From ad78d70db3da4923f4d37a4a40f7b5850ec6e52e Mon Sep 17 00:00:00 2001
From: David Tolnay <dtolnay@gmail.com>
Date: Fri, 17 May 2024 13:29:21 -0700
Subject: [PATCH] Preserve more token spans in expression parser

---
 src/ensure.rs | 68 ++++++++++++++++++++++++++++++++++++---------------
 1 file changed, 48 insertions(+), 20 deletions(-)

diff --git a/src/ensure.rs b/src/ensure.rs
index e8fe9f8..de0b95a 100644
--- a/src/ensure.rs
+++ b/src/ensure.rs
@@ -258,12 +258,12 @@ macro_rules! __parse_ensure {
         $crate::__parse_ensure!(generic (epath $stack) $bail ($($fuel)*) {($($buf)* $colons $langle) $($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)*) // FIXME
+    (epath $stack:tt $bail:tt (~$($fuel:tt)*) {($($buf:tt)*) $($parse:tt)*} ($colons:tt $langle:tt $($dup:tt)*) :: << $($rest:tt)*) => {
+        $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 $($dup:tt)*) :: <- $($rest:tt)*) => {
-        $crate::__parse_ensure!(generic (epath $stack) $bail ($($fuel)*) {($($buf)* $colons <) $($parse)*} (- $($rest)*) - $($rest)*) // FIXME
+    (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)*} ($colons:tt $ident:tt $($dup:tt)*) :: $i:ident $($rest:tt)*) => {
@@ -282,6 +282,10 @@ macro_rules! __parse_ensure {
         $crate::__parse_ensure!($pop $stack $bail ($($fuel)*) {($($buf)* $bang $args) $($parse)*} ($($rest)*) $($rest)*)
     };
 
+    (epath (split ($pop:ident $stack:tt)) $bail:tt (~$($fuel:tt)*) $parse:tt $dup:tt $($rest:tt)*) => {
+        $crate::__parse_ensure!($pop (split $stack) $bail ($($fuel)*) $parse $dup $($rest)*)
+    };
+
     (epath ($pop:ident $stack:tt) $bail:tt (~$($fuel:tt)*) $parse:tt $dup:tt $($rest:tt)*) => {
         $crate::__parse_ensure!($pop $stack $bail ($($fuel)*) $parse $dup $($rest)*)
     };
@@ -308,12 +312,12 @@ macro_rules! __parse_ensure {
         $crate::__parse_ensure!(generic (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 $($dup:tt)*) . $i:ident :: << $($rest:tt)*) => {
-        $crate::__parse_ensure!(generic (atom $stack) $bail ($($fuel)*) {($($buf)* $dot $ident $colons <) $($parse)*} (< $($rest)*) < $($rest)*) // FIXME
+    (atom $stack:tt $bail:tt (~$($fuel:tt)*) {($($buf:tt)*) $($parse:tt)*} ($dot:tt $ident:tt $colons:tt $langle:tt $($dup:tt)*) . $i:ident :: << $($rest:tt)*) => {
+        $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 $($dup:tt)*) . $i:ident :: <- $($rest:tt)*) => {
-        $crate::__parse_ensure!(generic (atom $stack) $bail ($($fuel)*) {($($buf)* $dot $ident $colons <) $($parse)*} (- $($rest)*) - $($rest)*) // FIXME
+    (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)*} ($dot:tt $field:tt $($dup:tt)*) . $i:ident $($rest:tt)*) => {
@@ -444,24 +448,24 @@ macro_rules! __parse_ensure {
         $crate::__parse_ensure!(generic (tpath $stack) $bail ($($fuel)*) {($($buf)* $langle) $($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)*) // FIXME
+    (tpath $stack:tt $bail:tt (~$($fuel:tt)*) {($($buf:tt)*) $($parse:tt)*} ($langle:tt $($dup:tt)*) << $($rest:tt)*) => {
+        $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)*} $dup:tt <- $($rest:tt)*) => {
-        $crate::__parse_ensure!(generic (tpath $stack) $bail ($($fuel)*) {($($buf)* <) $($parse)*} (- $($rest)*) - $($rest)*) // FIXME
+    (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)*} ($colons:tt $langle:tt $($dup:tt)*) :: < $($rest:tt)*) => {
         $crate::__parse_ensure!(generic (tpath $stack) $bail ($($fuel)*) {($($buf)* $colons $langle) $($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)*) // FIXME
+    (tpath $stack:tt $bail:tt (~$($fuel:tt)*) {($($buf:tt)*) $($parse:tt)*} ($colons:tt $langle:tt $($dup:tt)*) :: << $($rest:tt)*) => {
+        $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 $($dup:tt)*) :: <- $($rest:tt)*) => {
-        $crate::__parse_ensure!(generic (tpath $stack) $bail ($($fuel)*) {($($buf)* $colons <) $($parse)*} (- $($rest)*) - $($rest)*) // FIXME
+    (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)*} ($colons:tt $ident:tt $($dup:tt)*) :: $i:ident $($rest:tt)*) => {
@@ -502,6 +506,10 @@ macro_rules! __parse_ensure {
 
     // qualified paths
 
+    (qpath (split ($pop:ident $stack:tt)) $bail:tt (~$($fuel:tt)*) {($($buf:tt)*) $($parse:tt)*} ($rangle:tt $colons:tt $ident:tt $($dup:tt)*) >> :: $i:ident $($rest:tt)*) => {
+        $crate::__parse_ensure!($pop $stack $bail ($($fuel)*) {($($buf)* $rangle $colons $ident) $($parse)*} ($($rest)*) $($rest)*)
+    };
+
     (qpath ($pop:ident $stack:tt) $bail:tt (~$($fuel:tt)*) {($($buf:tt)*) $($parse:tt)*} ($rangle:tt $colons:tt $ident:tt $($dup:tt)*) > :: $i:ident $($rest:tt)*) => {
         $crate::__parse_ensure!($pop $stack $bail ($($fuel)*) {($($buf)* $rangle $colons $ident) $($parse)*} ($($rest)*) $($rest)*)
     };
@@ -520,18 +528,26 @@ macro_rules! __parse_ensure {
         $crate::__parse_ensure!(tpath (arglist $stack) $bail ($($fuel)*) {($($buf)* $plus $ident) $($parse)*} ($($rest)*) $($rest)*)
     };
 
+    (object (split ($pop:ident $stack:tt)) $bail:tt (~$($fuel:tt)*) $parse:tt $dup:tt $($rest:tt)*) => {
+        $crate::__parse_ensure!($pop (split $stack) $bail ($($fuel)*) $parse $dup $($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 (split ($pop:ident $stack:tt)) $bail:tt (~$($fuel:tt)*) {($($buf:tt)*) $($parse:tt)*} ($rangle:tt $($dup:tt)*) >> $($rest:tt)*) => {
+        $crate::__parse_ensure!($pop $stack $bail ($($fuel)*) {($($buf)* $rangle) $($parse)*} ($($rest)*) $($rest)*)
+    };
+
     (generic ($pop:ident $stack:tt) $bail:tt (~$($fuel:tt)*) {($($buf:tt)*) $($parse:tt)*} ($rangle:tt $($dup:tt)*) > $($rest:tt)*) => {
         $crate::__parse_ensure!($pop $stack $bail ($($fuel)*) {($($buf)* $rangle) $($parse)*} ($($rest)*) $($rest)*)
     };
 
-    (generic ($pop:ident $stack:tt) $bail:tt (~$($fuel:tt)*) {($($buf:tt)*) $($parse:tt)*} $dup:tt >> $($rest:tt)*) => {
-        $crate::__parse_ensure!($pop $stack $bail ($($fuel)*) {($($buf)* >) $($parse)*} (> $($rest)*) > $($rest)*) // FIXME
+    (generic ($pop:ident $stack:tt) $bail:tt (~$($fuel:tt)*) {($($buf:tt)*) $($parse:tt)*} ($rangle:tt $($dup:tt)*) >> $($rest:tt)*) => {
+        $crate::__parse_ensure!($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)*) => {
@@ -562,12 +578,16 @@ macro_rules! __parse_ensure {
         $crate::__parse_ensure!(generic $stack $bail ($($fuel)*) {($($buf)* $comma) $($parse)*} ($($rest)*) $($rest)*)
     };
 
+    (arglist (split ($pop:ident $stack:tt)) $bail:tt (~$($fuel:tt)*) {($($buf:tt)*) $($parse:tt)*} ($rangle:tt $($dup:tt)*) >> $($rest:tt)*) => {
+        $crate::__parse_ensure!($pop $stack $bail ($($fuel)*) {($($buf)*) $rangle $($parse)*} ($($rest)*) $($rest)*)
+    };
+
     (arglist ($pop:ident $stack:tt) $bail:tt (~$($fuel:tt)*) {($($buf:tt)*) $($parse:tt)*} ($rangle:tt $($dup:tt)*) > $($rest:tt)*) => {
         $crate::__parse_ensure!($pop $stack $bail ($($fuel)*) {($($buf)* $rangle) $($parse)*} ($($rest)*) $($rest)*)
     };
 
-    (arglist ($pop:ident $stack:tt) $bail:tt (~$($fuel:tt)*) {($($buf:tt)*) $($parse:tt)*} $dup:tt >> $($rest:tt)*) => {
-        $crate::__parse_ensure!($pop $stack $bail ($($fuel)*) {($($buf)* >) $($parse)*} (> $($rest)*) > $($rest)*) // FIXME
+    (arglist ($pop:ident $stack:tt) $bail:tt (~$($fuel:tt)*) {($($buf:tt)*) $($parse:tt)*} ($rangle:tt $($dup:tt)*) >> $($rest:tt)*) => {
+        $crate::__parse_ensure!($pop (split $stack) $bail ($($fuel)*) {($($buf)*) $($parse)*} ($rangle $($rest)*) $rangle $($rest)*)
     };
 
     // patterns
@@ -690,10 +710,18 @@ macro_rules! __parse_ensure {
         $crate::__parse_ensure!(0 $stack $bail ($($fuel)*) {($($buf)* $ge) $($parse)*} ($($rest)*) $($rest)*)
     };
 
+    (atom (split ()) $bail:tt (~$($fuel:tt)*) {($($buf:tt)*) $($parse:tt)*} $dup:tt >> $($rest:tt)*) => {
+        $crate::__parse_ensure!(0 () $bail ($($fuel)*) {() $($parse)* ($($buf)* > ) > } ($($rest)*) $($rest)*)
+    };
+
     (atom () $bail:tt (~$($fuel:tt)*) {($($buf:tt)*) $($parse:tt)*} ($gt:tt $($dup:tt)*) > $($rest:tt)*) => {
         $crate::__parse_ensure!(0 () $bail ($($fuel)*) {() $($parse)* ($($buf)*) $gt} ($($rest)*) $($rest)*)
     };
 
+    (atom (split $stack:tt) $bail:tt (~$($fuel:tt)*) {($($buf:tt)+) $($parse:tt)*} ($rangle:tt $($dup:tt)*) >> $($rest:tt)*) => {
+        $crate::__parse_ensure!(0 $stack $bail ($($fuel)*) {($($buf)* $rangle) $($parse)*} ($($rest)*) $($rest)*)
+    };
+
     (atom $stack:tt $bail:tt (~$($fuel:tt)*) {($($buf:tt)+) $($parse:tt)*} ($gt:tt $($dup:tt)*) > $($rest:tt)*) => {
         $crate::__parse_ensure!(0 $stack $bail ($($fuel)*) {($($buf)* $gt) $($parse)*} ($($rest)*) $($rest)*)
     };