Print constness in TraitPredPrintModifiersAndPath

Author: compiler-errors

compiler/rustc_middle/src/ty/print/pretty.rs

@@ -2880,11 +2880,15 @@ define_print_and_forward_display! {
     }
 
     TraitPredPrintModifiersAndPath<'tcx> {
-        // FIXME(effects) print `~const` here
+        if let Some(idx) = cx.tcx().generics_of(self.0.trait_ref.def_id).host_effect_index
+        {
+            if self.0.trait_ref.args.const_at(idx) != cx.tcx().consts.true_ {
+                p!("~const ");
+            }
+        }
         if let ty::ImplPolarity::Negative = self.0.polarity {
             p!("!")
         }
-
         p!(print(self.0.trait_ref.print_only_trait_path()));
     }
 
@@ -2919,7 +2923,6 @@ define_print_and_forward_display! {
                 p!("~const ");
             }
         }
-        // FIXME(effects) print `~const` here
         if let ty::ImplPolarity::Negative = self.polarity {
             p!("!");
         }

tests/ui/rfcs/rfc-2632-const-trait-impl/call-const-trait-method-fail.stderr

@@ -2,7 +2,7 @@ error[E0277]: the trait bound `u32: ~const Plus` is not satisfied
   --> $DIR/call-const-trait-method-fail.rs:25:5
    |
 LL |     a.plus(b)
-   |     ^ the trait `Plus` is not implemented for `u32`
+   |     ^ the trait `~const Plus` is not implemented for `u32`
    |
    = help: the trait `Plus` is implemented for `u32`
 

tests/ui/rfcs/rfc-2632-const-trait-impl/call-generic-method-nonconst.stderr

@@ -2,7 +2,7 @@ error[E0277]: the trait bound `S: ~const Foo` is not satisfied
   --> $DIR/call-generic-method-nonconst.rs:23:34
    |
 LL | pub const EQ: bool = equals_self(&S);
-   |                      ----------- ^^ the trait `Foo` is not implemented for `S`
+   |                      ----------- ^^ the trait `~const Foo` is not implemented for `S`
    |                      |
    |                      required by a bound introduced by this call
    |

tests/ui/rfcs/rfc-2632-const-trait-impl/const-default-method-bodies.stderr

@@ -2,7 +2,7 @@ error[E0277]: the trait bound `NonConstImpl: ~const ConstDefaultFn` is not satis
   --> $DIR/const-default-method-bodies.rs:24:18
    |
 LL |     NonConstImpl.a();
-   |                  ^ the trait `ConstDefaultFn` is not implemented for `NonConstImpl`
+   |                  ^ the trait `~const ConstDefaultFn` is not implemented for `NonConstImpl`
    |
    = help: the trait `ConstDefaultFn` is implemented for `NonConstImpl`
 

tests/ui/rfcs/rfc-2632-const-trait-impl/cross-crate.gatednc.stderr

@@ -2,7 +2,7 @@ error[E0277]: the trait bound `cross_crate::NonConst: ~const cross_crate::MyTrai
   --> $DIR/cross-crate.rs:17:14
    |
 LL |     NonConst.func();
-   |              ^^^^ the trait `cross_crate::MyTrait` is not implemented for `cross_crate::NonConst`
+   |              ^^^^ the trait `~const cross_crate::MyTrait` is not implemented for `cross_crate::NonConst`
    |
    = help: the trait `cross_crate::MyTrait` is implemented for `cross_crate::NonConst`
 

tests/ui/rfcs/rfc-2632-const-trait-impl/default-method-body-is-const-same-trait-ck.stderr

@@ -2,7 +2,7 @@ error[E0277]: the trait bound `(): ~const Tr` is not satisfied
   --> $DIR/default-method-body-is-const-same-trait-ck.rs:8:12
    |
 LL |         ().a()
-   |            ^ the trait `Tr` is not implemented for `()`
+   |            ^ the trait `~const Tr` is not implemented for `()`
    |
    = help: the trait `Tr` is implemented for `()`