diff --git a/src/librustc_typeck/check/expr.rs b/src/librustc_typeck/check/expr.rs index 9680f61d69903..d139cd4264c86 100644 --- a/src/librustc_typeck/check/expr.rs +++ b/src/librustc_typeck/check/expr.rs @@ -24,6 +24,7 @@ use syntax::source_map::Span; use syntax::util::lev_distance::find_best_match_for_name; use rustc::hir; use rustc::hir::{ExprKind, QPath}; +use rustc::hir::def_id::DefId; use rustc::hir::def::{CtorKind, Res, DefKind}; use rustc::hir::ptr::P; use rustc::infer; @@ -1336,116 +1337,182 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> { autoderef.unambiguous_final_ty(self); if let Some((did, field_ty)) = private_candidate { - let struct_path = self.tcx().def_path_str(did); - let mut err = struct_span_err!(self.tcx().sess, expr.span, E0616, - "field `{}` of struct `{}` is private", - field, struct_path); - // Also check if an accessible method exists, which is often what is meant. - if self.method_exists(field, expr_t, expr.hir_id, false) - && !self.expr_in_place(expr.hir_id) - { - self.suggest_method_call( - &mut err, - &format!("a method `{}` also exists, call it with parentheses", field), - field, - expr_t, - expr.hir_id, - ); - } - err.emit(); - field_ty - } else if field.name == kw::Invalid { - self.tcx().types.err + self.ban_private_field_access(expr, expr_t, field, did); + return field_ty; + } + + if field.name == kw::Invalid { } else if self.method_exists(field, expr_t, expr.hir_id, true) { - let mut err = type_error_struct!(self.tcx().sess, field.span, expr_t, E0615, - "attempted to take value of method `{}` on type `{}`", - field, expr_t); - - if !self.expr_in_place(expr.hir_id) { - self.suggest_method_call( - &mut err, - "use parentheses to call the method", - field, - expr_t, - expr.hir_id - ); - } else { - err.help("methods are immutable and cannot be assigned to"); + self.ban_take_value_of_method(expr, expr_t, field); + } else if !expr_t.is_primitive_ty() { + let mut err = self.no_such_field_err(field.span, field, expr_t); + + match expr_t.sty { + ty::Adt(def, _) if !def.is_enum() => { + self.suggest_fields_on_recordish(&mut err, def, field); + } + ty::Array(_, len) => { + self.maybe_suggest_array_indexing(&mut err, expr, base, field, len); + } + ty::RawPtr(..) => { + self.suggest_first_deref_field(&mut err, expr, base, field); + } + _ => {} + } + + if field.name == kw::Await { + // We know by construction that `.await` is either on Rust 2015 + // or results in `ExprKind::Await`. Suggest switching the edition to 2018. + err.note("to `.await` a `Future`, switch to Rust 2018"); + err.help("set `edition = \"2018\"` in `Cargo.toml`"); + err.note("for more on editions, read https://doc.rust-lang.org/edition-guide"); } err.emit(); - self.tcx().types.err } else { - if !expr_t.is_primitive_ty() { - let mut err = self.no_such_field_err(field.span, field, expr_t); - - match expr_t.sty { - ty::Adt(def, _) if !def.is_enum() => { - if let Some(suggested_field_name) = - Self::suggest_field_name(def.non_enum_variant(), - &field.as_str(), vec![]) { - err.span_suggestion( - field.span, - "a field with a similar name exists", - suggested_field_name.to_string(), - Applicability::MaybeIncorrect, - ); - } else { - err.span_label(field.span, "unknown field"); - let struct_variant_def = def.non_enum_variant(); - let field_names = self.available_field_names(struct_variant_def); - if !field_names.is_empty() { - err.note(&format!("available fields are: {}", - self.name_series_display(field_names))); - } - }; - } - ty::Array(_, len) => { - if let (Some(len), Ok(user_index)) = ( - len.try_eval_usize(self.tcx, self.param_env), - field.as_str().parse::() - ) { - let base = self.tcx.sess.source_map() - .span_to_snippet(base.span) - .unwrap_or_else(|_| - self.tcx.hir().hir_to_pretty_string(base.hir_id)); - let help = "instead of using tuple indexing, use array indexing"; - let suggestion = format!("{}[{}]", base, field); - let applicability = if len < user_index { - Applicability::MachineApplicable - } else { - Applicability::MaybeIncorrect - }; - err.span_suggestion( - expr.span, help, suggestion, applicability - ); - } - } - ty::RawPtr(..) => { - let base = self.tcx.sess.source_map() - .span_to_snippet(base.span) - .unwrap_or_else(|_| self.tcx.hir().hir_to_pretty_string(base.hir_id)); - let msg = format!("`{}` is a raw pointer; try dereferencing it", base); - let suggestion = format!("(*{}).{}", base, field); - err.span_suggestion( - expr.span, - &msg, - suggestion, - Applicability::MaybeIncorrect, - ); - } - _ => {} - } - err + type_error_struct!( + self.tcx().sess, + field.span, + expr_t, + E0610, + "`{}` is a primitive type and therefore doesn't have fields", + expr_t + ) + .emit(); + } + + self.tcx().types.err + } + + fn ban_private_field_access( + &self, + expr: &hir::Expr, + expr_t: Ty<'tcx>, + field: ast::Ident, + base_did: DefId, + ) { + let struct_path = self.tcx().def_path_str(base_did); + let mut err = struct_span_err!( + self.tcx().sess, + expr.span, + E0616, + "field `{}` of struct `{}` is private", + field, + struct_path + ); + // Also check if an accessible method exists, which is often what is meant. + if self.method_exists(field, expr_t, expr.hir_id, false) + && !self.expr_in_place(expr.hir_id) + { + self.suggest_method_call( + &mut err, + &format!("a method `{}` also exists, call it with parentheses", field), + field, + expr_t, + expr.hir_id, + ); + } + err.emit(); + } + + fn ban_take_value_of_method(&self, expr: &hir::Expr, expr_t: Ty<'tcx>, field: ast::Ident) { + let mut err = type_error_struct!( + self.tcx().sess, + field.span, + expr_t, + E0615, + "attempted to take value of method `{}` on type `{}`", + field, + expr_t + ); + + if !self.expr_in_place(expr.hir_id) { + self.suggest_method_call( + &mut err, + "use parentheses to call the method", + field, + expr_t, + expr.hir_id + ); + } else { + err.help("methods are immutable and cannot be assigned to"); + } + + err.emit(); + } + + fn suggest_fields_on_recordish( + &self, + err: &mut DiagnosticBuilder<'_>, + def: &'tcx ty::AdtDef, + field: ast::Ident, + ) { + if let Some(suggested_field_name) = + Self::suggest_field_name(def.non_enum_variant(), &field.as_str(), vec![]) + { + err.span_suggestion( + field.span, + "a field with a similar name exists", + suggested_field_name.to_string(), + Applicability::MaybeIncorrect, + ); + } else { + err.span_label(field.span, "unknown field"); + let struct_variant_def = def.non_enum_variant(); + let field_names = self.available_field_names(struct_variant_def); + if !field_names.is_empty() { + err.note(&format!("available fields are: {}", + self.name_series_display(field_names))); + } + } + } + + fn maybe_suggest_array_indexing( + &self, + err: &mut DiagnosticBuilder<'_>, + expr: &hir::Expr, + base: &hir::Expr, + field: ast::Ident, + len: &ty::Const<'tcx>, + ) { + if let (Some(len), Ok(user_index)) = ( + len.try_eval_usize(self.tcx, self.param_env), + field.as_str().parse::() + ) { + let base = self.tcx.sess.source_map() + .span_to_snippet(base.span) + .unwrap_or_else(|_| self.tcx.hir().hir_to_pretty_string(base.hir_id)); + let help = "instead of using tuple indexing, use array indexing"; + let suggestion = format!("{}[{}]", base, field); + let applicability = if len < user_index { + Applicability::MachineApplicable } else { - type_error_struct!(self.tcx().sess, field.span, expr_t, E0610, - "`{}` is a primitive type and therefore doesn't have fields", - expr_t) - }.emit(); - self.tcx().types.err + Applicability::MaybeIncorrect + }; + err.span_suggestion(expr.span, help, suggestion, applicability); } } + fn suggest_first_deref_field( + &self, + err: &mut DiagnosticBuilder<'_>, + expr: &hir::Expr, + base: &hir::Expr, + field: ast::Ident, + ) { + let base = self.tcx.sess.source_map() + .span_to_snippet(base.span) + .unwrap_or_else(|_| self.tcx.hir().hir_to_pretty_string(base.hir_id)); + let msg = format!("`{}` is a raw pointer; try dereferencing it", base); + let suggestion = format!("(*{}).{}", base, field); + err.span_suggestion( + expr.span, + &msg, + suggestion, + Applicability::MaybeIncorrect, + ); + } + fn no_such_field_err(&self, span: Span, field: T, expr_t: &ty::TyS<'_>) -> DiagnosticBuilder<'_> { type_error_struct!(self.tcx().sess, span, expr_t, E0609, diff --git a/src/test/ui/async-await/suggest-switching-edition-on-await.rs b/src/test/ui/async-await/suggest-switching-edition-on-await.rs new file mode 100644 index 0000000000000..1402f1ca92ba8 --- /dev/null +++ b/src/test/ui/async-await/suggest-switching-edition-on-await.rs @@ -0,0 +1,45 @@ +use std::pin::Pin; +use std::future::Future; + +fn main() {} + +fn await_on_struct_missing() { + struct S; + let x = S; + x.await; + //~^ ERROR no field `await` on type + //~| NOTE unknown field + //~| NOTE to `.await` a `Future`, switch to Rust 2018 + //~| HELP set `edition = "2018"` in `Cargo.toml` + //~| NOTE for more on editions, read https://doc.rust-lang.org/edition-guide +} + +fn await_on_struct_similar() { + struct S { + awai: u8, + } + let x = S { awai: 42 }; + x.await; + //~^ ERROR no field `await` on type + //~| HELP a field with a similar name exists + //~| NOTE to `.await` a `Future`, switch to Rust 2018 + //~| HELP set `edition = "2018"` in `Cargo.toml` + //~| NOTE for more on editions, read https://doc.rust-lang.org/edition-guide +} + +fn await_on_63533(x: Pin<&mut dyn Future>) { + x.await; + //~^ ERROR no field `await` on type + //~| NOTE unknown field + //~| NOTE to `.await` a `Future`, switch to Rust 2018 + //~| HELP set `edition = "2018"` in `Cargo.toml` + //~| NOTE for more on editions, read https://doc.rust-lang.org/edition-guide +} + +fn await_on_apit(x: impl Future) { + x.await; + //~^ ERROR no field `await` on type + //~| NOTE to `.await` a `Future`, switch to Rust 2018 + //~| HELP set `edition = "2018"` in `Cargo.toml` + //~| NOTE for more on editions, read https://doc.rust-lang.org/edition-guide +} diff --git a/src/test/ui/async-await/suggest-switching-edition-on-await.stderr b/src/test/ui/async-await/suggest-switching-edition-on-await.stderr new file mode 100644 index 0000000000000..f623511c0eb23 --- /dev/null +++ b/src/test/ui/async-await/suggest-switching-edition-on-await.stderr @@ -0,0 +1,43 @@ +error[E0609]: no field `await` on type `await_on_struct_missing::S` + --> $DIR/suggest-switching-edition-on-await.rs:9:7 + | +LL | x.await; + | ^^^^^ unknown field + | + = note: to `.await` a `Future`, switch to Rust 2018 + = help: set `edition = "2018"` in `Cargo.toml` + = note: for more on editions, read https://doc.rust-lang.org/edition-guide + +error[E0609]: no field `await` on type `await_on_struct_similar::S` + --> $DIR/suggest-switching-edition-on-await.rs:22:7 + | +LL | x.await; + | ^^^^^ help: a field with a similar name exists: `awai` + | + = note: to `.await` a `Future`, switch to Rust 2018 + = help: set `edition = "2018"` in `Cargo.toml` + = note: for more on editions, read https://doc.rust-lang.org/edition-guide + +error[E0609]: no field `await` on type `std::pin::Pin<&mut dyn std::future::Future>` + --> $DIR/suggest-switching-edition-on-await.rs:31:7 + | +LL | x.await; + | ^^^^^ unknown field + | + = note: to `.await` a `Future`, switch to Rust 2018 + = help: set `edition = "2018"` in `Cargo.toml` + = note: for more on editions, read https://doc.rust-lang.org/edition-guide + +error[E0609]: no field `await` on type `impl Future` + --> $DIR/suggest-switching-edition-on-await.rs:40:7 + | +LL | x.await; + | ^^^^^ + | + = note: to `.await` a `Future`, switch to Rust 2018 + = help: set `edition = "2018"` in `Cargo.toml` + = note: for more on editions, read https://doc.rust-lang.org/edition-guide + +error: aborting due to 4 previous errors + +For more information about this error, try `rustc --explain E0609`.