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Address some code reviews
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@JohnTitor
JohnTitor committed Nov 2, 2020
1 parent ad978e5 commit 66226ca
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Showing 3 changed files with 89 additions and 110 deletions.
179 changes: 85 additions & 94 deletions compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs
View file
Expand Up @@ -1570,99 +1570,66 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
format!("does not implement `{}`", trait_ref.print_only_trait_path())
};

let mut explain_yield =
|interior_span: Span, yield_span: Span, scope_span: Option<Span>| {
let mut span = MultiSpan::from_span(yield_span);
if let Ok(snippet) = source_map.span_to_snippet(interior_span) {
// #70935: If snippet contains newlines, display "the value" instead
// so that we do not emit complex diagnostics.
let snippet = &format!("`{}`", snippet);
let snippet = if snippet.contains('\n') { "the value" } else { snippet };
// The multispan can be complex here, like:
// note: future is not `Send` as this value is used across an await
// --> $DIR/issue-70935-complex-spans.rs:13:9
// |
// LL | baz(|| async{
// | __________^___-
// | | _________|
// | ||
// LL | || foo(tx.clone());
// LL | || }).await;
// | || - ^- value is later dropped here
// | ||_________|______|
// | |__________| await occurs here, with value maybe used later
// | has type `closure` which is not `Send`
// = note: the return type of a function must have a statically known size
// So, detect it and separate into some notes, like:
// note: future is not `Send` as this value is used across an await
// --> $DIR/issue-70935-complex-spans.rs:13:9
// |
// LL | / baz(|| async{
// LL | | foo(tx.clone());
// LL | | }).await;
// | |________________^
// note: first, await occurs here, with the value maybe used later
// --> $DIR/issue-70935-complex-spans.rs:13:9
// |
// LL | / baz(|| async{
// LL | | foo(tx.clone());
// LL | | }).await;
// | |________________^
// note: ...but, the value is later dropped here
// --> $DIR/issue-70935-complex-spans.rs:15:17
// |
// LL | }).await;
// | ^
// = note: the return type of a function must have a statically known size

// If available, use the scope span to annotate the drop location.
if let Some(scope_span) = scope_span {
let scope_span = source_map.end_point(scope_span);
let is_overlapped =
yield_span.overlaps(scope_span) || yield_span.overlaps(interior_span);
if is_overlapped {
err.span_note(
span,
&format!(
"{} {} as this value is used across {}",
future_or_generator, trait_explanation, an_await_or_yield
),
);
err.span_note(
yield_span,
&format!(
"first, {} occurs here, with {} maybe used later",
await_or_yield, snippet
),
);
err.span_note(
scope_span,
&format!("...but, {} is later dropped here", snippet),
);
} else {
span.push_span_label(
yield_span,
format!(
"{} occurs here, with {} maybe used later",
await_or_yield, snippet
),
);
span.push_span_label(
scope_span,
format!("{} is later dropped here", snippet),
);
span.push_span_label(
interior_span,
format!("has type `{}` which {}", target_ty, trait_explanation),
);
err.span_note(
span,
&format!(
"{} {} as this value is used across {}",
future_or_generator, trait_explanation, an_await_or_yield
),
);
}
let mut explain_yield = |interior_span: Span,
yield_span: Span,
scope_span: Option<Span>| {
let mut span = MultiSpan::from_span(yield_span);
if let Ok(snippet) = source_map.span_to_snippet(interior_span) {
// #70935: If snippet contains newlines, display "the value" instead
// so that we do not emit complex diagnostics.
let snippet = &format!("`{}`", snippet);
let snippet = if snippet.contains('\n') { "the value" } else { snippet };
// The multispan can be complex here, like:
// note: future is not `Send` as this value is used across an await
// --> $DIR/issue-70935-complex-spans.rs:13:9
// |
// LL | baz(|| async{
// | __________^___-
// | | _________|
// | ||
// LL | || foo(tx.clone());
// LL | || }).await;
// | || - ^- value is later dropped here
// | ||_________|______|
// | |__________| await occurs here, with value maybe used later
// | has type `closure` which is not `Send`
//
// So, detect it and separate into some notes, like:
//
// note: future is not `Send` as this value is used across an await
// --> $DIR/issue-70935-complex-spans.rs:13:9
// |
// LL | / baz(|| async{
// LL | | foo(tx.clone());
// LL | | }).await;
// | |________________^ first, await occurs here, with the value maybe used later...
// note: the value is later dropped here
// --> $DIR/issue-70935-complex-spans.rs:15:17
// |
// LL | }).await;
// | ^
//
// If available, use the scope span to annotate the drop location.
if let Some(scope_span) = scope_span {
let scope_span = source_map.end_point(scope_span);
let is_overlapped =
yield_span.overlaps(scope_span) || yield_span.overlaps(interior_span);
if is_overlapped {
span.push_span_label(
yield_span,
format!(
"first, {} occurs here, with {} maybe used later...",
await_or_yield, snippet
),
);
err.span_note(
span,
&format!(
"{} {} as this value is used across {}",
future_or_generator, trait_explanation, an_await_or_yield
),
);
err.span_note(scope_span, &format!("{} is later dropped here", snippet));
} else {
span.push_span_label(
yield_span,
Expand All @@ -1671,6 +1638,10 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
await_or_yield, snippet
),
);
span.push_span_label(
scope_span,
format!("{} is later dropped here", snippet),
);
span.push_span_label(
interior_span,
format!("has type `{}` which {}", target_ty, trait_explanation),
Expand All @@ -1683,8 +1654,28 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
),
);
}
} else {
span.push_span_label(
yield_span,
format!(
"{} occurs here, with {} maybe used later",
await_or_yield, snippet
),
);
span.push_span_label(
interior_span,
format!("has type `{}` which {}", target_ty, trait_explanation),
);
err.span_note(
span,
&format!(
"{} {} as this value is used across {}",
future_or_generator, trait_explanation, an_await_or_yield
),
);
}
};
}
};
match interior_or_upvar_span {
GeneratorInteriorOrUpvar::Interior(interior_span) => {
if let Some((scope_span, yield_span, expr, from_awaited_ty)) = interior_extra_info {
Expand Down
11 changes: 2 additions & 9 deletions src/test/ui/async-await/issue-70935-complex-spans.stderr
View file
Expand Up @@ -11,15 +11,8 @@ note: future is not `Send` as this value is used across an await
LL | / baz(|| async{
LL | | foo(tx.clone());
LL | | }).await;
| |________________^
note: first, await occurs here, with the value maybe used later
--> $DIR/issue-70935-complex-spans.rs:13:9
|
LL | / baz(|| async{
LL | | foo(tx.clone());
LL | | }).await;
| |________________^
note: ...but, the value is later dropped here
| |________________^ first, await occurs here, with the value maybe used later...
note: the value is later dropped here
--> $DIR/issue-70935-complex-spans.rs:15:17
|
LL | }).await;
Expand Down
9 changes: 2 additions & 7 deletions src/test/ui/async-await/issues/issue-65436-raw-ptr-not-send.stderr
View file
Expand Up @@ -12,13 +12,8 @@ note: future is not `Send` as this value is used across an await
--> $DIR/issue-65436-raw-ptr-not-send.rs:14:9
|
LL | bar(Foo(std::ptr::null())).await;
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
note: first, await occurs here, with `std::ptr::null()` maybe used later
--> $DIR/issue-65436-raw-ptr-not-send.rs:14:9
|
LL | bar(Foo(std::ptr::null())).await;
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
note: ...but, `std::ptr::null()` is later dropped here
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ first, await occurs here, with `std::ptr::null()` maybe used later...
note: `std::ptr::null()` is later dropped here
--> $DIR/issue-65436-raw-ptr-not-send.rs:14:41
|
LL | bar(Foo(std::ptr::null())).await;
Expand Down

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