reduce false positives of tail-expr-drop-order from consumed values

take 2

open up coroutines

tweak the wordings

the lint works up until 2021

We were missing one case, for ADTs, which was
causing `Result` to yield incorrect results.

only include field spans with significant types

deduplicate and eliminate field spans

switch to emit spans to impl Drops

Co-authored-by: Niko Matsakis <nikomat@amazon.com>

collect drops instead of taking liveness diff

apply some suggestions and add explantory notes

small fix on the cache

let the query recurse through coroutine

new suggestion format with extracted variable name

fine-tune the drop span and messages

bugfix on runtime borrows

tweak message wording

filter out ecosystem types earlier

apply suggestions

clippy

check lint level at session level

further restrict applicability of the lint

translate bid into nop for stable mir

detect cycle in type structure

1 files changed, 7 insertions, 11 deletions

diff --git a/compiler/rustc_mir_build/src/build/expr/into.rs b/compiler/rustc_mir_build/src/build/expr/into.rs
index 0dec56d21ae..bebb44faba6 100644
--- a/compiler/rustc_mir_build/src/build/expr/into.rs
+++ b/compiler/rustc_mir_build/src/build/expr/into.rs
@@ -139,7 +139,8 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                 // (#66975) Source could be a const of type `!`, so has to
                 // exist in the generated MIR.
                 unpack!(
-                    block = this.as_temp(block, Some(this.local_scope()), source, Mutability::Mut)
+                    block =
+                        this.as_temp(block, this.local_temp_lifetime(), source, Mutability::Mut)
                 );
 
                 // This is an optimization. If the expression was a call then we already have an
@@ -321,7 +322,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                 let is_union = adt_def.is_union();
                 let active_field_index = is_union.then(|| fields[0].name);
 
-                let scope = this.local_scope();
+                let scope = this.local_temp_lifetime();
 
                 // first process the set of fields that were provided
                 // (evaluating them in order given by user)
@@ -333,7 +334,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                             unpack!(
                                 block = this.as_operand(
                                     block,
-                                    Some(scope),
+                                    scope,
                                     f.expr,
                                     LocalInfo::AggregateTemp,
                                     NeedsTemporary::Maybe,
@@ -548,15 +549,10 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
             }
 
             ExprKind::Yield { value } => {
-                let scope = this.local_scope();
+                let scope = this.local_temp_lifetime();
                 let value = unpack!(
-                    block = this.as_operand(
-                        block,
-                        Some(scope),
-                        value,
-                        LocalInfo::Boring,
-                        NeedsTemporary::No
-                    )
+                    block =
+                        this.as_operand(block, scope, value, LocalInfo::Boring, NeedsTemporary::No)
                 );
                 let resume = this.cfg.start_new_block();
                 this.cfg.terminate(block, source_info, TerminatorKind::Yield {