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Rollup merge of #88501 - m-ou-se:prelude-collusion-oh-no-macros-help,…
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… r=estebank

Use right span in prelude collision suggestions with macros.

Fixes #88347

r? `@estebank`
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m-ou-se authored Aug 31, 2021
2 parents c5a34d8 + 7c0479b commit 91c4fee
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Showing 6 changed files with 148 additions and 19 deletions.
8 changes: 8 additions & 0 deletions compiler/rustc_span/src/lib.rs
Original file line number Diff line number Diff line change
Expand Up @@ -597,6 +597,14 @@ impl Span {
if !expn_data.is_root() { Some(expn_data.call_site) } else { None }
}

/// Walk down the expansion ancestors to find a span that's contained within `outer`.
pub fn find_ancestor_inside(mut self, outer: Span) -> Option<Span> {
while !outer.contains(self) {
self = self.parent()?;
}
Some(self)
}

/// Edition of the crate from which this span came.
pub fn edition(self) -> edition::Edition {
self.ctxt().edition()
Expand Down
36 changes: 22 additions & 14 deletions compiler/rustc_typeck/src/check/method/prelude2021.rs
Original file line number Diff line number Diff line change
Expand Up @@ -156,15 +156,16 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
segment.ident.name
));

let (self_adjusted, precise) = self.adjust_expr(pick, self_expr);
let (self_adjusted, precise) = self.adjust_expr(pick, self_expr, sp);
if precise {
let args = args
.iter()
.skip(1)
.map(|arg| {
let span = arg.span.find_ancestor_inside(sp).unwrap_or_default();
format!(
", {}",
self.sess().source_map().span_to_snippet(arg.span).unwrap()
self.sess().source_map().span_to_snippet(span).unwrap()
)
})
.collect::<String>();
Expand Down Expand Up @@ -272,11 +273,10 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
method_name.name
));

let mut self_ty_name = self
.sess()
.source_map()
.span_to_snippet(self_ty_span)
.unwrap_or_else(|_| self_ty.to_string());
let mut self_ty_name = self_ty_span
.find_ancestor_inside(span)
.and_then(|span| self.sess().source_map().span_to_snippet(span).ok())
.unwrap_or_else(|| self_ty.to_string());

// Get the number of generics the self type has (if an Adt) unless we can determine that
// the user has written the self type with generics already which we (naively) do by looking
Expand Down Expand Up @@ -370,7 +370,12 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
/// Creates a string version of the `expr` that includes explicit adjustments.
/// Returns the string and also a bool indicating whther this is a *precise*
/// suggestion.
fn adjust_expr(&self, pick: &Pick<'tcx>, expr: &hir::Expr<'tcx>) -> (String, bool) {
fn adjust_expr(
&self,
pick: &Pick<'tcx>,
expr: &hir::Expr<'tcx>,
outer: Span,
) -> (String, bool) {
let derefs = "*".repeat(pick.autoderefs);

let autoref = match pick.autoref_or_ptr_adjustment {
Expand All @@ -379,12 +384,15 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
Some(probe::AutorefOrPtrAdjustment::ToConstPtr) | None => "",
};

let (expr_text, precise) =
if let Ok(expr_text) = self.sess().source_map().span_to_snippet(expr.span) {
(expr_text, true)
} else {
("(..)".to_string(), false)
};
let (expr_text, precise) = if let Some(expr_text) = expr
.span
.find_ancestor_inside(outer)
.and_then(|span| self.sess().source_map().span_to_snippet(span).ok())
{
(expr_text, true)
} else {
("(..)".to_string(), false)
};

let adjusted_text = if let Some(probe::AutorefOrPtrAdjustment::ToConstPtr) =
pick.autoref_or_ptr_adjustment
Expand Down
8 changes: 3 additions & 5 deletions compiler/rustc_typeck/src/check/upvar.rs
Original file line number Diff line number Diff line change
Expand Up @@ -680,15 +680,13 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
migrated_variables_concat
);

let mut closure_body_span = self.tcx.hir().span(body_id.hir_id);

// If the body was entirely expanded from a macro
// invocation, i.e. the body is not contained inside the
// closure span, then we walk up the expansion until we
// find the span before the expansion.
while !closure_body_span.is_dummy() && !closure_span.contains(closure_body_span) {
closure_body_span = closure_body_span.parent().unwrap_or(DUMMY_SP);
}
let closure_body_span = self.tcx.hir().span(body_id.hir_id)
.find_ancestor_inside(closure_span)
.unwrap_or(DUMMY_SP);

if let Ok(s) = self.tcx.sess.source_map().span_to_snippet(closure_body_span) {
let mut lines = s.lines();
Expand Down
45 changes: 45 additions & 0 deletions src/test/ui/rust-2021/future-prelude-collision-macros.fixed
Original file line number Diff line number Diff line change
@@ -0,0 +1,45 @@
// run-rustfix
// edition:2018
// check-pass
#![warn(rust_2021_prelude_collisions)]
#![allow(unreachable_code)]

macro_rules! foo {
() => {{
123;
S
}};
}

trait MyTry<T> {
fn try_into(self, _: u8);
}

struct S;

impl MyTry<i32> for S {
fn try_into(self, _: u8) {}
}

trait TryFromU8: Sized {
fn try_from(_: u8);
}

impl TryFromU8 for u32 {
fn try_from(_: u8) {}
}

macro_rules! bar {
() => {
u32
};
}

fn main() {
MyTry::try_into(foo!(), todo!());
//~^ WARNING trait method `try_into` will become ambiguous in Rust 2021
//~| WARNING this is accepted in the current edition
<bar!() as TryFromU8>::try_from(0);
//~^ WARNING trait-associated function `try_from` will become ambiguous in Rust 2021
//~| WARNING this is accepted in the current edition
}
45 changes: 45 additions & 0 deletions src/test/ui/rust-2021/future-prelude-collision-macros.rs
Original file line number Diff line number Diff line change
@@ -0,0 +1,45 @@
// run-rustfix
// edition:2018
// check-pass
#![warn(rust_2021_prelude_collisions)]
#![allow(unreachable_code)]

macro_rules! foo {
() => {{
123;
S
}};
}

trait MyTry<T> {
fn try_into(self, _: u8);
}

struct S;

impl MyTry<i32> for S {
fn try_into(self, _: u8) {}
}

trait TryFromU8: Sized {
fn try_from(_: u8);
}

impl TryFromU8 for u32 {
fn try_from(_: u8) {}
}

macro_rules! bar {
() => {
u32
};
}

fn main() {
foo!().try_into(todo!());
//~^ WARNING trait method `try_into` will become ambiguous in Rust 2021
//~| WARNING this is accepted in the current edition
<bar!()>::try_from(0);
//~^ WARNING trait-associated function `try_from` will become ambiguous in Rust 2021
//~| WARNING this is accepted in the current edition
}
25 changes: 25 additions & 0 deletions src/test/ui/rust-2021/future-prelude-collision-macros.stderr
Original file line number Diff line number Diff line change
@@ -0,0 +1,25 @@
warning: trait method `try_into` will become ambiguous in Rust 2021
--> $DIR/future-prelude-collision-macros.rs:39:5
|
LL | foo!().try_into(todo!());
| ^^^^^^^^^^^^^^^^^^^^^^^^ help: disambiguate the associated function: `MyTry::try_into(foo!(), todo!())`
|
note: the lint level is defined here
--> $DIR/future-prelude-collision-macros.rs:4:9
|
LL | #![warn(rust_2021_prelude_collisions)]
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
= warning: this is accepted in the current edition (Rust 2018) but is a hard error in Rust 2021!
= note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/prelude.html>

warning: trait-associated function `try_from` will become ambiguous in Rust 2021
--> $DIR/future-prelude-collision-macros.rs:42:5
|
LL | <bar!()>::try_from(0);
| ^^^^^^^^^^^^^^^^^^ help: disambiguate the associated function: `<bar!() as TryFromU8>::try_from`
|
= warning: this is accepted in the current edition (Rust 2018) but is a hard error in Rust 2021!
= note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/prelude.html>

warning: 2 warnings emitted

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