Fix duplicate warning; merge test into tests/ui-fulldeps/internal-lints

Author: smoelius

compiler/rustc_lint/src/internal.rs

@@ -133,6 +133,9 @@ fn check_into_iter_stability<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx
     let Some(into_iterator_def_id) = cx.tcx.get_diagnostic_item(sym::IntoIterator) else {
         return;
     };
+    if expr.span.from_expansion() {
+        return;
+    };
     // Is `expr` a function or method call?
     let Some((callee_def_id, generic_args, recv, args)) =
         get_callee_generic_args_and_args(cx, expr)

tests/ui-fulldeps/internal-lints/query_stability.rs

@@ -34,4 +34,7 @@ fn main() {
         //~^ ERROR using `values_mut` can result in unstable query results
         *val = *val + 10;
     }
+
+    FxHashMap::<u32, i32>::default().extend(x);
+    //~^ ERROR using `into_iter` can result in unstable query results
 }

tests/ui-fulldeps/internal-lints/query_stability.stderr

@@ -59,5 +59,13 @@ LL |     for val in x.values_mut() {
    |
    = note: if you believe this case to be fine, allow this lint and add a comment explaining your rationale
 
-error: aborting due to 7 previous errors
+error: using `into_iter` can result in unstable query results
+  --> $DIR/query_stability.rs:38:45
+   |
+LL |     FxHashMap::<u32, i32>::default().extend(x);
+   |                                             ^
+   |
+   = note: if you believe this case to be fine, allow this lint and add a comment explaining your rationale
+
+error: aborting due to 8 previous errors