Fix generic arg mismatch errors being ignored with explicit late bound lifetimes

compiler/rustc_typeck/src/astconv/generics.rs

@@ -264,9 +264,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                                 // another. This is an error. However, if we already know that
                                 // the arguments don't match up with the parameters, we won't issue
                                 // an additional error, as the user already knows what's wrong.
-                                if arg_count.correct.is_ok()
-                                    && arg_count.explicit_late_bound == ExplicitLateBound::No
-                                {
+                                if arg_count.correct.is_ok() {
                                     // We're going to iterate over the parameters to sort them out, and
                                     // show that order to the user as a possible order for the parameters
                                     let mut param_types_present = defs
@@ -446,7 +444,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                 }
 
                 if silent {
-                    return false;
+                    return true;
                 }
 
                 if provided > expected_max {

compiler/rustc_typeck/src/check/fn_ctxt/_impl.rs

@@ -1282,6 +1282,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
 
         let mut infer_args_for_err = FxHashSet::default();
 
+        let mut explicit_late_bound = ExplicitLateBound::No;
         for &PathSeg(def_id, index) in &path_segs {
             let seg = &segments[index];
             let generics = tcx.generics_of(def_id);
@@ -1290,17 +1291,20 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             // parameter internally, but we don't allow users to specify the
             // parameter's value explicitly, so we have to do some error-
             // checking here.
-            if let GenericArgCountResult {
-                correct: Err(GenericArgCountMismatch { reported: Some(_), .. }),
-                ..
-            } = <dyn AstConv<'_>>::check_generic_arg_count_for_call(
+            let arg_count = <dyn AstConv<'_>>::check_generic_arg_count_for_call(
                 tcx,
                 span,
                 def_id,
                 &generics,
                 seg,
                 IsMethodCall::No,
-            ) {
+            );
+
+            if let ExplicitLateBound::Yes = arg_count.explicit_late_bound {
+                explicit_late_bound = ExplicitLateBound::Yes;
+            }
+
+            if let Err(GenericArgCountMismatch { reported: Some(_), .. }) = arg_count.correct {
                 infer_args_for_err.insert(index);
                 self.set_tainted_by_errors(); // See issue #53251.
             }
@@ -1357,7 +1361,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         let ty = tcx.type_of(def_id);
 
         let arg_count = GenericArgCountResult {
-            explicit_late_bound: ExplicitLateBound::No,
+            explicit_late_bound,
             correct: if infer_args_for_err.is_empty() {
                 Ok(())
             } else {

src/test/ui/const-generics/issues/issue-83466.rs

@@ -0,0 +1,17 @@
+// regression test for #83466- tests that generic arg mismatch errors between
+// consts and types are not supressed when there are explicit late bound lifetimes
+
+struct S;
+impl S {
+    fn func<'a, U>(self) -> U {
+        todo!()
+    }
+}
+fn dont_crash<'a, U>() {
+    S.func::<'a, 10_u32>()
+    //~^ WARNING cannot specify lifetime arguments explicitly if late bound lifetime parameters are present
+    //~^^ WARNING this was previously accepted by
+    //~^^^ ERROR constant provided when a type was expected [E0747]
+}
+
+fn main() {}

src/test/ui/const-generics/issues/issue-83466.stderr

@@ -0,0 +1,22 @@
+warning: cannot specify lifetime arguments explicitly if late bound lifetime parameters are present
+  --> $DIR/issue-83466.rs:11:14
+   |
+LL |     fn func<'a, U>(self) -> U {
+   |             -- the late bound lifetime parameter is introduced here
+...
+LL |     S.func::<'a, 10_u32>()
+   |              ^^
+   |
+   = note: `#[warn(late_bound_lifetime_arguments)]` on by default
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #42868 <https://github.com/rust-lang/rust/issues/42868>
+
+error[E0747]: constant provided when a type was expected
+  --> $DIR/issue-83466.rs:11:18
+   |
+LL |     S.func::<'a, 10_u32>()
+   |                  ^^^^^^
+
+error: aborting due to previous error; 1 warning emitted
+
+For more information about this error, try `rustc --explain E0747`.