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Diagnose incorrect usages of the question mark operator

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This commit is contained in:
Lukas Wirth 2022-10-05 19:15:07 +02:00
parent 8406380b5a
commit 381366f1dd
13 changed files with 289 additions and 125 deletions
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1
crates/hir-expand/src/mod_path.rs
View file

@ -259,6 +259,7 @@ macro_rules! __known_path {
(core::future::Future) => {};
(core::future::IntoFuture) => {};
(core::ops::Try) => {};
(core::ops::FromResidual) => {};
($path:path) => {
compile_error!("Please register your known path in the path module")
};

2
crates/hir-expand/src/name.rs
View file

@ -279,6 +279,8 @@ pub mod known {
RangeToInclusive,
RangeTo,
Range,
Residual,
FromResidual,
Neg,
Not,
None,

13
crates/hir-ty/src/infer.rs
View file

@ -190,7 +190,9 @@ pub(crate) type InferResult<T> = Result<InferOk<T>, TypeError>;
pub enum InferenceDiagnostic {
NoSuchField { expr: ExprId },
BreakOutsideOfLoop { expr: ExprId, is_break: bool },
IncorrectTryTarget { expr: ExprId },
MismatchedArgCount { call_expr: ExprId, expected: usize, found: usize },
DoesNotImplement { expr: ExprId, trait_: TraitId, ty: Ty },
}
/// A mismatch between an expected and an inferred type.
@ -905,17 +907,6 @@ impl<'a> InferenceContext<'a> {
self.db.trait_data(trait_).associated_type_by_name(&name![Item])
}
fn resolve_ops_try_ok(&self) -> Option<TypeAliasId> {
// FIXME resolve via lang_item once try v2 is stable
let path = path![core::ops::Try];
let trait_ = self.resolver.resolve_known_trait(self.db.upcast(), &path)?;
let trait_data = self.db.trait_data(trait_);
trait_data
// FIXME remove once try v2 is stable
.associated_type_by_name(&name![Ok])
.or_else(|| trait_data.associated_type_by_name(&name![Output]))
}
fn resolve_ops_neg_output(&self) -> Option<TypeAliasId> {
let trait_ = self.resolve_lang_item(name![neg])?.as_trait()?;
self.db.trait_data(trait_).associated_type_by_name(&name![Output])

99
crates/hir-ty/src/infer/expr.rs
View file

@ -19,24 +19,24 @@ use hir_def::{
resolver::resolver_for_expr,
ConstParamId, FieldId, ItemContainerId, Lookup,
};
use hir_expand::name::Name;
use hir_expand::{name, name::Name};
use stdx::always;
use syntax::ast::RangeOp;
use crate::{
autoderef::{self, Autoderef},
consteval,
infer::{coerce::CoerceMany, find_continuable, BreakableKind},
infer::{coerce::CoerceMany, find_continuable, path, BreakableKind},
lower::{
const_or_path_to_chalk, generic_arg_to_chalk, lower_to_chalk_mutability, ParamLoweringMode,
},
mapping::{from_chalk, ToChalk},
method_resolution::{self, lang_names_for_bin_op, VisibleFromModule},
primitive::{self, UintTy},
static_lifetime, to_chalk_trait_id,
static_lifetime, to_assoc_type_id, to_chalk_trait_id,
utils::{generics, Generics},
AdtId, Binders, CallableDefId, FnPointer, FnSig, FnSubst, Interner, Rawness, Scalar,
Substitution, TraitRef, Ty, TyBuilder, TyExt, TyKind,
AdtId, AliasEq, AliasTy, Binders, CallableDefId, FnPointer, FnSig, FnSubst, Interner,
ProjectionTy, Rawness, Scalar, Substitution, TraitRef, Ty, TyBuilder, TyExt, TyKind,
};
use super::{
@ -564,9 +564,29 @@ impl<'a> InferenceContext<'a> {
let inner_ty = self.infer_expr_inner(*expr, &Expectation::none());
self.resolve_associated_type(inner_ty, self.resolve_future_future_output())
}
Expr::Try { expr } => {
let inner_ty = self.infer_expr_inner(*expr, &Expectation::none());
self.resolve_associated_type(inner_ty, self.resolve_ops_try_ok())
&Expr::Try { expr } => {
let inner_ty = self.infer_expr_inner(expr, &Expectation::none());
match self.resolve_try_impl_for(inner_ty.clone()) {
Some((_, Some((output, residual)))) => {
if let Some((_trait, false)) =
self.implements_from_residual(self.return_ty.clone(), residual)
{
self.push_diagnostic(InferenceDiagnostic::IncorrectTryTarget {
expr: tgt_expr,
});
}
output
}
Some((trait_, None)) => {
self.push_diagnostic(InferenceDiagnostic::DoesNotImplement {
expr,
trait_,
ty: inner_ty,
});
self.err_ty()
}
None => self.err_ty(),
}
}
Expr::Cast { expr, type_ref } => {
// FIXME: propagate the "castable to" expectation (and find a test case that shows this is necessary)
@ -1530,4 +1550,67 @@ impl<'a> InferenceContext<'a> {
let ctx = self.breakables.pop().expect("breakable stack broken");
(ctx.may_break.then(|| ctx.coerce.complete()), res)
}
/// Check whether `ty` implements `FromResidual<r>`
fn implements_from_residual(&mut self, ty: Ty, r: Ty) -> Option<(hir_def::TraitId, bool)> {
let from_residual_trait = self
.resolver
.resolve_known_trait(self.db.upcast(), &(super::path![core::ops::FromResidual]))?;
let r = GenericArgData::Ty(r).intern(Interner);
let b = TyBuilder::trait_ref(self.db, from_residual_trait);
if b.remaining() != 2 {
return Some((from_residual_trait, false));
}
let trait_ref = b.push(ty).push(r).build();
Some((from_residual_trait, self.table.try_obligation(trait_ref.cast(Interner)).is_some()))
}
fn resolve_try_impl_for(&mut self, ty: Ty) -> Option<(hir_def::TraitId, Option<(Ty, Ty)>)> {
let path = path![core::ops::Try];
let trait_ = self.resolver.resolve_known_trait(self.db.upcast(), &path)?;
let trait_ref = TyBuilder::trait_ref(self.db, trait_).push(ty).build();
let substitution = trait_ref.substitution.clone();
self.push_obligation(trait_ref.clone().cast(Interner));
let trait_data = self.db.trait_data(trait_);
let output = trait_data.associated_type_by_name(&name![Output]);
let residual = trait_data.associated_type_by_name(&name![Residual]);
let output_ty = match output {
Some(output) => {
let output_ty = self.table.new_type_var();
let alias_eq = AliasEq {
alias: AliasTy::Projection(ProjectionTy {
associated_ty_id: to_assoc_type_id(output),
substitution: substitution.clone(),
}),
ty: output_ty.clone(),
};
self.push_obligation(alias_eq.cast(Interner));
output_ty
}
None => self.err_ty(),
};
let residual_ty = match residual {
Some(residual) => {
let residual_ty = self.table.new_type_var();
let alias_eq = AliasEq {
alias: AliasTy::Projection(ProjectionTy {
associated_ty_id: to_assoc_type_id(residual),
substitution,
}),
ty: residual_ty.clone(),
};
self.push_obligation(alias_eq.cast(Interner));
residual_ty
}
None => self.err_ty(),
};
// FIXME: We are doing the work twice here I think?
Some((
trait_,
self.table.try_obligation(trait_ref.cast(Interner)).map(|_| (output_ty, residual_ty)),
))
}
}

18
crates/hir-ty/src/method_resolution.rs
View file

@ -1111,6 +1111,24 @@ pub fn resolve_indexing_op(
}
None
}
/// Returns the receiver type for the try branch trait call.
pub fn resolve_branch_op(
db: &dyn HirDatabase,
env: Arc<TraitEnvironment>,
ty: Canonical<Ty>,
try_trait: TraitId,
) -> Option<ReceiverAdjustments> {
let mut table = InferenceTable::new(db, env.clone());
let ty = table.instantiate_canonical(ty);
let (deref_chain, adj) = autoderef_method_receiver(&mut table, ty);
for (ty, adj) in deref_chain.into_iter().zip(adj) {
let goal = generic_implements_goal(db, env.clone(), try_trait, &ty);
if db.trait_solve(env.krate, goal.cast(Interner)).is_some() {
return Some(adj);
}
}
None
}
macro_rules! check_that {
($cond:expr) => {

92
crates/hir-ty/src/tests/traits.rs
View file

@ -162,98 +162,16 @@ fn test() {
);
}
#[test]
fn infer_try() {
check_types(
r#"
//- /main.rs crate:main deps:core
fn test() {
let r: Result<i32, u64> = Result::Ok(1);
let v = r?;
v;
} //^ i32
//- /core.rs crate:core
pub mod ops {
pub trait Try {
type Ok;
type Error;
}
}
pub mod result {
pub enum Result<O, E> {
Ok(O),
Err(E)
}
impl<O, E> crate::ops::Try for Result<O, E> {
type Ok = O;
type Error = E;
}
}
pub mod prelude {
pub mod rust_2018 {
pub use crate::{result::*, ops::*};
}
}
"#,
);
}
#[test]
fn infer_try_trait_v2() {
check_types(
r#"
//- /main.rs crate:main deps:core
fn test() {
let r: Result<i32, u64> = Result::Ok(1);
//- minicore: try
fn test() -> core::ops::ControlFlow<u32, f32> {
let r: core::ops::ControlFlow<u32, f32> = core::ops::ControlFlow::Continue(1.0);
let v = r?;
v;
} //^ i32
//- /core.rs crate:core
mod ops {
mod try_trait {
pub trait Try: FromResidual {
type Output;
type Residual;
}
pub trait FromResidual<R = <Self as Try>::Residual> {}
}
pub use self::try_trait::FromResidual;
pub use self::try_trait::Try;
}
mod convert {
pub trait From<T> {}
impl<T> From<T> for T {}
}
pub mod result {
use crate::convert::From;
use crate::ops::{Try, FromResidual};
pub enum Infallible {}
pub enum Result<O, E> {
Ok(O),
Err(E)
}
impl<O, E> Try for Result<O, E> {
type Output = O;
type Error = Result<Infallible, E>;
}
impl<T, E, F: From<E>> FromResidual<Result<Infallible, E>> for Result<T, F> {}
}
pub mod prelude {
pub mod rust_2018 {
pub use crate::result::*;
}
//^ f32
r
}
"#,
);

14
crates/hir/src/diagnostics.rs
View file

@ -6,7 +6,7 @@
use base_db::CrateId;
use cfg::{CfgExpr, CfgOptions};
use either::Either;
use hir_def::path::ModPath;
use hir_def::{path::ModPath, TraitId};
use hir_expand::{name::Name, HirFileId, InFile};
use syntax::{ast, AstPtr, SyntaxNodePtr, TextRange};
@ -33,6 +33,7 @@ diagnostics![
BreakOutsideOfLoop,
InactiveCode,
IncorrectCase,
IncorrectTryExpr,
InvalidDeriveTarget,
MacroError,
MalformedDerive,
@ -40,6 +41,7 @@ diagnostics![
MissingFields,
MissingMatchArms,
MissingUnsafe,
NotImplemented,
NoSuchField,
ReplaceFilterMapNextWithFindMap,
TypeMismatch,
@ -153,6 +155,16 @@ pub struct MismatchedArgCount {
pub expected: usize,
pub found: usize,
}
#[derive(Debug)]
pub struct IncorrectTryExpr {
pub expr: InFile<AstPtr<ast::Expr>>,
}
#[derive(Debug)]
pub struct NotImplemented {
pub expr: InFile<AstPtr<ast::Expr>>,
pub trait_: TraitId,
pub ty: Type,
}
#[derive(Debug)]
pub struct MissingMatchArms {

38
crates/hir/src/lib.rs
View file

@ -81,11 +81,12 @@ use crate::db::{DefDatabase, HirDatabase};
pub use crate::{
attrs::{HasAttrs, Namespace},
diagnostics::{
AnyDiagnostic, BreakOutsideOfLoop, InactiveCode, IncorrectCase, InvalidDeriveTarget,
MacroError, MalformedDerive, MismatchedArgCount, MissingFields, MissingMatchArms,
MissingUnsafe, NoSuchField, ReplaceFilterMapNextWithFindMap, TypeMismatch,
UnimplementedBuiltinMacro, UnresolvedExternCrate, UnresolvedImport, UnresolvedMacroCall,
UnresolvedModule, UnresolvedProcMacro,
AnyDiagnostic, BreakOutsideOfLoop, InactiveCode, IncorrectCase, IncorrectTryExpr,
InvalidDeriveTarget, MacroError, MalformedDerive, MismatchedArgCount, MissingFields,
MissingMatchArms, MissingUnsafe, NoSuchField, NotImplemented,
ReplaceFilterMapNextWithFindMap, TypeMismatch, UnimplementedBuiltinMacro,
UnresolvedExternCrate, UnresolvedImport, UnresolvedMacroCall, UnresolvedModule,
UnresolvedProcMacro,
},
has_source::HasSource,
semantics::{PathResolution, Semantics, SemanticsScope, TypeInfo, VisibleTraits},
@ -1282,30 +1283,45 @@ impl DefWithBody {
let infer = db.infer(self.into());
let source_map = Lazy::new(|| db.body_with_source_map(self.into()).1);
for d in &infer.diagnostics {
match d {
match *d {
hir_ty::InferenceDiagnostic::NoSuchField { expr } => {
let field = source_map.field_syntax(*expr);
let field = source_map.field_syntax(expr);
acc.push(NoSuchField { field }.into())
}
&hir_ty::InferenceDiagnostic::BreakOutsideOfLoop { expr, is_break } => {
hir_ty::InferenceDiagnostic::BreakOutsideOfLoop { expr, is_break } => {
let expr = source_map
.expr_syntax(expr)
.expect("break outside of loop in synthetic syntax");
acc.push(BreakOutsideOfLoop { expr, is_break }.into())
}
hir_ty::InferenceDiagnostic::MismatchedArgCount { call_expr, expected, found } => {
match source_map.expr_syntax(*call_expr) {
match source_map.expr_syntax(call_expr) {
Ok(source_ptr) => acc.push(
MismatchedArgCount {
call_expr: source_ptr,
expected: *expected,
found: *found,
expected: expected,
found: found,
}
.into(),
),
Err(SyntheticSyntax) => (),
}
}
hir_ty::InferenceDiagnostic::IncorrectTryTarget { expr } => {
let expr = source_map.expr_syntax(expr).expect("try in synthetic syntax");
acc.push(IncorrectTryExpr { expr }.into())
}
hir_ty::InferenceDiagnostic::DoesNotImplement { expr, trait_, ref ty } => {
let expr = source_map.expr_syntax(expr).expect("try in synthetic syntax");
acc.push(
NotImplemented {
expr,
trait_,
ty: Type::new(db, DefWithBodyId::from(self), ty.clone()),
}
.into(),
)
}
}
}
for (expr, mismatch) in infer.expr_type_mismatches() {

37
crates/ide-diagnostics/src/handlers/incorrect_try_expr.rs Normal file
View file

@ -0,0 +1,37 @@
use hir::InFile;
use crate::{Diagnostic, DiagnosticsContext};
// Diagnostic: incorrect-try-target
//
// This diagnostic is triggered if a question mark operator was used in a context where it is not applicable.
pub(crate) fn incorrect_try_expr(
ctx: &DiagnosticsContext<'_>,
d: &hir::IncorrectTryExpr,
) -> Diagnostic {
Diagnostic::new(
"incorrect-try-target",
format!("the return type of the containing function does not implement `FromResidual`"),
ctx.sema
.diagnostics_display_range(InFile::new(d.expr.file_id, d.expr.value.clone().into()))
.range,
)
}
#[cfg(test)]
mod tests {
use crate::tests::check_diagnostics;
#[test]
fn try_ops_diag() {
check_diagnostics(
r#"
//- minicore: try
fn test() {
core::ops::ControlFlow::<u32, f32>::Continue(1.0)?;
// ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ error: the return type of the containing function does not implement `FromResidual`
}
"#,
);
}
}

35
crates/ide-diagnostics/src/handlers/not_implemented.rs Normal file
View file

@ -0,0 +1,35 @@
use hir::{db::DefDatabase, HirDisplay};
use crate::{Diagnostic, DiagnosticsContext};
// Diagnostic: not-implemented
//
// This diagnostic is triggered if a type doesn't implement a necessary trait.
pub(crate) fn not_implemented(ctx: &DiagnosticsContext<'_>, d: &hir::NotImplemented) -> Diagnostic {
Diagnostic::new(
"not-implemented",
format!(
"the trait `{}` is not implemented for `{}`",
ctx.sema.db.trait_data(d.trait_).name,
d.ty.display(ctx.sema.db)
),
ctx.sema.diagnostics_display_range(d.expr.clone().map(|it| it.into())).range,
)
}
#[cfg(test)]
mod tests {
use crate::tests::check_diagnostics;
#[test]
fn missing_try_impl() {
check_diagnostics(
r#"
//- minicore: try
fn main() {
()?;
} //^^ error: the trait `Try` is not implemented for `()`
"#,
)
}
}

4
crates/ide-diagnostics/src/lib.rs
View file

@ -29,6 +29,7 @@ mod handlers {
pub(crate) mod break_outside_of_loop;
pub(crate) mod inactive_code;
pub(crate) mod incorrect_case;
pub(crate) mod incorrect_try_expr;
pub(crate) mod invalid_derive_target;
pub(crate) mod macro_error;
pub(crate) mod malformed_derive;
@ -36,6 +37,7 @@ mod handlers {
pub(crate) mod missing_fields;
pub(crate) mod missing_match_arms;
pub(crate) mod missing_unsafe;
pub(crate) mod not_implemented;
pub(crate) mod no_such_field;
pub(crate) mod replace_filter_map_next_with_find_map;
pub(crate) mod type_mismatch;
@ -225,12 +227,14 @@ pub fn diagnostics(
let d = match diag {
AnyDiagnostic::BreakOutsideOfLoop(d) => handlers::break_outside_of_loop::break_outside_of_loop(&ctx, &d),
AnyDiagnostic::IncorrectCase(d) => handlers::incorrect_case::incorrect_case(&ctx, &d),
AnyDiagnostic::IncorrectTryExpr(d) => handlers::incorrect_try_expr::incorrect_try_expr(&ctx, &d),
AnyDiagnostic::MacroError(d) => handlers::macro_error::macro_error(&ctx, &d),
AnyDiagnostic::MalformedDerive(d) => handlers::malformed_derive::malformed_derive(&ctx, &d),
AnyDiagnostic::MismatchedArgCount(d) => handlers::mismatched_arg_count::mismatched_arg_count(&ctx, &d),
AnyDiagnostic::MissingFields(d) => handlers::missing_fields::missing_fields(&ctx, &d),
AnyDiagnostic::MissingMatchArms(d) => handlers::missing_match_arms::missing_match_arms(&ctx, &d),
AnyDiagnostic::MissingUnsafe(d) => handlers::missing_unsafe::missing_unsafe(&ctx, &d),
AnyDiagnostic::NotImplemented(d) => handlers::not_implemented::not_implemented(&ctx, &d),
AnyDiagnostic::NoSuchField(d) => handlers::no_such_field::no_such_field(&ctx, &d),
AnyDiagnostic::ReplaceFilterMapNextWithFindMap(d) => handlers::replace_filter_map_next_with_find_map::replace_filter_map_next_with_find_map(&ctx, &d),
AnyDiagnostic::TypeMismatch(d) => handlers::type_mismatch::type_mismatch(&ctx, &d),

18
crates/ide/src/hover/tests.rs
View file

@ -4913,6 +4913,22 @@ fn foo() -> NotResult<(), Short> {
```
"#]],
);
check_hover_range(
r#"
//- minicore: try
use core::ops::ControlFlow;
fn foo() -> ControlFlow<()> {
$0ControlFlow::Break(())?$0;
ControlFlow::Continue(())
}
"#,
expect![[r#"
```text
Try Target Type: ControlFlow<(), {unknown}>
Propagated as: ControlFlow<(), ()>
```
"#]],
);
}
#[test]
@ -4929,7 +4945,7 @@ fn foo() -> Option<()> {
"#,
expect![[r#"
```rust
<Option<i32> as Try>::Output
i32
```"#]],
);
}

39
crates/test-utils/src/minicore.rs
View file

@ -27,6 +27,7 @@
//! generator: pin
//! hash:
//! index: sized
//! infallible:
//! iterator: option
//! iterators: iterator, fn
//! option:
@ -36,7 +37,7 @@
//! result:
//! sized:
//! slice:
//! try:
//! try: infallible
//! unsize: sized
pub mod marker {
@ -150,6 +151,9 @@ pub mod convert {
fn as_ref(&self) -> &T;
}
// endregion:as_ref
// region:infallible
pub enum Infallible {}
// endregion:infallible
}
pub mod ops {
@ -326,7 +330,7 @@ pub mod ops {
Continue(C),
Break(B),
}
pub trait FromResidual<R = Self::Residual> {
pub trait FromResidual<R = <Self as Try>::Residual> {
#[lang = "from_residual"]
fn from_residual(residual: R) -> Self;
}
@ -342,13 +346,13 @@ pub mod ops {
impl<B, C> Try for ControlFlow<B, C> {
type Output = C;
type Residual = ControlFlow<B, convert::Infallible>;
type Residual = ControlFlow<B, crate::convert::Infallible>;
fn from_output(output: Self::Output) -> Self {}
fn branch(self) -> ControlFlow<Self::Residual, Self::Output> {}
}
impl<B, C> FromResidual for ControlFlow<B, C> {
fn from_residual(residual: ControlFlow<B, convert::Infallible>) -> Self {}
fn from_residual(residual: ControlFlow<B, crate::convert::Infallible>) -> Self {}
}
}
pub use self::try_::{ControlFlow, FromResidual, Try};
@ -469,6 +473,33 @@ pub mod option {
}
}
}
// region:try
impl<T> crate::ops::Try for Option<T> {
type Output = T;
type Residual = Option<crate::convert::Infallible>;
#[inline]
fn from_output(output: Self::Output) -> Self {
Some(output)
}
#[inline]
fn branch(self) -> crate::ops::ControlFlow<Self::Residual, Self::Output> {
match self {
Some(v) => crate::ops::ControlFlow::Continue(v),
None => crate::ops::ControlFlow::Break(None),
}
}
}
impl<T> crate::ops::FromResidual for Option<T> {
#[inline]
fn from_residual(residual: Option<crate::convert::Infallible>) -> Self {
match residual {
None => None,
}
}
}
// endregion:try
}
// endregion:option