const_evaluatable_checked: collect predicates from fn_sig

src/test/ui/const-generics/const_evaluatable_checked/cross_crate_predicate.rs

@@ -8,6 +8,7 @@ fn user<T>() {
     //~^ ERROR constant expression depends
     //~| ERROR constant expression depends
     //~| ERROR constant expression depends
+    //~| ERROR constant expression depends
 }
 
 fn main() {}

src/test/ui/const-generics/const_evaluatable_checked/cross_crate_predicate.stderr

@@ -11,6 +11,19 @@ LL |     [u8; std::mem::size_of::<T>() - 1]: Sized,
    |
    = note: this may fail depending on what value the parameter takes
 
+error: constant expression depends on a generic parameter
+  --> $DIR/cross_crate_predicate.rs:7:13
+   |
+LL |     let _ = const_evaluatable_lib::test1::<T>();
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   | 
+  ::: $DIR/auxiliary/const_evaluatable_lib.rs:6:41
+   |
+LL |     [u8; std::mem::size_of::<T>() - 1]: Sized,
+   |                                         ----- required by this bound in `test1`
+   |
+   = note: this may fail depending on what value the parameter takes
+
 error: constant expression depends on a generic parameter
   --> $DIR/cross_crate_predicate.rs:7:13
    |
@@ -29,8 +42,13 @@ error: constant expression depends on a generic parameter
    |
 LL |     let _ = const_evaluatable_lib::test1::<T>();
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   | 
+  ::: $DIR/auxiliary/const_evaluatable_lib.rs:6:41
+   |
+LL |     [u8; std::mem::size_of::<T>() - 1]: Sized,
+   |                                         ----- required by this bound in `test1::{{constant}}#1`
    |
    = note: this may fail depending on what value the parameter takes
 
-error: aborting due to 3 previous errors
+error: aborting due to 4 previous errors
 

src/test/ui/const-generics/const_evaluatable_checked/from-sig-fail.rs

@@ -0,0 +1,11 @@
+#![feature(const_generics, const_evaluatable_checked)]
+#![allow(incomplete_features)]
+
+fn test<const N: usize>() -> [u8; N - 1] {
+    //~^ ERROR evaluation of constant
+    todo!()
+}
+
+fn main() {
+    test::<0>();
+}

src/test/ui/const-generics/const_evaluatable_checked/from-sig-fail.stderr

@@ -0,0 +1,9 @@
+error[E0080]: evaluation of constant value failed
+  --> $DIR/from-sig-fail.rs:4:35
+   |
+LL | fn test<const N: usize>() -> [u8; N - 1] {
+   |                                   ^^^^^ attempt to compute `0_usize - 1_usize` which would overflow
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0080`.

src/test/ui/const-generics/const_evaluatable_checked/from-sig.rs

@@ -0,0 +1,14 @@
+// run-pass
+#![feature(const_generics, const_evaluatable_checked)]
+#![allow(incomplete_features)]
+
+struct Foo<const B: bool>;
+
+fn test<const N: usize>() -> Foo<{ N > 10 }> {
+    Foo
+}
+
+fn main() {
+    let _: Foo<true> = test::<12>();
+    let _: Foo<false> = test::<9>();
+}