diff options
| -rw-r--r-- | src/librustc/hir/lowering.rs | 24 |
1 files changed, 23 insertions, 1 deletions
diff --git a/src/librustc/hir/lowering.rs b/src/librustc/hir/lowering.rs index e53deaf8788..b3ba2968c9f 100644 --- a/src/librustc/hir/lowering.rs +++ b/src/librustc/hir/lowering.rs @@ -3070,7 +3070,29 @@ impl<'a> LoweringContext<'a> { hir::ItemKind::Use(path, hir::UseKind::Glob) } UseTreeKind::Nested(ref trees) => { - // Nested imports are desugared into simple imports. + // Nested imports are desugared into simple + // imports. So if we start with + // + // ``` + // pub(x) use foo::{a, b}; + // ``` + // + // we will create three items: + // + // ``` + // pub(x) use foo::a; + // pub(x) use foo::b; + // pub(x) use foo::{}; // <-- this is called the `ListStem` + // ``` + // + // The first two are produced by recursively invoking + // `lower_use_tree` (and indeed there may be things + // like `use foo::{a::{b, c}}` and so forth). They + // wind up being directly added to + // `self.items`. However, the structure of this + // function also requires us to return one item, and + // for that we return the `{}` import (called the + // "`ListStem`"). let prefix = Path { segments, |