Don't detect fn consts as generic consts

Author: saethlin

compiler/rustc_mir_transform/src/lib.rs

@@ -855,7 +855,7 @@ impl<'tcx> Visitor<'tcx> for MonoCompatVisitor {
     }
 
     fn visit_const_operand(&mut self, constant: &ConstOperand<'tcx>, location: Location) {
-        if constant.has_non_region_param() {
+        if constant.has_non_region_param() && !constant.ty().is_fn() {
             self.contains_generic_const = true;
         }
         self.super_const_operand(constant, location);

tests/codegen/array-cmp.rs

@@ -67,7 +67,7 @@ pub fn array_of_tuple_le(a: &[(i16, u16); 2], b: &[(i16, u16); 2]) -> bool {
     // CHECK-NEXT: br i1 %[[EQ11]], label %[[DONE:.+]], label %[[EXIT_U]]
 
     // CHECK: [[DONE]]:
-    // CHECK: %[[RET:.+]] = phi i1 [ %{{.+}}, %[[EXIT_U]] ], [ %{{.+}}, %[[EXIT_S]] ], [ true, %[[L11]] ]
+    // CHECK: %[[RET:.+]] = phi i1 [ %{{.+}}, %[[EXIT_S]] ], [ %{{.+}}, %[[EXIT_U]] ], [ true, %[[L11]] ]
     // CHECK: ret i1 %[[RET]]
 
     a <= b

tests/ui/layout/post-mono-layout-cycle.stderr

@@ -5,11 +5,11 @@ error[E0391]: cycle detected when computing layout of `Wrapper<()>`
    = note: cycle used when computing layout of `core::option::Option<Wrapper<()>>`
    = note: see https://rustc-dev-guide.rust-lang.org/overview.html#queries and https://rustc-dev-guide.rust-lang.org/query.html for more information
 
-note: the above error was encountered while instantiating `fn indirect::<()>`
-  --> $DIR/post-mono-layout-cycle.rs:23:5
+note: the above error was encountered while instantiating `fn abi::<()>`
+  --> $DIR/post-mono-layout-cycle.rs:19:5
    |
-LL |     indirect::<()>();
-   |     ^^^^^^^^^^^^^^^^
+LL |     abi::<T>(None);
+   |     ^^^^^^^^^^^^^^
 
 error: aborting due to 1 previous error