Show what things are, but also what they are not.

Author: m-ou-se

compiler/rustc_resolve/src/diagnostics.rs

@@ -978,7 +978,13 @@ impl<'a> Resolver<'a> {
                     Some(MacroKind::Derive) => format!("a derive macro: `#[derive({})]`", ident),
                     // Don't confuse the user with tool modules.
                     None if res == Res::ToolMod => continue,
-                    None => format!("{} {}", res.article(), res.descr()),
+                    None => format!(
+                        "{} {}, not {} {}",
+                        res.article(),
+                        res.descr(),
+                        macro_kind.article(),
+                        macro_kind.descr_expected(),
+                    ),
                 };
                 if let crate::NameBindingKind::Import { import, .. } = binding.kind {
                     if !import.span.is_dummy() {

src/test/ui/macros/issue-88206.stderr

@@ -4,7 +4,7 @@ error: cannot find macro `X` in this scope
 LL |     X!();
    |     ^
    |
-note: `X` is imported here, but it is a struct
+note: `X` is imported here, but it is a struct, not a macro
   --> $DIR/issue-88206.rs:17:35
    |
 LL | use hey::{Serialize, Deserialize, X};
@@ -32,15 +32,15 @@ error: cannot find macro `Box` in this scope
 LL |     Box!();
    |     ^^^
    |
-   = note: `Box` is in scope, but it is a struct
+   = note: `Box` is in scope, but it is a struct, not a macro
 
 error: cannot find macro `from_utf8` in this scope
   --> $DIR/issue-88206.rs:49:5
    |
 LL |     from_utf8!();
    |     ^^^^^^^^^
    |
-note: `from_utf8` is imported here, but it is a function
+note: `from_utf8` is imported here, but it is a function, not a macro
   --> $DIR/issue-88206.rs:5:5
    |
 LL | use std::str::*;
@@ -60,7 +60,7 @@ error: cannot find attribute `from_utf8_unchecked` in this scope
 LL | #[from_utf8_unchecked]
    |   ^^^^^^^^^^^^^^^^^^^
    |
-note: `from_utf8_unchecked` is imported here, but it is a function
+note: `from_utf8_unchecked` is imported here, but it is a function, not an attribute
   --> $DIR/issue-88206.rs:5:5
    |
 LL | use std::str::*;
@@ -72,7 +72,7 @@ error: cannot find attribute `Deserialize` in this scope
 LL | #[Deserialize]
    |   ^^^^^^^^^^^
    |
-note: `Deserialize` is imported here, but it is a trait
+note: `Deserialize` is imported here, but it is a trait, not an attribute
   --> $DIR/issue-88206.rs:17:22
    |
 LL | use hey::{Serialize, Deserialize, X};
@@ -92,7 +92,7 @@ error: cannot find derive macro `from_utf8_mut` in this scope
 LL | #[derive(from_utf8_mut)]
    |          ^^^^^^^^^^^^^
    |
-note: `from_utf8_mut` is imported here, but it is a function
+note: `from_utf8_mut` is imported here, but it is a function, not a derive macro
   --> $DIR/issue-88206.rs:5:5
    |
 LL | use std::str::*;
@@ -104,7 +104,7 @@ error: cannot find derive macro `Serialize` in this scope
 LL | #[derive(Serialize)]
    |          ^^^^^^^^^
    |
-note: `Serialize` is imported here, but it is a trait
+note: `Serialize` is imported here, but it is a trait, not a derive macro
   --> $DIR/issue-88206.rs:17:11
    |
 LL | use hey::{Serialize, Deserialize, X};