@@ -44,6 +44,8 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
4444 candidate : & mut Candidate < ' pat , ' tcx > ,
4545 ) -> bool {
4646 // repeatedly simplify match pairs until fixed point is reached
47+ debug ! ( "simplify_candidate(candidate={:?})" , candidate) ;
48+ let mut new_bindings = Vec :: new ( ) ;
4749 loop {
4850 let match_pairs = mem:: take ( & mut candidate. match_pairs ) ;
4951
@@ -56,7 +58,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
5658
5759 let mut changed = false ;
5860 for match_pair in match_pairs {
59- match self . simplify_match_pair ( match_pair, candidate) {
61+ match self . simplify_match_pair ( match_pair, candidate, & mut new_bindings ) {
6062 Ok ( ( ) ) => {
6163 changed = true ;
6264 }
@@ -65,13 +67,31 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
6567 }
6668 }
6769 }
70+ // issue #69971: the binding order should be right to left if there are more
71+ // bindings after `@` to please the borrow checker
72+ // Ex
73+ // struct NonCopyStruct {
74+ // copy_field: u32,
75+ // }
76+ //
77+ // fn foo1(x: NonCopyStruct) {
78+ // let y @ NonCopyStruct { copy_field: z } = x;
79+ // // the above should turn into
80+ // let z = x.copy_field;
81+ // let y = x;
82+ // }
83+ new_bindings. extend_from_slice ( & candidate. bindings ) ;
84+ mem:: swap ( & mut candidate. bindings , & mut new_bindings) ;
85+ new_bindings. clear ( ) ;
86+
6887 if !changed {
6988 // Move or-patterns to the end, because they can result in us
7089 // creating additional candidates, so we want to test them as
7190 // late as possible.
7291 candidate
7392 . match_pairs
7493 . sort_by_key ( |pair| matches ! ( * pair. pattern. kind, PatKind :: Or { .. } ) ) ;
94+ debug ! ( "simplify_candidate: simplifed {:?}" , candidate) ;
7595 return false ; // if we were not able to simplify any, done.
7696 }
7797 }
@@ -104,6 +124,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
104124 & mut self ,
105125 match_pair : MatchPair < ' pat , ' tcx > ,
106126 candidate : & mut Candidate < ' pat , ' tcx > ,
127+ bindings : & mut Vec < Binding < ' tcx > > ,
107128 ) -> Result < ( ) , MatchPair < ' pat , ' tcx > > {
108129 let tcx = self . hir . tcx ( ) ;
109130 match * match_pair. pattern . kind {
@@ -131,20 +152,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
131152 }
132153
133154 PatKind :: Binding { name, mutability, mode, var, ty, ref subpattern, is_primary : _ } => {
134- // issue #69971: the binding order should be right to left if there are more
135- // bindings after `@` to please the borrow checker
136- // Ex
137- // struct NonCopyStruct {
138- // copy_field: u32,
139- // }
140- //
141- // fn foo1(x: NonCopyStruct) {
142- // let y @ NonCopyStruct { copy_field: z } = x;
143- // // the above should turn into
144- // let z = x.copy_field;
145- // let y = x;
146- // }
147- candidate. bindings . insert ( 0 , Binding {
155+ bindings. push ( Binding {
148156 name,
149157 mutability,
150158 span : match_pair. pattern . span ,
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