Mark all missing generic args as errors

Author: oli-obk

compiler/rustc_hir_analysis/src/hir_ty_lowering/mod.rs

@@ -422,6 +422,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
             span: Span,
             inferred_params: Vec<Span>,
             infer_args: bool,
+            incorrect_args: &'a Result<(), GenericArgCountMismatch>,
         }
 
         impl<'a, 'tcx> GenericArgsLowerer<'a, 'tcx> for GenericArgsCtxt<'a, 'tcx> {
@@ -508,6 +509,25 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
                 infer_args: bool,
             ) -> ty::GenericArg<'tcx> {
                 let tcx = self.lowerer.tcx();
+
+                if let Err(incorrect) = self.incorrect_args {
+                    if incorrect.invalid_args.contains(&(param.index as usize)) {
+                        return match param.kind {
+                            GenericParamDefKind::Lifetime => {
+                                ty::Region::new_error(tcx, incorrect.reported).into()
+                            }
+                            GenericParamDefKind::Type { .. } => {
+                                Ty::new_error(tcx, incorrect.reported).into()
+                            }
+                            GenericParamDefKind::Const { .. } => ty::Const::new_error(
+                                tcx,
+                                incorrect.reported,
+                                Ty::new_error(tcx, incorrect.reported),
+                            )
+                            .into(),
+                        };
+                    }
+                }
                 match param.kind {
                     GenericParamDefKind::Lifetime => self
                         .lowerer
@@ -568,15 +588,6 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
                 }
             }
         }
-
-        let mut args_ctx = GenericArgsCtxt {
-            lowerer: self,
-            def_id,
-            span,
-            generic_args: segment.args(),
-            inferred_params: vec![],
-            infer_args: segment.infer_args,
-        };
         if let ty::BoundConstness::Const | ty::BoundConstness::ConstIfConst = constness
             && generics.has_self
             && !tcx.has_attr(def_id, sym::const_trait)
@@ -588,6 +599,16 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
             self.set_tainted_by_errors(reported);
             arg_count.correct = Err(GenericArgCountMismatch { reported, invalid_args: vec![] });
         }
+
+        let mut args_ctx = GenericArgsCtxt {
+            lowerer: self,
+            def_id,
+            span,
+            generic_args: segment.args(),
+            inferred_params: vec![],
+            infer_args: segment.infer_args,
+            incorrect_args: &arg_count.correct,
+        };
         let args = lower_generic_args(
             tcx,
             def_id,

tests/crashes/123917.rs

@@ -24,7 +24,6 @@ fn via_associated_const() {
     trait Trait {
         const FALSE: bool = assert::is_transmutable::<Src, Dst, Context, {}>();
         //~^ ERROR mismatched types
-        //~| ERROR `Src` cannot be safely transmuted into `Dst`
         //~| ERROR mismatched types
     }
 }

tests/ui/const-generics/adt_const_params/transmutable-ice-110969.rs

@@ -12,28 +12,13 @@ error[E0308]: mismatched types
 LL |         const FALSE: bool = assert::is_transmutable::<Src, Dst, Context, {}>();
    |                                                                          ^^ expected `Assume`, found `()`
 
-error[E0277]: `Src` cannot be safely transmuted into `Dst`
-  --> $DIR/transmutable-ice-110969.rs:25:60
-   |
-LL |         const FALSE: bool = assert::is_transmutable::<Src, Dst, Context, {}>();
-   |                                                            ^^^ `Dst` may carry safety invariants
-   |
-note: required by a bound in `is_transmutable`
-  --> $DIR/transmutable-ice-110969.rs:11:14
-   |
-LL |     pub fn is_transmutable<Src, Dst, Context, const ASSUME: std::mem::Assume>()
-   |            --------------- required by a bound in this function
-LL |     where
-LL |         Dst: BikeshedIntrinsicFrom<Src, Context, ASSUME>,
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_transmutable`
-
 error[E0308]: mismatched types
   --> $DIR/transmutable-ice-110969.rs:25:29
    |
 LL |         const FALSE: bool = assert::is_transmutable::<Src, Dst, Context, {}>();
    |                             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected `bool`, found `()`
 
-error: aborting due to 4 previous errors
+error: aborting due to 3 previous errors
 
-Some errors have detailed explanations: E0107, E0277, E0308.
+Some errors have detailed explanations: E0107, E0308.
 For more information about an error, try `rustc --explain E0107`.

tests/ui/const-generics/adt_const_params/transmutable-ice-110969.stderr

@@ -0,0 +1,20 @@
+//! This test used to ICE: #123917
+//! The reason was that while the AST knows about two fields
+//! named `ptr`, only one exists at the layout level, so accessing
+//! `_extra_field` would use an oob index
+//@ compile-flags: -Zmir-opt-level=5 -Zpolymorphize=on
+
+struct NonNull<T>(*mut T);
+
+struct Token<T> {
+    ptr: *mut T,
+    ptr: NonNull<T>,
+    //~^ ERROR: `ptr` is already declared
+    _extra_field: (),
+}
+
+fn tokenize<T>(item: *mut T) -> Token<T> {
+    Token { ptr: NonNull(item), _extra_field: () }
+}
+
+fn main() {}

tests/ui/polymorphization/abi_mismatch.rs

@@ -0,0 +1,11 @@
+error[E0124]: field `ptr` is already declared
+  --> $DIR/abi_mismatch.rs:11:5
+   |
+LL |     ptr: *mut T,
+   |     ----------- `ptr` first declared here
+LL |     ptr: NonNull<T>,
+   |     ^^^^^^^^^^^^^^^ field already declared
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0124`.