_precedence_binary_operator() {
         test,
         "Condition failed: `while false == true && false {} < ()` (() vs ())",
     );
+
+    let a = 15;
+    let b = 3;
+    let test = || Ok(ensure!(a <= b || a - b <= 10));
+    assert_err(test, "Condition failed: `a <= b || a - b <= 10`");
+}
+
+#[test]
+fn test_high_precedence_binary_operator() {
+    let a = 15;
+    let b = 3;
+    let test = || Ok(ensure!(a - b <= 10));
+    assert_err(test, "Condition failed: `a - b <= 10` (12 vs 10)");
 }
 
 #[test]