Handle negative literal const generic argument after left arrow

dtolnay · Feb 19, 2022 · c38e117 · c38e117
1 parent c36c0fd
commit c38e117
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Showing 2 changed files with 17 additions and 1 deletion.
diff --git a/src/ensure.rs b/src/ensure.rs
@@ -257,6 +257,10 @@ macro_rules! __parse_ensure {
         $crate::__parse_ensure!(generic (epath $stack) $bail ($($fuel)*) {($($buf)* $colons <) $($parse)*} (< $($rest)*) < $($rest)*)
     };
 
+    (epath $stack:tt $bail:tt (~$($fuel:tt)*) {($($buf:tt)*) $($parse:tt)*} ($colons:tt $($dup:tt)*) :: <- $($rest:tt)*) => {
+        $crate::__parse_ensure!(generic (epath $stack) $bail ($($fuel)*) {($($buf)* $colons <) $($parse)*} (- $($rest)*) - $($rest)*)
+    };
+
     (epath $stack:tt $bail:tt (~$($fuel:tt)*) {($($buf:tt)*) $($parse:tt)*} ($colons:tt $($dup:tt)*) :: $ident:ident $($rest:tt)*) => {
         $crate::__parse_ensure!(epath $stack $bail ($($fuel)*) {($($buf)* $colons $ident) $($parse)*} ($($rest)*) $($rest)*)
     };
@@ -303,6 +307,10 @@ macro_rules! __parse_ensure {
         $crate::__parse_ensure!(generic (atom $stack) $bail ($($fuel)*) {($($buf)* $dot $ident $colons <) $($parse)*} (< $($rest)*) < $($rest)*)
     };
 
+    (atom $stack:tt $bail:tt (~$($fuel:tt)*) {($($buf:tt)*) $($parse:tt)*} ($dot:tt $ident:tt $colons:tt $($dup:tt)*) . $i:ident :: <- $($rest:tt)*) => {
+        $crate::__parse_ensure!(generic (atom $stack) $bail ($($fuel)*) {($($buf)* $dot $ident $colons <) $($parse)*} (- $($rest)*) - $($rest)*)
+    };
+
     (atom $stack:tt $bail:tt (~$($fuel:tt)*) {($($buf:tt)*) $($parse:tt)*} ($dot:tt $($dup:tt)*) . $field:ident $($rest:tt)*) => {
         $crate::__parse_ensure!(atom $stack $bail ($($fuel)*) {($($buf)* $dot $field) $($parse)*} ($($rest)*) $($rest)*)
     };
@@ -427,6 +435,10 @@ macro_rules! __parse_ensure {
         $crate::__parse_ensure!(generic (tpath $stack) $bail ($($fuel)*) {($($buf)* <) $($parse)*} (< $($rest)*) < $($rest)*)
     };
 
+    (tpath $stack:tt $bail:tt (~$($fuel:tt)*) {($($buf:tt)*) $($parse:tt)*} $dup:tt <- $($rest:tt)*) => {
+        $crate::__parse_ensure!(generic (tpath $stack) $bail ($($fuel)*) {($($buf)* <) $($parse)*} (- $($rest)*) - $($rest)*)
+    };
+
     (tpath $stack:tt $bail:tt (~$($fuel:tt)*) {($($buf:tt)*) $($parse:tt)*} ($colons:tt $langle:tt $($dup:tt)*) :: < $($rest:tt)*) => {
         $crate::__parse_ensure!(generic (tpath $stack) $bail ($($fuel)*) {($($buf)* $colons $langle) $($parse)*} ($($rest)*) $($rest)*)
     };
@@ -435,6 +447,10 @@ macro_rules! __parse_ensure {
         $crate::__parse_ensure!(generic (tpath $stack) $bail ($($fuel)*) {($($buf)* $colons <) $($parse)*} (< $($rest)*) < $($rest)*)
     };
 
+    (tpath $stack:tt $bail:tt (~$($fuel:tt)*) {($($buf:tt)*) $($parse:tt)*} ($colons:tt $($dup:tt)*) :: <- $($rest:tt)*) => {
+        $crate::__parse_ensure!(generic (tpath $stack) $bail ($($fuel)*) {($($buf)* $colons <) $($parse)*} (- $($rest)*) - $($rest)*)
+    };
+
     (tpath $stack:tt $bail:tt (~$($fuel:tt)*) {($($buf:tt)*) $($parse:tt)*} ($colons:tt $($dup:tt)*) :: $ident:ident $($rest:tt)*) => {
         $crate::__parse_ensure!(tpath $stack $bail ($($fuel)*) {($($buf)* $colons $ident) $($parse)*} ($($rest)*) $($rest)*)
     };

diff --git a/tests/test_ensure.rs b/tests/test_ensure.rs
@@ -328,7 +328,7 @@ fn test_path() {
     let test = || Ok(ensure!(f::<1>() != ()));
     assert_err(test, "Condition failed: `f::<1>() != ()` (() vs ())");
     let test = || Ok(ensure!(f::<-1>() != ()));
-    assert_err(test, "Condition failed: `f::<-1>() != ()`"); // FIXME
+    assert_err(test, "Condition failed: `f::<-1>() != ()` (() vs ())");
 
     fn g<T, const I: isize>() {}
     let test = || Ok(ensure!(g::<u8, 1>() != ()));