diff options
| -rw-r--r-- | compiler/rustc_hir_typeck/src/demand.rs | 3 | ||||
| -rw-r--r-- | compiler/rustc_hir_typeck/src/expr.rs | 12 | ||||
| -rw-r--r-- | compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs | 49 | ||||
| -rw-r--r-- | src/test/ui/suggestions/option-to-bool.rs | 9 | ||||
| -rw-r--r-- | src/test/ui/suggestions/option-to-bool.stderr | 16 |
5 files changed, 85 insertions, 4 deletions
diff --git a/compiler/rustc_hir_typeck/src/demand.rs b/compiler/rustc_hir_typeck/src/demand.rs index 16febfc46da..7f78f5fb8a7 100644 --- a/compiler/rustc_hir_typeck/src/demand.rs +++ b/compiler/rustc_hir_typeck/src/demand.rs @@ -42,7 +42,8 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> { || self.suggest_boxing_when_appropriate(err, expr, expected, expr_ty) || self.suggest_block_to_brackets_peeling_refs(err, expr, expr_ty, expected) || self.suggest_copied_or_cloned(err, expr, expr_ty, expected) - || self.suggest_into(err, expr, expr_ty, expected); + || self.suggest_into(err, expr, expr_ty, expected) + || self.suggest_option_to_bool(err, expr, expr_ty, expected); self.note_type_is_not_clone(err, expected, expr_ty, expr); self.note_need_for_fn_pointer(err, expected, expr_ty); diff --git a/compiler/rustc_hir_typeck/src/expr.rs b/compiler/rustc_hir_typeck/src/expr.rs index 43669489e69..e948d832e32 100644 --- a/compiler/rustc_hir_typeck/src/expr.rs +++ b/compiler/rustc_hir_typeck/src/expr.rs @@ -103,8 +103,16 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> { } if let Some(mut err) = self.demand_suptype_diag(expr.span, expected_ty, ty) { - let expr = expr.peel_drop_temps(); - self.suggest_deref_ref_or_into(&mut err, expr, expected_ty, ty, None); + // FIXME(compiler-errors): We probably should fold some of the + // `suggest_` functions from `emit_coerce_suggestions` into here, + // since some of those aren't necessarily just coerce suggestions. + let _ = self.suggest_deref_ref_or_into( + &mut err, + expr.peel_drop_temps(), + expected_ty, + ty, + None, + ) || self.suggest_option_to_bool(&mut err, expr, ty, expected_ty); extend_err(&mut err); err.emit(); } diff --git a/compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs b/compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs index e3b3fb499b1..a14759e254c 100644 --- a/compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs +++ b/compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs @@ -13,7 +13,7 @@ use rustc_hir_analysis::astconv::AstConv; use rustc_infer::infer::{self, TyCtxtInferExt}; use rustc_infer::traits::{self, StatementAsExpression}; use rustc_middle::lint::in_external_macro; -use rustc_middle::ty::{self, Binder, IsSuggestable, ToPredicate, Ty}; +use rustc_middle::ty::{self, Binder, DefIdTree, IsSuggestable, ToPredicate, Ty}; use rustc_session::errors::ExprParenthesesNeeded; use rustc_span::symbol::sym; use rustc_span::Span; @@ -1116,6 +1116,53 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> { false } + /// When expecting a `bool` and finding an `Option`, suggests using `let Some(..)` or `.is_some()` + pub(crate) fn suggest_option_to_bool( + &self, + diag: &mut Diagnostic, + expr: &hir::Expr<'_>, + expr_ty: Ty<'tcx>, + expected_ty: Ty<'tcx>, + ) -> bool { + if !expected_ty.is_bool() { + return false; + } + + let ty::Adt(def, _) = expr_ty.peel_refs().kind() else { return false; }; + if !self.tcx.is_diagnostic_item(sym::Option, def.did()) { + return false; + } + + let hir = self.tcx.hir(); + let cond_parent = hir.parent_iter(expr.hir_id).skip_while(|(_, node)| { + matches!(node, hir::Node::Expr(hir::Expr { kind: hir::ExprKind::Binary(op, _, _), .. }) if op.node == hir::BinOpKind::And) + }).next(); + // Don't suggest: + // `let Some(_) = a.is_some() && b` + // ++++++++++ + // since the user probably just misunderstood how `let else` + // and `&&` work together. + if let Some((_, hir::Node::Local(local))) = cond_parent + && let hir::PatKind::Path(qpath) | hir::PatKind::TupleStruct(qpath, _, _) = &local.pat.kind + && let hir::QPath::Resolved(None, path) = qpath + && let Some(did) = path.res.opt_def_id() + .and_then(|did| self.tcx.opt_parent(did)) + .and_then(|did| self.tcx.opt_parent(did)) + && self.tcx.is_diagnostic_item(sym::Option, did) + { + return false; + } + + diag.span_suggestion( + expr.span.shrink_to_hi(), + "use `Option::is_some` to test if the `Option` has a value", + ".is_some()", + Applicability::MachineApplicable, + ); + + true + } + /// Suggest wrapping the block in square brackets instead of curly braces /// in case the block was mistaken array syntax, e.g. `{ 1 }` -> `[ 1 ]`. pub(crate) fn suggest_block_to_brackets( diff --git a/src/test/ui/suggestions/option-to-bool.rs b/src/test/ui/suggestions/option-to-bool.rs new file mode 100644 index 00000000000..2a1823b15f5 --- /dev/null +++ b/src/test/ui/suggestions/option-to-bool.rs @@ -0,0 +1,9 @@ +#![cfg_attr(let_chains, feature(let_chains))] + +fn foo(x: Option<i32>) { + if true && x {} + //~^ ERROR mismatched types + //~| HELP use `Option::is_some` to test if the `Option` has a value +} + +fn main() {} diff --git a/src/test/ui/suggestions/option-to-bool.stderr b/src/test/ui/suggestions/option-to-bool.stderr new file mode 100644 index 00000000000..57a934b8342 --- /dev/null +++ b/src/test/ui/suggestions/option-to-bool.stderr @@ -0,0 +1,16 @@ +error[E0308]: mismatched types + --> $DIR/option-to-bool.rs:4:16 + | +LL | if true && x {} + | ^ expected `bool`, found enum `Option` + | + = note: expected type `bool` + found enum `Option<i32>` +help: use `Option::is_some` to test if the `Option` has a value + | +LL | if true && x.is_some() {} + | ++++++++++ + +error: aborting due to previous error + +For more information about this error, try `rustc --explain E0308`. |