From d6d77e8a35cb2ac63b877f73bdf0ea6e6a1578e4 Mon Sep 17 00:00:00 2001
From: Dawer <7803845+iDawer@users.noreply.github.com>
Date: Thu, 6 May 2021 17:26:05 +0500
Subject: [PATCH] Treat ctor of unhandled type as non-exhaustive.

---
 crates/hir_ty/src/diagnostics/pattern.rs       | 18 ++++++++++++++++++
 .../src/diagnostics/pattern/deconstruct_pat.rs | 10 ++++++----
 2 files changed, 24 insertions(+), 4 deletions(-)

diff --git a/crates/hir_ty/src/diagnostics/pattern.rs b/crates/hir_ty/src/diagnostics/pattern.rs
index 5c9419d2cca..7b0b63d0bfa 100644
--- a/crates/hir_ty/src/diagnostics/pattern.rs
+++ b/crates/hir_ty/src/diagnostics/pattern.rs
@@ -353,6 +353,24 @@ fn main() {
         //^^^^ Missing match arm
 
 }
+"#,
+        );
+    }
+
+    #[test]
+    fn no_panic_at_unimplemented_subpattern_type() {
+        check_diagnostics(
+            r#"
+struct S { a: char}
+fn main(v: S) {
+    match v { S{ a }      => {} }
+    match v { S{ a: x }   => {} }
+    match v { S{ a: 'a' } => {} }
+    match v { S{..}       => {} }
+    match v { _           => {} }
+    match v { }
+        //^ Missing match arm
+}
 "#,
         );
     }
diff --git a/crates/hir_ty/src/diagnostics/pattern/deconstruct_pat.rs b/crates/hir_ty/src/diagnostics/pattern/deconstruct_pat.rs
index ddf6b1198f7..1319745ce14 100644
--- a/crates/hir_ty/src/diagnostics/pattern/deconstruct_pat.rs
+++ b/crates/hir_ty/src/diagnostics/pattern/deconstruct_pat.rs
@@ -419,6 +419,8 @@ impl SplitWildcard {
         let cx = pcx.cx;
         let make_range =
             |start, end, scalar| IntRange(IntRange::from_range(cx, start, end, scalar));
+        // FIXME(iDawer) using NonExhaustive ctor for unhandled types
+        let unhandled = || smallvec![NonExhaustive];
 
         // This determines the set of all possible constructors for the type `pcx.ty`. For numbers,
         // arrays and slices we use ranges and variable-length slices when appropriate.
@@ -431,7 +433,7 @@ impl SplitWildcard {
         let all_ctors = match pcx.ty.kind(&Interner) {
             TyKind::Scalar(Scalar::Bool) => smallvec![make_range(0, 1, Scalar::Bool)],
             // TyKind::Array(..) if ... => todo!(),
-            TyKind::Array(..) | TyKind::Slice(..) => todo!(),
+            TyKind::Array(..) | TyKind::Slice(..) => unhandled(),
             &TyKind::Adt(AdtId(hir_def::AdtId::EnumId(enum_id)), ref _substs) => {
                 let enum_data = cx.db.enum_data(enum_id);
 
@@ -466,7 +468,7 @@ impl SplitWildcard {
                 } else if cx.feature_exhaustive_patterns() {
                     // If `exhaustive_patterns` is enabled, we exclude variants known to be
                     // uninhabited.
-                    todo!()
+                    unhandled()
                 } else {
                     enum_data
                         .variants
@@ -475,8 +477,8 @@ impl SplitWildcard {
                         .collect()
                 }
             }
-            TyKind::Scalar(Scalar::Char) => todo!(),
-            TyKind::Scalar(Scalar::Int(..)) | TyKind::Scalar(Scalar::Uint(..)) => todo!(),
+            TyKind::Scalar(Scalar::Char) => unhandled(),
+            TyKind::Scalar(Scalar::Int(..)) | TyKind::Scalar(Scalar::Uint(..)) => unhandled(),
             TyKind::Never if !cx.feature_exhaustive_patterns() && !pcx.is_top_level => {
                 smallvec![NonExhaustive]
             }