Propagate coercion cause into try_coerce
#89028
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Currently, `coerce_inner` discards its `ObligationCause` when calling `try_coerce`. This interfers with other diagnostc improvements I'm working on, since we will lose the original span by the time the actual coercion occurs. Additionally, we now use the span of the trailing expression (rather than the span of the entire function) when performing a coercion in `check_return_expr`. This currently has no visible effect on any of the unit tests, but will unblock future diagnostic improvements.
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@bors try @rust-timer queue inference perf can easily be regressed by innocent changes, let's check that first |
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Awaiting bors try build completion. @rustbot label: +S-waiting-on-perf |
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⌛ Trying commit 31cdd8c with merge 9a02d2019558beb5eb9dcb801d3d4e86ea21c3b4... |
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☀️ Try build successful - checks-actions |
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Queued 9a02d2019558beb5eb9dcb801d3d4e86ea21c3b4 with parent 78a46ef, future comparison URL. |
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Finished benchmarking commit (9a02d2019558beb5eb9dcb801d3d4e86ea21c3b4): comparison url. Summary: This benchmark run did not return any relevant changes. If you disagree with this performance assessment, please file an issue in rust-lang/rustc-perf. Benchmarking this pull request likely means that it is perf-sensitive, so we're automatically marking it as not fit for rolling up. While you can manually mark this PR as fit for rollup, we strongly recommend not doing so since this PR led to changes in compiler perf. @bors rollup=never |
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| let mut span = return_expr.span; | ||
| // Use the span of the trailing expression for our cause, | ||
| // not the span of the entire function | ||
| if !explicit_return { |
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Is it actually necessary to have the boolean flag here? I imagine it is trying to account for something like
return { foo; bar; baz };
so that rustc would span the entire block and not just baz here? It seems to me that it would be actually better, and more consistent if we spanned the last expression of the block in these situations.
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@bors r+ |
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📌 Commit 31cdd8c has been approved by |
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☀️ Test successful - checks-actions |
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Finished benchmarking commit (3bca723): comparison url. Summary: This benchmark run did not return any relevant changes. If you disagree with this performance assessment, please file an issue in rust-lang/rustc-perf. @rustbot label: -perf-regression |
Currently,
coerce_innerdiscards itsObligationCausewhen calling
try_coerce. This interfers with otherdiagnostc improvements I'm working on, since we will lose
the original span by the time the actual coercion occurs.
Additionally, we now use the span of the trailing expression
(rather than the span of the entire function) when performing
a coercion in
check_return_expr. This currently has no visibleeffect on any of the unit tests, but will unblock future
diagnostic improvements.