Fix span for IndexMut method call on HashMap/BTreeMap

Author: compiler-errors

compiler/rustc_borrowck/src/diagnostics/mutability_errors.rs

@@ -624,7 +624,7 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
                         self.suggested = true;
                     } else if let hir::ExprKind::MethodCall(_path, receiver, _, sp) = expr.kind
                         && let hir::ExprKind::Index(val, index, _) = receiver.kind
-                        && expr.span == self.assign_span
+                        && receiver.span == self.assign_span
                     {
                         // val[index].path(args..);
                         self.err.multipart_suggestion(
@@ -639,7 +639,7 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
                                     index.span.shrink_to_hi().with_hi(receiver.span.hi()),
                                     ") { val".to_string(),
                                 ),
-                                (sp.shrink_to_hi(), "); }".to_string()),
+                                (sp.shrink_to_hi(), "; }".to_string()),
                             ],
                             Applicability::MachineApplicable,
                         );

tests/ui/borrowck/index-mut-help.stderr

@@ -5,7 +5,10 @@ LL |     map["peter"].clear();
    |     ^^^^^^^^^^^^ cannot borrow as mutable
    |
    = help: trait `IndexMut` is required to modify indexed content, but it is not implemented for `HashMap<&str, String>`
-   = help: to modify a `HashMap<&str, String>`, use `.get_mut()`, `.insert()` or the entry API
+help: to modify a `HashMap<&str, String>` use `.get_mut()`
+   |
+LL |     if let Some(val) = map.get_mut("peter") { val.clear(); };
+   |     ++++++++++++++++++    ~~~~~~~~~       ~~~~~~~        +++
 
 error[E0594]: cannot assign to data in an index of `HashMap<&str, String>`
   --> $DIR/index-mut-help.rs:11:5

tests/ui/issues/issue-41726.stderr

@@ -5,7 +5,10 @@ LL |         things[src.as_str()].sort();
    |         ^^^^^^^^^^^^^^^^^^^^ cannot borrow as mutable
    |
    = help: trait `IndexMut` is required to modify indexed content, but it is not implemented for `HashMap<String, Vec<String>>`
-   = help: to modify a `HashMap<String, Vec<String>>`, use `.get_mut()`, `.insert()` or the entry API
+help: to modify a `HashMap<String, Vec<String>>` use `.get_mut()`
+   |
+LL |         if let Some(val) = things.get_mut(src.as_str()) { val.sort(); };
+   |         ++++++++++++++++++       ~~~~~~~~~            ~~~~~~~       +++
 
 error: aborting due to 1 previous error