1 files changed, 99 insertions, 0 deletions
diff --git a/src/test/ui/discrim/discrim-overflow.rs b/src/test/ui/discrim/discrim-overflow.rs
new file mode 100644
index 000000000..774ced93c
--- /dev/null
+++ b/src/test/ui/discrim/discrim-overflow.rs
@@ -0,0 +1,99 @@
+// Issue 23030: Detect overflowing discriminant
+
+// See also run-pass/discrim-explicit-23030.rs where the suggested
+// workaround is tested.
+
+fn f_i8() {
+    #[repr(i8)]
+    enum A {
+        Ok = i8::MAX - 1,
+        Ok2,
+        OhNo, //~ ERROR enum discriminant overflowed [E0370]
+    }
+
+    let x = A::Ok;
+}
+
+fn f_u8() {
+    #[repr(u8)]
+    enum A {
+        Ok = u8::MAX - 1,
+        Ok2,
+        OhNo, //~ ERROR enum discriminant overflowed [E0370]
+    }
+
+    let x = A::Ok;
+}
+
+fn f_i16() {
+    #[repr(i16)]
+    enum A {
+        Ok = i16::MAX - 1,
+        Ok2,
+        OhNo, //~ ERROR enum discriminant overflowed [E0370]
+    }
+
+    let x = A::Ok;
+}
+
+fn f_u16() {
+    #[repr(u16)]
+    enum A {
+        Ok = u16::MAX - 1,
+        Ok2,
+        OhNo, //~ ERROR enum discriminant overflowed [E0370]
+              //~| overflowed on value after 65535
+    }
+
+    let x = A::Ok;
+}
+
+fn f_i32() {
+    #[repr(i32)]
+    enum A {
+        Ok = i32::MAX - 1,
+        Ok2,
+        OhNo, //~ ERROR enum discriminant overflowed [E0370]
+              //~| overflowed on value after 2147483647
+    }
+
+    let x = A::Ok;
+}
+
+fn f_u32() {
+    #[repr(u32)]
+    enum A {
+        Ok = u32::MAX - 1,
+        Ok2,
+        OhNo, //~ ERROR enum discriminant overflowed [E0370]
+              //~| overflowed on value after 4294967295
+    }
+
+    let x = A::Ok;
+}
+
+fn f_i64() {
+    #[repr(i64)]
+    enum A {
+        Ok = i64::MAX - 1,
+        Ok2,
+        OhNo, //~ ERROR enum discriminant overflowed [E0370]
+              //~| overflowed on value after 9223372036854775807
+    }
+
+    let x = A::Ok;
+}
+
+fn f_u64() {
+    #[repr(u64)]
+    enum A {
+        Ok = u64::MAX - 1,
+        Ok2,
+        OhNo, //~ ERROR enum discriminant overflowed [E0370]
+              //~| overflowed on value after 18446744073709551615
+    }
+
+    let x = A::Ok;
+}
+
+fn main() { }