Add tests

4 files changed, 229 insertions, 0 deletions

diff --git a/src/test/ui/pattern/usefulness/match-empty-exhaustive_patterns.rs b/src/test/ui/pattern/usefulness/match-empty-exhaustive_patterns.rs
new file mode 100644
index 00000000000..0a8194253a3
--- /dev/null
+++ b/src/test/ui/pattern/usefulness/match-empty-exhaustive_patterns.rs
@@ -0,0 +1,46 @@
+#![feature(never_type)]
+#![feature(exhaustive_patterns)]
+#![deny(unreachable_patterns)]
+enum Foo {}
+
+struct NonEmptyStruct(bool);
+enum NonEmptyEnum1 {
+    Foo(bool),
+}
+enum NonEmptyEnum2 {
+    Foo(bool),
+    Bar,
+}
+enum NonEmptyEnum5 {
+    V1, V2, V3, V4, V5,
+}
+
+fn foo(x: Foo) {
+    match x {} // ok
+    match x {
+        _ => {}, //~ ERROR unreachable pattern
+    }
+}
+
+fn main() {
+    // `exhaustive_patterns` is not on, so uninhabited branches are not detected as unreachable.
+    match None::<!> {
+        None => {}
+        Some(_) => {} //~ ERROR unreachable pattern
+    }
+    match None::<Foo> {
+        None => {}
+        Some(_) => {} //~ ERROR unreachable pattern
+    }
+
+    match 0u8 {}
+    //~^ ERROR type `u8` is non-empty
+    match NonEmptyStruct(true) {}
+    //~^ ERROR type `NonEmptyStruct` is non-empty
+    match NonEmptyEnum1::Foo(true) {}
+    //~^ ERROR type `NonEmptyEnum1` is non-empty
+    match NonEmptyEnum2::Foo(true) {}
+    //~^ ERROR type `NonEmptyEnum2` is non-empty
+    match NonEmptyEnum5::V1 {}
+    //~^ ERROR type `NonEmptyEnum5` is non-empty
+}
diff --git a/src/test/ui/pattern/usefulness/match-empty-exhaustive_patterns.stderr b/src/test/ui/pattern/usefulness/match-empty-exhaustive_patterns.stderr
new file mode 100644
index 00000000000..8d143494026
--- /dev/null
+++ b/src/test/ui/pattern/usefulness/match-empty-exhaustive_patterns.stderr
@@ -0,0 +1,67 @@
+error: unreachable pattern
+  --> $DIR/match-empty-exhaustive_patterns.rs:21:9
+   |
+LL |         _ => {},
+   |         ^
+   |
+note: lint level defined here
+  --> $DIR/match-empty-exhaustive_patterns.rs:3:9
+   |
+LL | #![deny(unreachable_patterns)]
+   |         ^^^^^^^^^^^^^^^^^^^^
+
+error: unreachable pattern
+  --> $DIR/match-empty-exhaustive_patterns.rs:29:9
+   |
+LL |         Some(_) => {}
+   |         ^^^^^^^
+
+error: unreachable pattern
+  --> $DIR/match-empty-exhaustive_patterns.rs:33:9
+   |
+LL |         Some(_) => {}
+   |         ^^^^^^^
+
+error[E0004]: non-exhaustive patterns: type `u8` is non-empty
+  --> $DIR/match-empty-exhaustive_patterns.rs:36:11
+   |
+LL |     match 0u8 {}
+   |           ^^^
+   |
+   = help: ensure that all possible cases are being handled, possibly by adding wildcards or more match arms
+
+error[E0004]: non-exhaustive patterns: type `NonEmptyStruct` is non-empty
+  --> $DIR/match-empty-exhaustive_patterns.rs:38:11
+   |
+LL |     match NonEmptyStruct(true) {}
+   |           ^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: ensure that all possible cases are being handled, possibly by adding wildcards or more match arms
+
+error[E0004]: non-exhaustive patterns: type `NonEmptyEnum1` is non-empty
+  --> $DIR/match-empty-exhaustive_patterns.rs:40:11
+   |
+LL |     match NonEmptyEnum1::Foo(true) {}
+   |           ^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: ensure that all possible cases are being handled, possibly by adding wildcards or more match arms
+
+error[E0004]: non-exhaustive patterns: type `NonEmptyEnum2` is non-empty
+  --> $DIR/match-empty-exhaustive_patterns.rs:42:11
+   |
+LL |     match NonEmptyEnum2::Foo(true) {}
+   |           ^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: ensure that all possible cases are being handled, possibly by adding wildcards or more match arms
+
+error[E0004]: non-exhaustive patterns: type `NonEmptyEnum5` is non-empty
+  --> $DIR/match-empty-exhaustive_patterns.rs:44:11
+   |
+LL |     match NonEmptyEnum5::V1 {}
+   |           ^^^^^^^^^^^^^^^^^
+   |
+   = help: ensure that all possible cases are being handled, possibly by adding wildcards or more match arms
+
+error: aborting due to 8 previous errors
+
+For more information about this error, try `rustc --explain E0004`.
diff --git a/src/test/ui/pattern/usefulness/match-empty.rs b/src/test/ui/pattern/usefulness/match-empty.rs
new file mode 100644
index 00000000000..28ebde6c4c1
--- /dev/null
+++ b/src/test/ui/pattern/usefulness/match-empty.rs
@@ -0,0 +1,48 @@
+#![feature(never_type)]
+#![deny(unreachable_patterns)]
+enum Foo {}
+
+struct NonEmptyStruct(bool); //~ `NonEmptyStruct` defined here
+enum NonEmptyEnum1 { //~ `NonEmptyEnum1` defined here
+    Foo(bool), //~ variant not covered
+}
+enum NonEmptyEnum2 { //~ `NonEmptyEnum2` defined here
+    Foo(bool), //~ variant not covered
+    Bar, //~ variant not covered
+}
+enum NonEmptyEnum5 { //~ `NonEmptyEnum5` defined here
+    V1, V2, V3, V4, V5,
+}
+
+fn foo1(x: Foo) {
+    match x {} // ok
+}
+
+fn foo2(x: Foo) {
+    match x {
+        _ => {}, // FIXME: should be unreachable
+    }
+}
+
+fn main() {
+    // `exhaustive_patterns` is not on, so uninhabited branches are not detected as unreachable.
+    match None::<!> {
+        None => {}
+        Some(_) => {}
+    }
+    match None::<Foo> {
+        None => {}
+        Some(_) => {}
+    }
+
+    match 0u8 {}
+    //~^ ERROR type `u8` is non-empty
+    match NonEmptyStruct(true) {}
+    //~^ ERROR pattern `NonEmptyStruct` of type `NonEmptyStruct` is not handled
+    match NonEmptyEnum1::Foo(true) {}
+    //~^ ERROR pattern `Foo` of type `NonEmptyEnum1` is not handled
+    match NonEmptyEnum2::Foo(true) {}
+    //~^ ERROR multiple patterns of type `NonEmptyEnum2` are not handled
+    match NonEmptyEnum5::V1 {}
+    //~^ ERROR type `NonEmptyEnum5` is non-empty
+}
diff --git a/src/test/ui/pattern/usefulness/match-empty.stderr b/src/test/ui/pattern/usefulness/match-empty.stderr
new file mode 100644
index 00000000000..eb6cfaa61df
--- /dev/null
+++ b/src/test/ui/pattern/usefulness/match-empty.stderr
@@ -0,0 +1,68 @@
+error[E0004]: non-exhaustive patterns: type `u8` is non-empty
+  --> $DIR/match-empty.rs:38:11
+   |
+LL |     match 0u8 {}
+   |           ^^^
+   |
+   = help: ensure that all possible cases are being handled, possibly by adding wildcards or more match arms
+
+error[E0004]: non-exhaustive patterns: pattern `NonEmptyStruct` of type `NonEmptyStruct` is not handled
+  --> $DIR/match-empty.rs:40:11
+   |
+LL | struct NonEmptyStruct(bool);
+   | ----------------------------
+   | |      |
+   | |      variant not covered
+   | `NonEmptyStruct` defined here
+...
+LL |     match NonEmptyStruct(true) {}
+   |           ^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: ensure that all possible cases are being handled, possibly by adding wildcards or more match arms
+
+error[E0004]: non-exhaustive patterns: pattern `Foo` of type `NonEmptyEnum1` is not handled
+  --> $DIR/match-empty.rs:42:11
+   |
+LL | / enum NonEmptyEnum1 {
+LL | |     Foo(bool),
+   | |     --- variant not covered
+LL | | }
+   | |_- `NonEmptyEnum1` defined here
+...
+LL |       match NonEmptyEnum1::Foo(true) {}
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: ensure that all possible cases are being handled, possibly by adding wildcards or more match arms
+
+error[E0004]: non-exhaustive patterns: multiple patterns of type `NonEmptyEnum2` are not handled
+  --> $DIR/match-empty.rs:44:11
+   |
+LL | / enum NonEmptyEnum2 {
+LL | |     Foo(bool),
+   | |     --- variant not covered
+LL | |     Bar,
+   | |     --- variant not covered
+LL | | }
+   | |_- `NonEmptyEnum2` defined here
+...
+LL |       match NonEmptyEnum2::Foo(true) {}
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: ensure that all possible cases are being handled, possibly by adding wildcards or more match arms
+
+error[E0004]: non-exhaustive patterns: type `NonEmptyEnum5` is non-empty
+  --> $DIR/match-empty.rs:46:11
+   |
+LL | / enum NonEmptyEnum5 {
+LL | |     V1, V2, V3, V4, V5,
+LL | | }
+   | |_- `NonEmptyEnum5` defined here
+...
+LL |       match NonEmptyEnum5::V1 {}
+   |             ^^^^^^^^^^^^^^^^^
+   |
+   = help: ensure that all possible cases are being handled, possibly by adding wildcards or more match arms
+
+error: aborting due to 5 previous errors
+
+For more information about this error, try `rustc --explain E0004`.