Don't abort early when collecting const generics

src/librustc_typeck/collect.rs

@@ -1053,12 +1053,13 @@ fn generics_of<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> &'tcx ty
                         );
                     }
 
+                    // Emit an error, but skip the parameter rather than aborting to
+                    // continue to get other errors.
                     tcx.sess.struct_span_err(
                         param.span,
                         "const generics in any position are currently unsupported",
                     ).emit();
-                    tcx.sess.abort_if_errors();
-                    bug!();
+                    None
                 }
                 _ => None,
             }),

src/test/ui/const-generics/const-param-before-other-params.rs

@@ -8,6 +8,7 @@ fn foo<const X: (), T>(_: T) {
 
 fn bar<const X: (), 'a>(_: &'a ()) {
     //~^ ERROR lifetime parameters must be declared prior to const parameters
+    //~^^ ERROR const generics in any position are currently unsupported
 }
 
 fn main() {}

src/test/ui/const-generics/const-param-before-other-params.stderr

@@ -22,5 +22,11 @@ error: const generics in any position are currently unsupported
 LL | fn foo<const X: (), T>(_: T) {
    |              ^
 
-error: aborting due to 3 previous errors
+error: const generics in any position are currently unsupported
+  --> $DIR/const-param-before-other-params.rs:9:14
+   |
+LL | fn bar<const X: (), 'a>(_: &'a ()) {
+   |              ^
+
+error: aborting due to 4 previous errors
 

src/test/ui/feature-gates/feature-gate-const_generics.rs

@@ -2,5 +2,6 @@ fn foo<const X: ()>() {} //~ ERROR const generics are unstable
 //~^ const generics in any position are currently unsupported
 
 struct Foo<const X: usize>([(); X]); //~ ERROR const generics are unstable
+//~^ const generics in any position are currently unsupported
 
 fn main() {}

src/test/ui/feature-gates/feature-gate-const_generics.stderr

@@ -20,6 +20,12 @@ error: const generics in any position are currently unsupported
 LL | fn foo<const X: ()>() {} //~ ERROR const generics are unstable
    |              ^
 
-error: aborting due to 3 previous errors
+error: const generics in any position are currently unsupported
+  --> $DIR/feature-gate-const_generics.rs:4:18
+   |
+LL | struct Foo<const X: usize>([(); X]); //~ ERROR const generics are unstable
+   |                  ^
+
+error: aborting due to 4 previous errors
 
 For more information about this error, try `rustc --explain E0658`.