3 files changed, 85 insertions, 30 deletions
diff --git a/crates/hir_ty/src/diagnostics/expr.rs b/crates/hir_ty/src/diagnostics/expr.rs
index 929c4a9cc..e4e9ab5c0 100644
--- a/crates/hir_ty/src/diagnostics/expr.rs
+++ b/crates/hir_ty/src/diagnostics/expr.rs
@@ -379,32 +379,58 @@ impl<'a, 'b> ExprValidator<'a, 'b> {
        let (body, source_map): (Arc<Body>, Arc<BodySourceMap>) =
            db.body_with_source_map(self.owner);
-        let _match_expr_ty = if infer.type_of_expr[match_expr].is_unknown() {
+        let match_expr_ty = if infer.type_of_expr[match_expr].is_unknown() {
            return;
        } else {
            &infer.type_of_expr[match_expr]
        };
-        // eprintln!("ExprValidator::validate_match2({:?})", _match_expr_ty.kind(&Interner));
        let pattern_arena = RefCell::new(PatternArena::new());
-        let mut have_errors = false;
+        let mut m_arms = Vec::new();
-        let m_arms: Vec<_> = arms
+        let mut has_lowering_errors = false;
-            .iter()
+        for arm in arms {
-            .map(|arm| usefulness::MatchArm {
+            if let Some(pat_ty) = infer.type_of_pat.get(arm.pat) {
-                pat: self.lower_pattern(
+                // We only include patterns whose type matches the type
-                    arm.pat,
+                // of the match expression. If we had a InvalidMatchArmPattern
-                    &mut pattern_arena.borrow_mut(),
+                // diagnostic or similar we could raise that in an else
-                    db,
+                // block here.
-                    &body,
+                //
-                    &mut have_errors,
+                // When comparing the types, we also have to consider that rustc
-                ),
+                // will automatically de-reference the match expression type if
-                has_guard: arm.guard.is_some(),
+                // necessary.
-            })
+                //
-            .collect();
+                // FIXME we should use the type checker for this.
+                if pat_ty == match_expr_ty
-        // Bail out early if lowering failed.
+                    || match_expr_ty
-        if have_errors {
+                        .as_reference()
+                        .map(|(match_expr_ty, ..)| match_expr_ty == pat_ty)
+                        .unwrap_or(false)
+                {
+                    // If we had a NotUsefulMatchArm diagnostic, we could
+                    // check the usefulness of each pattern as we added it
+                    // to the matrix here.
+                    let m_arm = usefulness::MatchArm {
+                        pat: self.lower_pattern(
+                            arm.pat,
+                            &mut pattern_arena.borrow_mut(),
+                            db,
+                            &body,
+                            &mut has_lowering_errors,
+                        ),
+                        has_guard: arm.guard.is_some(),
+                    };
+                    m_arms.push(m_arm);
+                    if !has_lowering_errors {
+                        continue;
+                    }
+                }
+            }
+            // If we can't resolve the type of a pattern, or the pattern type doesn't
+            // fit the match expression, we skip this diagnostic. Skipping the entire
+            // diagnostic rather than just not including this match arm is preferred
+            // to avoid the chance of false positives.
            return;
        }
@@ -418,18 +444,11 @@ impl<'a, 'b> ExprValidator<'a, 'b> {
        };
        let report = usefulness::compute_match_usefulness(&cx, &m_arms);
-        // TODO Report unreacheble arms
+        // FIXME Report unreacheble arms
-        // let mut catchall = None;
+        // https://github.com/rust-lang/rust/blob/25c15cdbe/compiler/rustc_mir_build/src/thir/pattern/check_match.rs#L200-L201
-        // for (arm_index, (arm, is_useful)) in report.arm_usefulness.iter().enumerate() {
-        //     match is_useful{
-        //         Unreachable => {
-        //         }
-        //         Reachable(_) => {}
-        //     }
-        // }
        let witnesses = report.non_exhaustiveness_witnesses;
-        eprintln!("compute_match_usefulness(..) -> {:?}", &witnesses);
+        // eprintln!("compute_match_usefulness(..) -> {:?}", &witnesses);
        if !witnesses.is_empty() {
            if let Ok(source_ptr) = source_map.expr_syntax(id) {
                let root = source_ptr.file_syntax(db.upcast());
diff --git a/crates/hir_ty/src/diagnostics/pattern.rs b/crates/hir_ty/src/diagnostics/pattern.rs
index d98fb0867..38e4b53b7 100644
--- a/crates/hir_ty/src/diagnostics/pattern.rs
+++ b/crates/hir_ty/src/diagnostics/pattern.rs
@@ -511,4 +511,40 @@ fn main() {
 "#,
        );
    }
+    /// These failing tests are narrowed down from "hir_ty::diagnostics::match_check::tests"
+    // TODO fix
+    mod failing {
+        use super::*;
+        #[test]
+        fn never() {
+            check_diagnostics(
+                r#"
+enum Never {}
+fn enum_ref(never: &Never) {
+    match never {}
+}
+"#,
+            );
+        }
+        #[test]
+        fn unknown_type() {
+            check_diagnostics(
+                r#"
+enum Option<T> { Some(T), None }
+fn main() {
+    // `Never` is deliberately not defined so that it's an uninferred type.
+    match Option::<Never>::None {
+        None => {}
+        Some(never) => {}
+    }
+}
+"#,
+            );
+        }
+    }
 }
diff --git a/crates/hir_ty/src/diagnostics/pattern/usefulness.rs b/crates/hir_ty/src/diagnostics/pattern/usefulness.rs
index ef2be7530..01a7fb0d9 100644
--- a/crates/hir_ty/src/diagnostics/pattern/usefulness.rs
+++ b/crates/hir_ty/src/diagnostics/pattern/usefulness.rs
@@ -28,7 +28,7 @@ pub(crate) struct MatchCheckCtx<'a> {
    pub(crate) body: Arc<Body>,
    pub(crate) infer: &'a InferenceResult,
    pub(crate) db: &'a dyn HirDatabase,
-    /// Patterns from self.body.pats plus generated by the check.
+    /// Lowered patterns from self.body.pats plus generated by the check.
    pub(crate) pattern_arena: &'a RefCell<PatternArena>,
 }

diff --git a/crates/hir_ty/src/diagnostics/expr.rs b/crates/hir_ty/src/diagnostics/expr.rs index 929c4a9cc..e4e9ab5c0 100644 --- a/crates/hir_ty/src/diagnostics/expr.rs +++ b/crates/hir_ty/src/diagnostics/expr.rs
@@ -379,32 +379,58 @@ impl<'a, 'b> ExprValidator<'a, 'b> {
379	let (body, source_map): (Arc<Body>, Arc<BodySourceMap>) =	379	let (body, source_map): (Arc<Body>, Arc<BodySourceMap>) =
380	db.body_with_source_map(self.owner);	380	db.body_with_source_map(self.owner);
381		381
382	let _match_expr_ty = if infer.type_of_expr[match_expr].is_unknown() {	382	let match_expr_ty = if infer.type_of_expr[match_expr].is_unknown() {
383	return;	383	return;
384	} else {	384	} else {
385	&infer.type_of_expr[match_expr]	385	&infer.type_of_expr[match_expr]
386	};	386	};
387	// eprintln!("ExprValidator::validate_match2({:?})", _match_expr_ty.kind(&Interner));
388		387
389	let pattern_arena = RefCell::new(PatternArena::new());	388	let pattern_arena = RefCell::new(PatternArena::new());
390		389
391	let mut have_errors = false;	390	let mut m_arms = Vec::new();
392	let m_arms: Vec<_> = arms	391	let mut has_lowering_errors = false;
393	.iter()	392	for arm in arms {
394	.map(\|arm\| usefulness::MatchArm {	393	if let Some(pat_ty) = infer.type_of_pat.get(arm.pat) {
395	pat: self.lower_pattern(	394	// We only include patterns whose type matches the type
396	arm.pat,	395	// of the match expression. If we had a InvalidMatchArmPattern
397	&mut pattern_arena.borrow_mut(),	396	// diagnostic or similar we could raise that in an else
398	db,	397	// block here.
399	&body,	398	//
400	&mut have_errors,	399	// When comparing the types, we also have to consider that rustc
401	),	400	// will automatically de-reference the match expression type if
402	has_guard: arm.guard.is_some(),	401	// necessary.
403	})	402	//
404	.collect();	403	// FIXME we should use the type checker for this.
405		404	if pat_ty == match_expr_ty
406	// Bail out early if lowering failed.	405	\|\| match_expr_ty
407	if have_errors {	406	.as_reference()
		407	.map(\|(match_expr_ty, ..)\| match_expr_ty == pat_ty)
		408	.unwrap_or(false)
		409	{
		410	// If we had a NotUsefulMatchArm diagnostic, we could
		411	// check the usefulness of each pattern as we added it
		412	// to the matrix here.
		413	let m_arm = usefulness::MatchArm {
		414	pat: self.lower_pattern(
		415	arm.pat,
		416	&mut pattern_arena.borrow_mut(),
		417	db,
		418	&body,
		419	&mut has_lowering_errors,
		420	),
		421	has_guard: arm.guard.is_some(),
		422	};
		423	m_arms.push(m_arm);
		424	if !has_lowering_errors {
		425	continue;
		426	}
		427	}
		428	}
		429
		430	// If we can't resolve the type of a pattern, or the pattern type doesn't
		431	// fit the match expression, we skip this diagnostic. Skipping the entire
		432	// diagnostic rather than just not including this match arm is preferred
		433	// to avoid the chance of false positives.
408	return;	434	return;
409	}	435	}
410		436
@@ -418,18 +444,11 @@ impl<'a, 'b> ExprValidator<'a, 'b> {
418	};	444	};
419	let report = usefulness::compute_match_usefulness(&cx, &m_arms);	445	let report = usefulness::compute_match_usefulness(&cx, &m_arms);
420		446
421	// TODO Report unreacheble arms	447	// FIXME Report unreacheble arms
422	// let mut catchall = None;	448	// https://github.com/rust-lang/rust/blob/25c15cdbe/compiler/rustc_mir_build/src/thir/pattern/check_match.rs#L200-L201
423	// for (arm_index, (arm, is_useful)) in report.arm_usefulness.iter().enumerate() {
424	// match is_useful{
425	// Unreachable => {
426	// }
427	// Reachable(_) => {}
428	// }
429	// }
430		449
431	let witnesses = report.non_exhaustiveness_witnesses;	450	let witnesses = report.non_exhaustiveness_witnesses;
432	eprintln!("compute_match_usefulness(..) -> {:?}", &witnesses);	451	// eprintln!("compute_match_usefulness(..) -> {:?}", &witnesses);
433	if !witnesses.is_empty() {	452	if !witnesses.is_empty() {
434	if let Ok(source_ptr) = source_map.expr_syntax(id) {	453	if let Ok(source_ptr) = source_map.expr_syntax(id) {
435	let root = source_ptr.file_syntax(db.upcast());	454	let root = source_ptr.file_syntax(db.upcast());


diff --git a/crates/hir_ty/src/diagnostics/pattern.rs b/crates/hir_ty/src/diagnostics/pattern.rs index d98fb0867..38e4b53b7 100644 --- a/crates/hir_ty/src/diagnostics/pattern.rs +++ b/crates/hir_ty/src/diagnostics/pattern.rs
@@ -511,4 +511,40 @@ fn main() {
511	"#,	511	"#,
512	);	512	);
513	}	513	}
		514
		515	/// These failing tests are narrowed down from "hir_ty::diagnostics::match_check::tests"
		516	// TODO fix
		517	mod failing {
		518	use super::*;
		519
		520	#[test]
		521	fn never() {
		522	check_diagnostics(
		523	r#"
		524	enum Never {}
		525
		526	fn enum_ref(never: &Never) {
		527	match never {}
		528	}
		529	"#,
		530	);
		531	}
		532
		533	#[test]
		534	fn unknown_type() {
		535	check_diagnostics(
		536	r#"
		537	enum Option<T> { Some(T), None }
		538
		539	fn main() {
		540	// `Never` is deliberately not defined so that it's an uninferred type.
		541	match Option::<Never>::None {
		542	None => {}
		543	Some(never) => {}
		544	}
		545	}
		546	"#,
		547	);
		548	}
		549	}
514	}	550	}


diff --git a/crates/hir_ty/src/diagnostics/pattern/usefulness.rs b/crates/hir_ty/src/diagnostics/pattern/usefulness.rs index ef2be7530..01a7fb0d9 100644 --- a/crates/hir_ty/src/diagnostics/pattern/usefulness.rs +++ b/crates/hir_ty/src/diagnostics/pattern/usefulness.rs
@@ -28,7 +28,7 @@ pub(crate) struct MatchCheckCtx<'a> {
28	pub(crate) body: Arc<Body>,	28	pub(crate) body: Arc<Body>,
29	pub(crate) infer: &'a InferenceResult,	29	pub(crate) infer: &'a InferenceResult,
30	pub(crate) db: &'a dyn HirDatabase,	30	pub(crate) db: &'a dyn HirDatabase,
31	/// Patterns from self.body.pats plus generated by the check.	31	/// Lowered patterns from self.body.pats plus generated by the check.
32	pub(crate) pattern_arena: &'a RefCell<PatternArena>,	32	pub(crate) pattern_arena: &'a RefCell<PatternArena>,
33	}	33	}
34		34