Merge #8916

8916: ItemTree pretty-printing r=jonas-schievink a=jonas-schievink

This adds a printer for `ItemTree` contents, and a few tests to ensure that `ItemTree` lowering works like we expect it to. It also adds a new "Debug ItemTree" command that can be used to see the `ItemTree` of the currently open file. The pretty-printed output is usually close enough to Rust syntax that we can even use Rust syntax highlighting.

This is similar to the old `ItemTree` tests we had, but produces significantly more readable output, so these should actually carry their weight.

Co-authored-by: Jonas Schievink <[email protected]>

1 files changed, 9 insertions, 0 deletions

diff --git a/crates/hir_def/src/path.rs b/crates/hir_def/src/path.rs
index a43441b1c..9b8873fd2 100644
--- a/crates/hir_def/src/path.rs
+++ b/crates/hir_def/src/path.rs
@@ -46,6 +46,15 @@ pub enum ImportAlias {
     Alias(Name),
 }
 
+impl Display for ImportAlias {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            ImportAlias::Underscore => f.write_str("_"),
+            ImportAlias::Alias(name) => f.write_str(&name.to_string()),
+        }
+    }
+}
+
 impl ModPath {
     pub fn from_src(db: &dyn DefDatabase, path: ast::Path, hygiene: &Hygiene) -> Option<ModPath> {
         let ctx = LowerCtx::with_hygiene(db, hygiene);