resolve: derive diag for undetermined macro resolution

Author: bvanjoi

compiler/rustc_resolve/messages.ftl

@@ -58,6 +58,10 @@ resolve_cannot_determine_import_resolution =
     cannot determine resolution for the import
     .note = import resolution is stuck, try simplifying other imports
 
+resolve_cannot_determine_macro_resolution =
+    cannot determine resolution for the {$kind} `{$path}`
+    .note = import resolution is stuck, try simplifying macro imports
+
 resolve_cannot_find_ident_in_this_scope =
     cannot find {$expected} `{$ident}` in this scope
 

compiler/rustc_resolve/src/errors.rs

@@ -654,6 +654,16 @@ pub(crate) struct CannotDetermineImportResolution {
     pub(crate) span: Span,
 }
 
+#[derive(Diagnostic)]
+#[diag(resolve_cannot_determine_macro_resolution)]
+#[note]
+pub(crate) struct CannotDetermineMacroResolution {
+    #[primary_span]
+    pub(crate) span: Span,
+    pub(crate) kind: &'static str,
+    pub(crate) path: String,
+}
+
 #[derive(Diagnostic)]
 #[diag(resolve_cannot_be_reexported_private, code = "E0364")]
 pub(crate) struct CannotBeReexportedPrivate {

compiler/rustc_resolve/src/macros.rs

@@ -2,7 +2,8 @@
 //! interface provided by `Resolver` to macro expander.
 
 use crate::errors::{
-    self, AddAsNonDerive, CannotFindIdentInThisScope, MacroExpectedFound, RemoveSurroundingDerive,
+    self, AddAsNonDerive, CannotDetermineMacroResolution, CannotFindIdentInThisScope,
+    MacroExpectedFound, RemoveSurroundingDerive,
 };
 use crate::Namespace::*;
 use crate::{BuiltinMacroState, Determinacy};
@@ -719,13 +720,11 @@ impl<'a, 'tcx> Resolver<'a, 'tcx> {
                 // even if speculative `resolve_path` returned nothing previously, so we skip this
                 // less informative error if the privacy error is reported elsewhere.
                 if this.privacy_errors.is_empty() {
-                    let msg = format!(
-                        "cannot determine resolution for the {} `{}`",
-                        kind.descr(),
-                        Segment::names_to_string(path)
-                    );
-                    let msg_note = "import resolution is stuck, try simplifying macro imports";
-                    this.tcx.sess.struct_span_err(span, msg).note(msg_note).emit();
+                    this.tcx.sess.emit_err(CannotDetermineMacroResolution {
+                        span,
+                        kind: kind.descr(),
+                        path: Segment::names_to_string(path),
+                    });
                 }
             }
         };