diff --git a/crates/hir-ty/src/diagnostics/expr.rs b/crates/hir-ty/src/diagnostics/expr.rs index afb80e1f4450..0c5d6399619a 100644 --- a/crates/hir-ty/src/diagnostics/expr.rs +++ b/crates/hir-ty/src/diagnostics/expr.rs @@ -12,6 +12,7 @@ use hir_expand::name; use itertools::Itertools; use rustc_hash::FxHashSet; use rustc_pattern_analysis::usefulness::{compute_match_usefulness, ValidityConstraint}; +use tracing::debug; use triomphe::Arc; use typed_arena::Arena; @@ -44,6 +45,10 @@ pub enum BodyValidationDiagnostic { match_expr: ExprId, uncovered_patterns: String, }, + NonExhaustiveLet { + pat: PatId, + uncovered_patterns: String, + }, RemoveTrailingReturn { return_expr: ExprId, }, @@ -68,7 +73,7 @@ struct ExprValidator { owner: DefWithBodyId, body: Arc, infer: Arc, - pub(super) diagnostics: Vec, + diagnostics: Vec, } impl ExprValidator { @@ -105,6 +110,9 @@ impl ExprValidator { Expr::If { .. } => { self.check_for_unnecessary_else(id, expr, &body); } + Expr::Block { .. } => { + self.validate_block(db, expr); + } _ => {} } } @@ -231,11 +239,55 @@ impl ExprValidator { if !witnesses.is_empty() { self.diagnostics.push(BodyValidationDiagnostic::MissingMatchArms { match_expr, - uncovered_patterns: missing_match_arms(&cx, scrut_ty, witnesses, arms), + uncovered_patterns: missing_match_arms(&cx, scrut_ty, witnesses, m_arms.is_empty()), }); } } + fn validate_block(&mut self, db: &dyn HirDatabase, expr: &Expr) { + let Expr::Block { statements, .. } = expr else { return }; + let pattern_arena = Arena::new(); + let cx = MatchCheckCtx::new(self.owner.module(db.upcast()), self.owner, db); + for stmt in &**statements { + let &Statement::Let { pat, initializer, else_branch: None, .. } = stmt else { + continue; + }; + let Some(initializer) = initializer else { continue }; + let ty = &self.infer[initializer]; + + let mut have_errors = false; + let deconstructed_pat = self.lower_pattern(&cx, pat, db, &mut have_errors); + let match_arm = rustc_pattern_analysis::MatchArm { + pat: pattern_arena.alloc(deconstructed_pat), + has_guard: false, + arm_data: (), + }; + if have_errors { + continue; + } + + let report = match compute_match_usefulness( + &cx, + &[match_arm], + ty.clone(), + ValidityConstraint::ValidOnly, + ) { + Ok(v) => v, + Err(e) => { + debug!(?e, "match usefulness error"); + continue; + } + }; + let witnesses = report.non_exhaustiveness_witnesses; + if !witnesses.is_empty() { + self.diagnostics.push(BodyValidationDiagnostic::NonExhaustiveLet { + pat, + uncovered_patterns: missing_match_arms(&cx, ty, witnesses, false), + }); + } + } + } + fn lower_pattern<'p>( &self, cx: &MatchCheckCtx<'p>, @@ -444,7 +496,7 @@ fn missing_match_arms<'p>( cx: &MatchCheckCtx<'p>, scrut_ty: &Ty, witnesses: Vec>, - arms: &[MatchArm], + arms_is_empty: bool, ) -> String { struct DisplayWitness<'a, 'p>(&'a WitnessPat<'p>, &'a MatchCheckCtx<'p>); impl fmt::Display for DisplayWitness<'_, '_> { @@ -459,7 +511,7 @@ fn missing_match_arms<'p>( Some((AdtId::EnumId(e), _)) => !cx.db.enum_data(e).variants.is_empty(), _ => false, }; - if arms.is_empty() && !non_empty_enum { + if arms_is_empty && !non_empty_enum { format!("type `{}` is non-empty", scrut_ty.display(cx.db)) } else { let pat_display = |witness| DisplayWitness(witness, cx); diff --git a/crates/hir/src/diagnostics.rs b/crates/hir/src/diagnostics.rs index 08843a6c9994..d351e257d2e7 100644 --- a/crates/hir/src/diagnostics.rs +++ b/crates/hir/src/diagnostics.rs @@ -64,6 +64,7 @@ diagnostics![ MissingUnsafe, MovedOutOfRef, NeedMut, + NonExhaustiveLet, NoSuchField, PrivateAssocItem, PrivateField, @@ -280,6 +281,12 @@ pub struct MissingMatchArms { pub uncovered_patterns: String, } +#[derive(Debug)] +pub struct NonExhaustiveLet { + pub pat: InFile>, + pub uncovered_patterns: String, +} + #[derive(Debug)] pub struct TypeMismatch { pub expr_or_pat: InFile>>, @@ -456,6 +463,22 @@ impl AnyDiagnostic { Err(SyntheticSyntax) => (), } } + BodyValidationDiagnostic::NonExhaustiveLet { pat, uncovered_patterns } => { + match source_map.pat_syntax(pat) { + Ok(source_ptr) => { + if let Some(ast_pat) = source_ptr.value.cast::() { + return Some( + NonExhaustiveLet { + pat: InFile::new(source_ptr.file_id, ast_pat), + uncovered_patterns, + } + .into(), + ); + } + } + Err(SyntheticSyntax) => {} + } + } BodyValidationDiagnostic::RemoveTrailingReturn { return_expr } => { if let Ok(source_ptr) = source_map.expr_syntax(return_expr) { // Filters out desugared return expressions (e.g. desugared try operators). diff --git a/crates/ide-diagnostics/src/handlers/mutability_errors.rs b/crates/ide-diagnostics/src/handlers/mutability_errors.rs index bdb55a9d98a2..3c71f84dc485 100644 --- a/crates/ide-diagnostics/src/handlers/mutability_errors.rs +++ b/crates/ide-diagnostics/src/handlers/mutability_errors.rs @@ -817,7 +817,7 @@ fn f() { //- minicore: option fn f(_: i32) {} fn main() { - let ((Some(mut x), None) | (_, Some(mut x))) = (None, Some(7)); + let ((Some(mut x), None) | (_, Some(mut x))) = (None, Some(7)) else { return }; //^^^^^ 💡 warn: variable does not need to be mutable f(x); } diff --git a/crates/ide-diagnostics/src/handlers/non_exhaustive_let.rs b/crates/ide-diagnostics/src/handlers/non_exhaustive_let.rs new file mode 100644 index 000000000000..1a4d2877ef25 --- /dev/null +++ b/crates/ide-diagnostics/src/handlers/non_exhaustive_let.rs @@ -0,0 +1,47 @@ +use crate::{Diagnostic, DiagnosticCode, DiagnosticsContext}; + +// Diagnostic: non-exhaustive-let +// +// This diagnostic is triggered if a `let` statement without an `else` branch has a non-exhaustive +// pattern. +pub(crate) fn non_exhaustive_let( + ctx: &DiagnosticsContext<'_>, + d: &hir::NonExhaustiveLet, +) -> Diagnostic { + Diagnostic::new_with_syntax_node_ptr( + ctx, + DiagnosticCode::RustcHardError("E0005"), + format!("non-exhaustive pattern: {}", d.uncovered_patterns), + d.pat.map(Into::into), + ) +} + +#[cfg(test)] +mod tests { + use crate::tests::check_diagnostics; + + #[test] + fn option_nonexhaustive() { + check_diagnostics( + r#" +//- minicore: option +fn main() { + let None = Some(5); + //^^^^ error: non-exhaustive pattern: `Some(_)` not covered +} +"#, + ); + } + + #[test] + fn option_exhaustive() { + check_diagnostics( + r#" +//- minicore: option +fn main() { + let Some(_) | None = Some(5); +} +"#, + ); + } +} diff --git a/crates/ide-diagnostics/src/lib.rs b/crates/ide-diagnostics/src/lib.rs index 9d21bb4cd9fb..3a3888011d75 100644 --- a/crates/ide-diagnostics/src/lib.rs +++ b/crates/ide-diagnostics/src/lib.rs @@ -41,6 +41,7 @@ mod handlers { pub(crate) mod moved_out_of_ref; pub(crate) mod mutability_errors; pub(crate) mod no_such_field; + pub(crate) mod non_exhaustive_let; pub(crate) mod private_assoc_item; pub(crate) mod private_field; pub(crate) mod remove_trailing_return; @@ -359,6 +360,7 @@ pub fn diagnostics( AnyDiagnostic::MissingUnsafe(d) => handlers::missing_unsafe::missing_unsafe(&ctx, &d), AnyDiagnostic::MovedOutOfRef(d) => handlers::moved_out_of_ref::moved_out_of_ref(&ctx, &d), AnyDiagnostic::NeedMut(d) => handlers::mutability_errors::need_mut(&ctx, &d), + AnyDiagnostic::NonExhaustiveLet(d) => handlers::non_exhaustive_let::non_exhaustive_let(&ctx, &d), AnyDiagnostic::NoSuchField(d) => handlers::no_such_field::no_such_field(&ctx, &d), AnyDiagnostic::PrivateAssocItem(d) => handlers::private_assoc_item::private_assoc_item(&ctx, &d), AnyDiagnostic::PrivateField(d) => handlers::private_field::private_field(&ctx, &d),