Implementation of incompatible features error

If two features are defined as incompatible, using them together would
result in an error

src/test/ui/const-generics/min-and-full-same-time.rs

@@ -0,0 +1,7 @@
+#![feature(const_generics)]
+//~^ ERROR features `const_generics` and `min_const_generics` are incompatible
+#![allow(incomplete_features)]
+#![feature(min_const_generics)]
+
+
+fn main() {}

src/test/ui/const-generics/min-and-full-same-time.stderr

@@ -0,0 +1,13 @@
+error: features `const_generics` and `min_const_generics` are incompatible, using them at the same time is not allowed
+  --> $DIR/min-and-full-same-time.rs:1:12
+   |
+LL | #![feature(const_generics)]
+   |            ^^^^^^^^^^^^^^
+...
+LL | #![feature(min_const_generics)]
+   |            ^^^^^^^^^^^^^^^^^^
+   |
+   = help: remove one of these features
+
+error: aborting due to previous error
+