Fix explicit-outlives-requirements lint span

Author: sginnett

compiler/rustc_lint/src/builtin.rs

@@ -2124,12 +2124,16 @@ impl<'tcx> LateLintPass<'tcx> for ExplicitOutlivesRequirements {
             }
 
             let ty_generics = cx.tcx.generics_of(def_id);
+            let num_where_predicates = hir_generics
+                .predicates
+                .iter()
+                .filter(|predicate| predicate.in_where_clause())
+                .count();
 
             let mut bound_count = 0;
             let mut lint_spans = Vec::new();
             let mut where_lint_spans = Vec::new();
-            let mut dropped_predicate_count = 0;
-            let num_predicates = hir_generics.predicates.len();
+            let mut dropped_where_predicate_count = 0;
             for (i, where_predicate) in hir_generics.predicates.iter().enumerate() {
                 let (relevant_lifetimes, bounds, predicate_span, in_where_clause) =
                     match where_predicate {
@@ -2186,8 +2190,8 @@ impl<'tcx> LateLintPass<'tcx> for ExplicitOutlivesRequirements {
                 bound_count += bound_spans.len();
 
                 let drop_predicate = bound_spans.len() == bounds.len();
-                if drop_predicate {
-                    dropped_predicate_count += 1;
+                if drop_predicate && in_where_clause {
+                    dropped_where_predicate_count += 1;
                 }
 
                 if drop_predicate {
@@ -2196,7 +2200,7 @@ impl<'tcx> LateLintPass<'tcx> for ExplicitOutlivesRequirements {
                     } else if predicate_span.from_expansion() {
                         // Don't try to extend the span if it comes from a macro expansion.
                         where_lint_spans.push(predicate_span);
-                    } else if i + 1 < num_predicates {
+                    } else if i + 1 < num_where_predicates {
                         // If all the bounds on a predicate were inferable and there are
                         // further predicates, we want to eat the trailing comma.
                         let next_predicate_span = hir_generics.predicates[i + 1].span();
@@ -2224,9 +2228,10 @@ impl<'tcx> LateLintPass<'tcx> for ExplicitOutlivesRequirements {
                 }
             }
 
-            // If all predicates are inferable, drop the entire clause
+            // If all predicates in where clause are inferable, drop the entire clause
             // (including the `where`)
-            if hir_generics.has_where_clause_predicates && dropped_predicate_count == num_predicates
+            if hir_generics.has_where_clause_predicates
+                && dropped_where_predicate_count == num_where_predicates
             {
                 let where_span = hir_generics.where_clause_span;
                 // Extend the where clause back to the closing `>` of the

tests/ui/rust-2018/edition-lint-infer-outlives.fixed

@@ -801,4 +801,10 @@ where
     yoo: &'a U
 }
 
+// https://github.com/rust-lang/rust/issues/105150
+struct InferredWhereBoundWithInlineBound<'a, T: ?Sized>
+{
+    data: &'a T,
+}
+
 fn main() {}

tests/ui/rust-2018/edition-lint-infer-outlives.rs

@@ -801,4 +801,12 @@ where
     yoo: &'a U
 }
 
+// https://github.com/rust-lang/rust/issues/105150
+struct InferredWhereBoundWithInlineBound<'a, T: ?Sized>
+//~^ ERROR outlives requirements can be inferred
+    where T: 'a,
+{
+    data: &'a T,
+}
+
 fn main() {}

tests/ui/rust-2018/edition-lint-infer-outlives.stderr

@@ -10,6 +10,15 @@ note: the lint level is defined here
 LL | #![deny(explicit_outlives_requirements)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
+error: outlives requirements can be inferred
+  --> $DIR/edition-lint-infer-outlives.rs:805:56
+   |
+LL |   struct InferredWhereBoundWithInlineBound<'a, T: ?Sized>
+   |  ________________________________________________________^
+LL | |
+LL | |     where T: 'a,
+   | |________________^ help: remove this bound
+
 error: outlives requirements can be inferred
   --> $DIR/edition-lint-infer-outlives.rs:26:31
    |
@@ -922,5 +931,5 @@ error: outlives requirements can be inferred
 LL |     union BeeWhereOutlivesAyTeeWhereDebug<'a, 'b, T> where 'b: 'a, T: Debug {
    |                                                            ^^^^^^^^ help: remove this bound
 
-error: aborting due to 153 previous errors
+error: aborting due to 154 previous errors