Properly set the working directory for proc-macro execution

crates/hir-def/src/macro_expansion_tests/mod.rs

@@ -320,6 +320,7 @@ impl ProcMacroExpander for IdentityWhenValidProcMacroExpander {
         _: Span,
         _: Span,
         _: Span,
+        _: Option<String>,
     ) -> Result<Subtree, ProcMacroExpansionError> {
         let (parse, _) = syntax_bridge::token_tree_to_syntax_node(
             subtree,

crates/hir-expand/src/proc_macro.rs

@@ -29,6 +29,7 @@ pub trait ProcMacroExpander: fmt::Debug + Send + Sync + RefUnwindSafe {
         def_site: Span,
         call_site: Span,
         mixed_site: Span,
+        current_dir: Option<String>,
     ) -> Result<tt::Subtree, ProcMacroExpansionError>;
 }
 
@@ -234,8 +235,18 @@ impl CustomProcMacroExpander {
                 let krate_graph = db.crate_graph();
                 // Proc macros have access to the environment variables of the invoking crate.
                 let env = &krate_graph[calling_crate].env;
-                match proc_macro.expander.expand(tt, attr_arg, env, def_site, call_site, mixed_site)
+                match proc_macro.expander.expand(
-                {
+                    tt,
+                    attr_arg,
+                    env,
+                    def_site,
+                    call_site,
+                    mixed_site,
+                    db.crate_workspace_data()[&calling_crate]
+                        .proc_macro_cwd
+                        .as_ref()
+                        .map(ToString::to_string),
+                ) {
                     Ok(t) => ExpandResult::ok(t),
                     Err(err) => match err {
                         // Don't discard the item in case something unexpected happened while expanding attributes

crates/load-cargo/src/lib.rs

@@ -493,8 +493,17 @@ impl ProcMacroExpander for Expander {
         def_site: Span,
         call_site: Span,
         mixed_site: Span,
+        current_dir: Option<String>,
     ) -> Result<tt::Subtree<Span>, ProcMacroExpansionError> {
-        match self.0.expand(subtree, attrs, env.clone(), def_site, call_site, mixed_site) {
+        match self.0.expand(
+            subtree,
+            attrs,
+            env.clone(),
+            def_site,
+            call_site,
+            mixed_site,
+            current_dir,
+        ) {
             Ok(Ok(subtree)) => Ok(subtree),
             Ok(Err(err)) => Err(ProcMacroExpansionError::Panic(err.0)),
             Err(err) => Err(ProcMacroExpansionError::System(err.to_string())),

crates/proc-macro-api/src/lib.rs

@@ -152,10 +152,9 @@ impl ProcMacro {
         def_site: Span,
         call_site: Span,
         mixed_site: Span,
+        current_dir: Option<String>,
     ) -> Result<Result<tt::Subtree<Span>, PanicMessage>, ServerError> {
         let version = self.process.version();
-        let current_dir =
-            env.get("CARGO_RUSTC_CURRENT_DIR").or_else(|| env.get("CARGO_MANIFEST_DIR"));
 
         let mut span_data_table = SpanDataIndexMap::default();
         let def_site = span_data_table.insert_full(def_site).0;

crates/test-fixture/src/lib.rs

@@ -571,6 +571,7 @@ impl ProcMacroExpander for IdentityProcMacroExpander {
         _: Span,
         _: Span,
         _: Span,
+        _: Option<String>,
     ) -> Result<Subtree<Span>, ProcMacroExpansionError> {
         Ok(subtree.clone())
     }
@@ -588,6 +589,7 @@ impl ProcMacroExpander for AttributeInputReplaceProcMacroExpander {
         _: Span,
         _: Span,
         _: Span,
+        _: Option<String>,
     ) -> Result<Subtree<Span>, ProcMacroExpansionError> {
         attrs
             .cloned()
@@ -606,6 +608,7 @@ impl ProcMacroExpander for MirrorProcMacroExpander {
         _: Span,
         _: Span,
         _: Span,
+        _: Option<String>,
     ) -> Result<Subtree<Span>, ProcMacroExpansionError> {
         fn traverse(input: &Subtree<Span>) -> Subtree<Span> {
             let mut token_trees = vec![];
@@ -636,6 +639,7 @@ impl ProcMacroExpander for ShortenProcMacroExpander {
         _: Span,
         _: Span,
         _: Span,
+        _: Option<String>,
     ) -> Result<Subtree<Span>, ProcMacroExpansionError> {
         return Ok(traverse(input));