diff options
5 files changed, 358 insertions, 1 deletions
diff --git a/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs b/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs index 9aebe77a104..fd52d629660 100644 --- a/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs +++ b/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs @@ -3611,13 +3611,103 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { let mut prev_ty = self.resolve_vars_if_possible( typeck_results.expr_ty_adjusted_opt(expr).unwrap_or(Ty::new_misc_error(tcx)), ); - while let hir::ExprKind::MethodCall(_path_segment, rcvr_expr, _args, span) = expr.kind { + while let hir::ExprKind::MethodCall(path_segment, rcvr_expr, args, span) = expr.kind { // Point at every method call in the chain with the resulting type. // vec![1, 2, 3].iter().map(mapper).sum<i32>() // ^^^^^^ ^^^^^^^^^^^ expr = rcvr_expr; let assocs_in_this_method = self.probe_assoc_types_at_expr(&type_diffs, span, prev_ty, expr.hir_id, param_env); + // Special case for iterator chains, we look at potential failures of `Iterator::Item` + // not being `: Clone` and `Iterator::map` calls with spurious trailing `;`. + for entry in &assocs_in_this_method { + let Some((_span, (def_id, ty))) = entry else { + continue; + }; + for diff in &type_diffs { + let Sorts(expected_found) = diff else { + continue; + }; + if tcx.is_diagnostic_item(sym::IteratorItem, *def_id) + && path_segment.ident.name == sym::map + && self.can_eq(param_env, expected_found.found, *ty) + && let [arg] = args + && let hir::ExprKind::Closure(closure) = arg.kind + { + let body = tcx.hir().body(closure.body); + if let hir::ExprKind::Block(block, None) = body.value.kind + && let None = block.expr + && let [.., stmt] = block.stmts + && let hir::StmtKind::Semi(expr) = stmt.kind + // FIXME: actually check the expected vs found types, but right now + // the expected is a projection that we need to resolve. + // && let Some(tail_ty) = typeck_results.expr_ty_opt(expr) + && expected_found.found.is_unit() + { + err.span_suggestion_verbose( + expr.span.shrink_to_hi().with_hi(stmt.span.hi()), + "consider removing this semicolon", + String::new(), + Applicability::MachineApplicable, + ); + } + let expr = if let hir::ExprKind::Block(block, None) = body.value.kind + && let Some(expr) = block.expr + { + expr + } else { + body.value + }; + if let hir::ExprKind::MethodCall(path_segment, rcvr, [], span) = expr.kind + && path_segment.ident.name == sym::clone + && let Some(expr_ty) = typeck_results.expr_ty_opt(expr) + && let Some(rcvr_ty) = typeck_results.expr_ty_opt(rcvr) + && self.can_eq(param_env, expr_ty, rcvr_ty) + && let ty::Ref(_, ty, _) = expr_ty.kind() + { + err.span_label( + span, + format!( + "this method call is cloning the reference `{expr_ty}`, not \ + `{ty}` which doesn't implement `Clone`", + ), + ); + let ty::Param(..) = ty.kind() else { + continue; + }; + let hir = tcx.hir(); + let node = hir.get_by_def_id(hir.get_parent_item(expr.hir_id).def_id); + + let pred = ty::Binder::dummy(ty::TraitPredicate { + trait_ref: ty::TraitRef::from_lang_item( + tcx, + LangItem::Clone, + span, + [*ty], + ), + polarity: ty::ImplPolarity::Positive, + }); + let Some(generics) = node.generics() else { + continue; + }; + let Some(body_id) = node.body_id() else { + continue; + }; + suggest_restriction( + tcx, + hir.body_owner_def_id(body_id), + &generics, + &format!("type parameter `{ty}`"), + err, + node.fn_sig(), + None, + pred, + None, + ); + } + } + } + } assocs.push(assocs_in_this_method); prev_ty = self.resolve_vars_if_possible( typeck_results.expr_ty_adjusted_opt(expr).unwrap_or(Ty::new_misc_error(tcx)), diff --git a/tests/ui/iterators/invalid-iterator-chain-fixable.fixed b/tests/ui/iterators/invalid-iterator-chain-fixable.fixed new file mode 100644 index 00000000000..513b5bd13d8 --- /dev/null +++ b/tests/ui/iterators/invalid-iterator-chain-fixable.fixed @@ -0,0 +1,42 @@ +// run-rustfix +use std::collections::hash_set::Iter; +use std::collections::HashSet; + +fn iter_to_vec<'b, X>(i: Iter<'b, X>) -> Vec<X> where X: Clone { + let i = i.map(|x| x.clone()); + i.collect() //~ ERROR E0277 +} + +fn main() { + let v = vec![(0, 0)]; + let scores = v + .iter() + .map(|(a, b)| { + a + b + }); + println!("{}", scores.sum::<i32>()); //~ ERROR E0277 + println!( + "{}", + vec![0, 1] + .iter() + .map(|x| x * 2) + .map(|x| { x }) + .map(|x| { x }) + .sum::<i32>(), //~ ERROR E0277 + ); + println!("{}", vec![0, 1].iter().map(|x| { x }).sum::<i32>()); //~ ERROR E0277 + let a = vec![0]; + let b = a.into_iter(); + let c = b.map(|x| x + 1); + let d = c.filter(|x| *x > 10 ); + let e = d.map(|x| { + x + 1 + }); + let f = e.filter(|_| false); + let g: Vec<i32> = f.collect(); //~ ERROR E0277 + println!("{g:?}"); + + let mut s = HashSet::new(); + s.insert(1u8); + println!("{:?}", iter_to_vec(s.iter())); +} diff --git a/tests/ui/iterators/invalid-iterator-chain-fixable.rs b/tests/ui/iterators/invalid-iterator-chain-fixable.rs new file mode 100644 index 00000000000..79b861702c7 --- /dev/null +++ b/tests/ui/iterators/invalid-iterator-chain-fixable.rs @@ -0,0 +1,42 @@ +// run-rustfix +use std::collections::hash_set::Iter; +use std::collections::HashSet; + +fn iter_to_vec<'b, X>(i: Iter<'b, X>) -> Vec<X> { + let i = i.map(|x| x.clone()); + i.collect() //~ ERROR E0277 +} + +fn main() { + let v = vec![(0, 0)]; + let scores = v + .iter() + .map(|(a, b)| { + a + b; + }); + println!("{}", scores.sum::<i32>()); //~ ERROR E0277 + println!( + "{}", + vec![0, 1] + .iter() + .map(|x| x * 2) + .map(|x| { x; }) + .map(|x| { x }) + .sum::<i32>(), //~ ERROR E0277 + ); + println!("{}", vec![0, 1].iter().map(|x| { x; }).sum::<i32>()); //~ ERROR E0277 + let a = vec![0]; + let b = a.into_iter(); + let c = b.map(|x| x + 1); + let d = c.filter(|x| *x > 10 ); + let e = d.map(|x| { + x + 1; + }); + let f = e.filter(|_| false); + let g: Vec<i32> = f.collect(); //~ ERROR E0277 + println!("{g:?}"); + + let mut s = HashSet::new(); + s.insert(1u8); + println!("{:?}", iter_to_vec(s.iter())); +} diff --git a/tests/ui/iterators/invalid-iterator-chain-fixable.stderr b/tests/ui/iterators/invalid-iterator-chain-fixable.stderr new file mode 100644 index 00000000000..1bfe765e78a --- /dev/null +++ b/tests/ui/iterators/invalid-iterator-chain-fixable.stderr @@ -0,0 +1,157 @@ +error[E0277]: a value of type `Vec<X>` cannot be built from an iterator over elements of type `&X` + --> $DIR/invalid-iterator-chain-fixable.rs:7:7 + | +LL | let i = i.map(|x| x.clone()); + | ------- this method call is cloning the reference `&X`, not `X` which doesn't implement `Clone` +LL | i.collect() + | ^^^^^^^ value of type `Vec<X>` cannot be built from `std::iter::Iterator<Item=&X>` + | + = help: the trait `FromIterator<&X>` is not implemented for `Vec<X>` + = help: the trait `FromIterator<X>` is implemented for `Vec<X>` + = help: for that trait implementation, expected `X`, found `&X` +note: the method call chain might not have had the expected associated types + --> $DIR/invalid-iterator-chain-fixable.rs:5:26 + | +LL | fn iter_to_vec<'b, X>(i: Iter<'b, X>) -> Vec<X> { + | ^^^^^^^^^^^ `Iterator::Item` is `&X` here +LL | let i = i.map(|x| x.clone()); + | ------------------ `Iterator::Item` remains `&X` here +note: required by a bound in `collect` + --> $SRC_DIR/core/src/iter/traits/iterator.rs:LL:COL +help: consider further restricting type parameter `X` + | +LL | fn iter_to_vec<'b, X>(i: Iter<'b, X>) -> Vec<X> where X: Clone { + | ++++++++++++++ + +error[E0277]: a value of type `i32` cannot be made by summing an iterator over elements of type `()` + --> $DIR/invalid-iterator-chain-fixable.rs:17:33 + | +LL | println!("{}", scores.sum::<i32>()); + | --- ^^^ value of type `i32` cannot be made by summing a `std::iter::Iterator<Item=()>` + | | + | required by a bound introduced by this call + | + = help: the trait `Sum<()>` is not implemented for `i32` + = help: the following other types implement trait `Sum<A>`: + <i32 as Sum> + <i32 as Sum<&'a i32>> +note: the method call chain might not have had the expected associated types + --> $DIR/invalid-iterator-chain-fixable.rs:14:10 + | +LL | let v = vec![(0, 0)]; + | ------------ this expression has type `Vec<({integer}, {integer})>` +LL | let scores = v +LL | .iter() + | ------ `Iterator::Item` is `&({integer}, {integer})` here +LL | .map(|(a, b)| { + | __________^ +LL | | a + b; +LL | | }); + | |__________^ `Iterator::Item` changed to `()` here +note: required by a bound in `std::iter::Iterator::sum` + --> $SRC_DIR/core/src/iter/traits/iterator.rs:LL:COL +help: consider removing this semicolon + | +LL - a + b; +LL + a + b + | + +error[E0277]: a value of type `i32` cannot be made by summing an iterator over elements of type `()` + --> $DIR/invalid-iterator-chain-fixable.rs:25:20 + | +LL | .sum::<i32>(), + | --- ^^^ value of type `i32` cannot be made by summing a `std::iter::Iterator<Item=()>` + | | + | required by a bound introduced by this call + | + = help: the trait `Sum<()>` is not implemented for `i32` + = help: the following other types implement trait `Sum<A>`: + <i32 as Sum> + <i32 as Sum<&'a i32>> +note: the method call chain might not have had the expected associated types + --> $DIR/invalid-iterator-chain-fixable.rs:23:14 + | +LL | vec![0, 1] + | ---------- this expression has type `Vec<{integer}>` +LL | .iter() + | ------ `Iterator::Item` is `&{integer}` here +LL | .map(|x| x * 2) + | -------------- `Iterator::Item` changed to `{integer}` here +LL | .map(|x| { x; }) + | ^^^^^^^^^^^^^^^ `Iterator::Item` changed to `()` here +LL | .map(|x| { x }) + | -------------- `Iterator::Item` remains `()` here +note: required by a bound in `std::iter::Iterator::sum` + --> $SRC_DIR/core/src/iter/traits/iterator.rs:LL:COL +help: consider removing this semicolon + | +LL - .map(|x| { x; }) +LL + .map(|x| { x }) + | + +error[E0277]: a value of type `i32` cannot be made by summing an iterator over elements of type `()` + --> $DIR/invalid-iterator-chain-fixable.rs:27:60 + | +LL | println!("{}", vec![0, 1].iter().map(|x| { x; }).sum::<i32>()); + | --- ^^^ value of type `i32` cannot be made by summing a `std::iter::Iterator<Item=()>` + | | + | required by a bound introduced by this call + | + = help: the trait `Sum<()>` is not implemented for `i32` + = help: the following other types implement trait `Sum<A>`: + <i32 as Sum> + <i32 as Sum<&'a i32>> +note: the method call chain might not have had the expected associated types + --> $DIR/invalid-iterator-chain-fixable.rs:27:38 + | +LL | println!("{}", vec![0, 1].iter().map(|x| { x; }).sum::<i32>()); + | ---------- ------ ^^^^^^^^^^^^^^^ `Iterator::Item` changed to `()` here + | | | + | | `Iterator::Item` is `&{integer}` here + | this expression has type `Vec<{integer}>` +note: required by a bound in `std::iter::Iterator::sum` + --> $SRC_DIR/core/src/iter/traits/iterator.rs:LL:COL +help: consider removing this semicolon + | +LL - println!("{}", vec![0, 1].iter().map(|x| { x; }).sum::<i32>()); +LL + println!("{}", vec![0, 1].iter().map(|x| { x }).sum::<i32>()); + | + +error[E0277]: a value of type `Vec<i32>` cannot be built from an iterator over elements of type `()` + --> $DIR/invalid-iterator-chain-fixable.rs:36:25 + | +LL | let g: Vec<i32> = f.collect(); + | ^^^^^^^ value of type `Vec<i32>` cannot be built from `std::iter::Iterator<Item=()>` + | + = help: the trait `FromIterator<()>` is not implemented for `Vec<i32>` + = help: the trait `FromIterator<i32>` is implemented for `Vec<i32>` + = help: for that trait implementation, expected `i32`, found `()` +note: the method call chain might not have had the expected associated types + --> $DIR/invalid-iterator-chain-fixable.rs:32:15 + | +LL | let a = vec![0]; + | ------- this expression has type `Vec<{integer}>` +LL | let b = a.into_iter(); + | ----------- `Iterator::Item` is `{integer}` here +LL | let c = b.map(|x| x + 1); + | -------------- `Iterator::Item` remains `{integer}` here +LL | let d = c.filter(|x| *x > 10 ); + | -------------------- `Iterator::Item` remains `{integer}` here +LL | let e = d.map(|x| { + | _______________^ +LL | | x + 1; +LL | | }); + | |______^ `Iterator::Item` changed to `()` here +LL | let f = e.filter(|_| false); + | ----------------- `Iterator::Item` remains `()` here +note: required by a bound in `collect` + --> $SRC_DIR/core/src/iter/traits/iterator.rs:LL:COL +help: consider removing this semicolon + | +LL - x + 1; +LL + x + 1 + | + +error: aborting due to 5 previous errors + +For more information about this error, try `rustc --explain E0277`. diff --git a/tests/ui/iterators/invalid-iterator-chain.stderr b/tests/ui/iterators/invalid-iterator-chain.stderr index 2601c9c0d69..4dc13086912 100644 --- a/tests/ui/iterators/invalid-iterator-chain.stderr +++ b/tests/ui/iterators/invalid-iterator-chain.stderr @@ -1,6 +1,8 @@ error[E0277]: a value of type `Vec<X>` cannot be built from an iterator over elements of type `&X` --> $DIR/invalid-iterator-chain.rs:6:7 | +LL | let i = i.map(|x| x.clone()); + | ------- this method call is cloning the reference `&X`, not `X` which doesn't implement `Clone` LL | i.collect() | ^^^^^^^ value of type `Vec<X>` cannot be built from `std::iter::Iterator<Item=&X>` | @@ -16,6 +18,10 @@ LL | let i = i.map(|x| x.clone()); | ------------------ `Iterator::Item` remains `&X` here note: required by a bound in `collect` --> $SRC_DIR/core/src/iter/traits/iterator.rs:LL:COL +help: consider further restricting type parameter `X` + | +LL | fn iter_to_vec<'b, X>(i: Iter<'b, X>) -> Vec<X> where X: Clone { + | ++++++++++++++ error[E0277]: a value of type `i32` cannot be made by summing an iterator over elements of type `()` --> $DIR/invalid-iterator-chain.rs:15:33 @@ -43,6 +49,11 @@ LL | | }); | |__________^ `Iterator::Item` changed to `()` here note: required by a bound in `std::iter::Iterator::sum` --> $SRC_DIR/core/src/iter/traits/iterator.rs:LL:COL +help: consider removing this semicolon + | +LL - a + b; +LL + a + b + | error[E0277]: a value of type `i32` cannot be made by summing an iterator over elements of type `()` --> $DIR/invalid-iterator-chain.rs:26:20 @@ -77,6 +88,11 @@ LL | .map(|x| { x; }) | ^^^^^^^^^^^^^^^ `Iterator::Item` changed to `()` here note: required by a bound in `std::iter::Iterator::sum` --> $SRC_DIR/core/src/iter/traits/iterator.rs:LL:COL +help: consider removing this semicolon + | +LL - .map(|x| { x; }) +LL + .map(|x| { x }) + | error[E0277]: a value of type `i32` cannot be made by summing an iterator over elements of type `f64` --> $DIR/invalid-iterator-chain.rs:36:20 @@ -130,6 +146,11 @@ LL | println!("{}", vec![0, 1].iter().map(|x| { x; }).sum::<i32>()); | this expression has type `Vec<{integer}>` note: required by a bound in `std::iter::Iterator::sum` --> $SRC_DIR/core/src/iter/traits/iterator.rs:LL:COL +help: consider removing this semicolon + | +LL - println!("{}", vec![0, 1].iter().map(|x| { x; }).sum::<i32>()); +LL + println!("{}", vec![0, 1].iter().map(|x| { x }).sum::<i32>()); + | error[E0277]: a value of type `i32` cannot be made by summing an iterator over elements of type `&()` --> $DIR/invalid-iterator-chain.rs:39:46 @@ -182,6 +203,11 @@ LL | let f = e.filter(|_| false); | ----------------- `Iterator::Item` remains `()` here note: required by a bound in `collect` --> $SRC_DIR/core/src/iter/traits/iterator.rs:LL:COL +help: consider removing this semicolon + | +LL - x + 1; +LL + x + 1 + | error: aborting due to 7 previous errors |