Use the correct crates proc-macro loading error message

crates/hir-def/src/nameres.rs

@@ -103,6 +103,8 @@ pub struct DefMap {
     /// Side table for resolving derive helpers.
     exported_derives: FxHashMap<MacroDefId, Box<[Name]>>,
     fn_proc_macro_mapping: FxHashMap<FunctionId, ProcMacroId>,
+    /// The error that occurred when failing to load the proc-macro dll.
+    proc_macro_loading_error: Option<Box<str>>,
 
     /// Custom attributes registered with `#![register_attr]`.
     registered_attrs: Vec<SmolStr>,
@@ -273,6 +275,7 @@ impl DefMap {
             extern_prelude: FxHashMap::default(),
             exported_derives: FxHashMap::default(),
             fn_proc_macro_mapping: FxHashMap::default(),
+            proc_macro_loading_error: None,
             prelude: None,
             root,
             modules,
@@ -305,6 +308,9 @@ impl DefMap {
     pub fn fn_as_proc_macro(&self, id: FunctionId) -> Option<ProcMacroId> {
         self.fn_proc_macro_mapping.get(&id).copied()
     }
+    pub fn proc_macro_loading_error(&self) -> Option<&str> {
+        self.proc_macro_loading_error.as_deref()
+    }
 
     pub(crate) fn krate(&self) -> CrateId {
         self.krate
@@ -460,6 +466,7 @@ impl DefMap {
             registered_attrs,
             registered_tools,
             fn_proc_macro_mapping,
+            proc_macro_loading_error: _,
             block: _,
             edition: _,
             recursion_limit: _,

crates/hir-def/src/nameres/collector.rs

@@ -74,26 +74,25 @@ pub(super) fn collect_defs(db: &dyn DefDatabase, mut def_map: DefMap, tree_id: T
     }
 
     let cfg_options = &krate.cfg_options;
-    let (proc_macros, proc_macro_err) = match &krate.proc_macro {
+    let proc_macros = match &krate.proc_macro {
         Ok(proc_macros) => {
-            (
             proc_macros
                 .iter()
                 .enumerate()
                 .map(|(idx, it)| {
                     // FIXME: a hacky way to create a Name from string.
-                        let name =
-                            tt::Ident { text: it.name.clone(), id: tt::TokenId::unspecified() };
+                    let name = tt::Ident { text: it.name.clone(), id: tt::TokenId::unspecified() };
                     (
                         name.as_name(),
                         ProcMacroExpander::new(def_map.krate, base_db::ProcMacroId(idx as u32)),
                     )
                 })
-                    .collect(),
-                None,
-            )
+                .collect()
+        }
+        Err(e) => {
+            def_map.proc_macro_loading_error = Some(e.clone().into_boxed_str());
+            Vec::new()
         }
-        Err(e) => (Vec::new(), Some(e.clone())),
     };
     let is_proc_macro = krate.is_proc_macro;
 
@@ -108,7 +107,6 @@ pub(super) fn collect_defs(db: &dyn DefDatabase, mut def_map: DefMap, tree_id: T
         mod_dirs: FxHashMap::default(),
         cfg_options,
         proc_macros,
-        proc_macro_err,
         from_glob_import: Default::default(),
         skip_attrs: Default::default(),
         derive_helpers_in_scope: Default::default(),
@@ -250,7 +248,6 @@ struct DefCollector<'a> {
     /// empty when proc. macro support is disabled (in which case we still do name resolution for
     /// them).
     proc_macros: Vec<(Name, ProcMacroExpander)>,
-    proc_macro_err: Option<String>,
     is_proc_macro: bool,
     from_glob_import: PerNsGlobImports,
     /// If we fail to resolve an attribute on a `ModItem`, we fall back to ignoring the attribute.
@@ -1147,7 +1144,7 @@ impl DefCollector<'_> {
                                     invoc_attr_index: attr.id.ast_index,
                                     is_derive: false,
                                 },
-                                self.proc_macro_err.clone(),
+                                None,
                             ));
                             return true;
                         }
@@ -1254,7 +1251,7 @@ impl DefCollector<'_> {
                             self.def_map.diagnostics.push(DefDiagnostic::unresolved_proc_macro(
                                 directive.module_id,
                                 loc.kind,
-                                self.proc_macro_err.clone(),
+                                Some(loc.def.krate),
                             ));
 
                             return recollect_without(self);
@@ -1309,7 +1306,7 @@ impl DefCollector<'_> {
                     DefDiagnostic::unresolved_proc_macro(
                         module_id,
                         loc.kind.clone(),
-                        self.proc_macro_err.clone(),
+                        Some(loc.def.krate),
                     )
                 }
                 _ => DefDiagnostic::macro_error(module_id, loc.kind.clone(), err.to_string()),
@@ -2124,7 +2121,6 @@ mod tests {
             mod_dirs: FxHashMap::default(),
             cfg_options: &CfgOptions::default(),
             proc_macros: Default::default(),
-            proc_macro_err: None,
             from_glob_import: Default::default(),
             skip_attrs: Default::default(),
             derive_helpers_in_scope: Default::default(),

crates/hir-def/src/nameres/diagnostics.rs

@@ -1,5 +1,6 @@
 //! Diagnostics emitted during DefMap construction.
 
+use base_db::CrateId;
 use cfg::{CfgExpr, CfgOptions};
 use hir_expand::MacroCallKind;
 use la_arena::Idx;
@@ -23,7 +24,7 @@ pub enum DefDiagnosticKind {
 
     UnconfiguredCode { ast: AstId<ast::Item>, cfg: CfgExpr, opts: CfgOptions },
 
-    UnresolvedProcMacro { ast: MacroCallKind, proc_macro_err: Option<String> },
+    UnresolvedProcMacro { ast: MacroCallKind, krate: Option<CrateId> },
 
     UnresolvedMacroCall { ast: MacroCallKind, path: ModPath },
 
@@ -84,12 +85,9 @@ impl DefDiagnostic {
     pub(super) fn unresolved_proc_macro(
         container: LocalModuleId,
         ast: MacroCallKind,
-        proc_macro_err: Option<String>,
+        krate: Option<CrateId>,
     ) -> Self {
-        Self {
-            in_module: container,
-            kind: DefDiagnosticKind::UnresolvedProcMacro { ast, proc_macro_err },
-        }
+        Self { in_module: container, kind: DefDiagnosticKind::UnresolvedProcMacro { ast, krate } }
     }
 
     pub(super) fn macro_error(

crates/hir/src/diagnostics.rs

@@ -3,6 +3,7 @@
 //!
 //! This probably isn't the best way to do this -- ideally, diagnistics should
 //! be expressed in terms of hir types themselves.
+use base_db::CrateId;
 use cfg::{CfgExpr, CfgOptions};
 use either::Either;
 use hir_def::path::ModPath;
@@ -87,7 +88,8 @@ pub struct UnresolvedProcMacro {
     pub precise_location: Option<TextRange>,
     pub macro_name: Option<String>,
     pub kind: MacroKind,
-    pub proc_macro_err: Option<String>,
+    /// The crate id of the proc-macro this macro belongs to, or `None` if the proc-macro can't be found.
+    pub krate: Option<CrateId>,
 }
 
 #[derive(Debug, Clone, Eq, PartialEq)]

crates/hir/src/lib.rs

@@ -627,7 +627,7 @@ fn emit_def_diagnostic(db: &dyn HirDatabase, acc: &mut Vec<AnyDiagnostic>, diag:
             );
         }
 
-        DefDiagnosticKind::UnresolvedProcMacro { ast, proc_macro_err } => {
+        DefDiagnosticKind::UnresolvedProcMacro { ast, krate } => {
             let (node, precise_location, macro_name, kind) = match ast {
                 MacroCallKind::FnLike { ast_id, .. } => {
                     let node = ast_id.to_node(db.upcast());
@@ -690,13 +690,7 @@ fn emit_def_diagnostic(db: &dyn HirDatabase, acc: &mut Vec<AnyDiagnostic>, diag:
                 }
             };
             acc.push(
-                UnresolvedProcMacro {
-                    node,
-                    precise_location,
-                    macro_name,
-                    kind,
-                    proc_macro_err: proc_macro_err.clone(),
-                }
+                UnresolvedProcMacro { node, precise_location, macro_name, kind, krate: *krate }
                     .into(),
             );
         }
@@ -1172,7 +1166,7 @@ impl DefWithBody {
                         precise_location: None,
                         macro_name: None,
                         kind: MacroKind::ProcMacro,
-                        proc_macro_err: None,
+                        krate: None,
                     }
                     .into(),
                 ),

crates/ide-diagnostics/src/handlers/unresolved_proc_macro.rs

@@ -1,3 +1,5 @@
+use hir::db::DefDatabase;
+
 use crate::{Diagnostic, DiagnosticsContext, Severity};
 
 // Diagnostic: unresolved-proc-macro
@@ -30,10 +32,11 @@ pub(crate) fn unresolved_proc_macro(
         None => "proc macro not expanded".to_string(),
     };
     let severity = if config_enabled { Severity::Error } else { Severity::WeakWarning };
+    let def_map = d.krate.map(|krate| ctx.sema.db.crate_def_map(krate));
     let message = format!(
         "{message}: {}",
         if config_enabled {
-            match &d.proc_macro_err {
+            match def_map.as_ref().and_then(|def_map| def_map.proc_macro_loading_error()) {
                 Some(e) => e,
                 None => "proc macro not found",
             }