Merge #1815

1815: Support correct `$crate` expansion in macros r=uHOOCCOOHu a=uHOOCCOOHu

This PR makes normal use cases of `$crate` from macros work as expected.

It makes more macros from `std` work. Type inference works well with `panic`, `unimplemented`, `format`, and maybe more.
Sadly that `vec![1, 2, 3]` still not works, but it is not longer an issue about macro.

Screenshot:
![Screenshot_20190927_022136](https://user-images.githubusercontent.com/14816024/65714465-b4568f80-e0cd-11e9-8043-dd44c2ae8040.png)




Co-authored-by: uHOOCCOOHu <[email protected]>

1 files changed, 4 insertions, 1 deletions

diff --git a/crates/ra_hir/src/impl_block.rs b/crates/ra_hir/src/impl_block.rs
index d830202bd..c66a1c6a6 100644
--- a/crates/ra_hir/src/impl_block.rs
+++ b/crates/ra_hir/src/impl_block.rs
@@ -218,7 +218,10 @@ impl ModuleImplBlocks {
                 ast::ItemOrMacro::Macro(macro_call) => {
                     //FIXME: we should really cut down on the boilerplate required to process a macro
                     let ast_id = db.ast_id_map(file_id).ast_id(&macro_call).with_file_id(file_id);
-                    if let Some(path) = macro_call.path().and_then(Path::from_ast) {
+                    if let Some(path) = macro_call
+                        .path()
+                        .and_then(|path| Path::from_src(Source { ast: path, file_id }, db))
+                    {
                         if let Some(def) = self.module.resolver(db).resolve_path_as_macro(db, &path)
                         {
                             let call_id = MacroCallLoc { def: def.id, ast_id }.id(db);