Try to evaluate constants in legacy mangling

Author: oli-obk

compiler/rustc_symbol_mangling/src/legacy.rs

@@ -2,7 +2,7 @@ use std::fmt::{self, Write};
 use std::mem::{self, discriminant};
 
 use rustc_data_structures::stable_hasher::{Hash64, HashStable, StableHasher};
-use rustc_hir::def_id::CrateNum;
+use rustc_hir::def_id::{CrateNum, DefId};
 use rustc_hir::definitions::{DefPathData, DisambiguatedDefPathData};
 use rustc_middle::bug;
 use rustc_middle::ty::print::{PrettyPrinter, Print, PrintError, Printer};
@@ -378,6 +378,33 @@ impl<'tcx> Printer<'tcx> for SymbolPrinter<'tcx> {
             Ok(())
         }
     }
+
+    fn print_impl_path(
+        &mut self,
+        impl_def_id: DefId,
+        args: &'tcx [GenericArg<'tcx>],
+        mut self_ty: Ty<'tcx>,
+        mut impl_trait_ref: Option<ty::TraitRef<'tcx>>,
+    ) -> Result<(), PrintError> {
+        let mut typing_env = ty::TypingEnv::post_analysis(self.tcx, impl_def_id);
+        if !args.is_empty() {
+            typing_env.param_env =
+                ty::EarlyBinder::bind(typing_env.param_env).instantiate(self.tcx, args);
+        }
+
+        match &mut impl_trait_ref {
+            Some(impl_trait_ref) => {
+                assert_eq!(impl_trait_ref.self_ty(), self_ty);
+                *impl_trait_ref = self.tcx.normalize_erasing_regions(typing_env, *impl_trait_ref);
+                self_ty = impl_trait_ref.self_ty();
+            }
+            None => {
+                self_ty = self.tcx.normalize_erasing_regions(typing_env, self_ty);
+            }
+        }
+
+        self.default_print_impl_path(impl_def_id, args, self_ty, impl_trait_ref)
+    }
 }
 
 impl<'tcx> PrettyPrinter<'tcx> for SymbolPrinter<'tcx> {

tests/ui/symbol-names/types.legacy.stderr

@@ -502,19 +502,19 @@ error: demangling-alt(a::b::Type<[T; N]>)
 LL |     #[rustc_symbol_name]
    |     ^^^^^^^^^^^^^^^^^^^^
 
-error: symbol-name(_ZN1a1b35Type$LT$$u5b$u8$u3b$$u20$_$u5d$$GT$17h[HASH]E)
+error: symbol-name(_ZN1a1b35Type$LT$$u5b$u8$u3b$$u20$0$u5d$$GT$17h[HASH]E)
   --> $DIR/types.rs:272:5
    |
 LL |     #[rustc_symbol_name]
    |     ^^^^^^^^^^^^^^^^^^^^
 
-error: demangling(a::b::Type<[u8; _]>::h[HASH])
+error: demangling(a::b::Type<[u8; 0]>::h[HASH])
   --> $DIR/types.rs:272:5
    |
 LL |     #[rustc_symbol_name]
    |     ^^^^^^^^^^^^^^^^^^^^
 
-error: demangling-alt(a::b::Type<[u8; _]>)
+error: demangling-alt(a::b::Type<[u8; 0]>)
   --> $DIR/types.rs:272:5
    |
 LL |     #[rustc_symbol_name]

tests/ui/symbol-names/types.rs

@@ -270,9 +270,9 @@ pub fn b() {
     const ZERO: usize = 0;
 
     #[rustc_symbol_name]
-    //[legacy,verbose-legacy]~^ ERROR symbol-name(_ZN1a1b35Type$LT$$u5b$u8$u3b$$u20$_$u5d$$GT$
-    //[legacy,verbose-legacy]~| ERROR demangling(a::b::Type<[u8; _]>::
-    //[legacy,verbose-legacy]~| ERROR demangling-alt(a::b::Type<[u8; _]>)
+    //[legacy,verbose-legacy]~^ ERROR symbol-name(_ZN1a1b35Type$LT$$u5b$u8$u3b$$u20$0$u5d$$GT$
+    //[legacy,verbose-legacy]~| ERROR demangling(a::b::Type<[u8; 0]>::
+    //[legacy,verbose-legacy]~| ERROR demangling-alt(a::b::Type<[u8; 0]>)
     //[v0]~^^^^ ERROR symbol-name(_RMsq_NvCsCRATE_HASH_1a1bINtB<REF>_4TypeAhj0_E)
     //[v0]~| ERROR ::b::Type<[u8; 0usize]>>)
     //[v0]~| ERROR demangling-alt(<a::b::Type<[u8; 0]>>)

tests/ui/symbol-names/types.verbose-legacy.stderr

@@ -502,19 +502,19 @@ error: demangling-alt(a::b::Type<[T; N]>)
 LL |     #[rustc_symbol_name]
    |     ^^^^^^^^^^^^^^^^^^^^
 
-error: symbol-name(_ZN1a1b35Type$LT$$u5b$u8$u3b$$u20$_$u5d$$GT$17h[HASH]E)
+error: symbol-name(_ZN1a1b35Type$LT$$u5b$u8$u3b$$u20$0$u5d$$GT$17h[HASH]E)
   --> $DIR/types.rs:272:5
    |
 LL |     #[rustc_symbol_name]
    |     ^^^^^^^^^^^^^^^^^^^^
 
-error: demangling(a::b::Type<[u8; _]>::h[HASH])
+error: demangling(a::b::Type<[u8; 0]>::h[HASH])
   --> $DIR/types.rs:272:5
    |
 LL |     #[rustc_symbol_name]
    |     ^^^^^^^^^^^^^^^^^^^^
 
-error: demangling-alt(a::b::Type<[u8; _]>)
+error: demangling-alt(a::b::Type<[u8; 0]>)
   --> $DIR/types.rs:272:5
    |
 LL |     #[rustc_symbol_name]