Rollup merge of #89701 - tom7980:issue-89566-fix, r=petrochenkov

Updated error message for accidental uses of derive attribute as a crate attribute

This partially fixes the original issue #89566 by adding derive to the list of invalid crate attributes and then providing an updated error message however I'm not sure how to prevent the resolution error message from emitting without causing the compiler to just abort when it finds an invalid crate attribute (which I'd prefer not to do so we can find and emit other errors).

`@petrochenkov` I have been told you may have some insight on why it's emitting the resolution error though honestly I'm not sure if we need to worry about fixing it as long as we can provide the invalid crate attribute error also (which happens first anyway)

Author: matthiaskrgr

compiler/rustc_passes/src/check_attr.rs

@@ -1953,28 +1953,52 @@ fn is_c_like_enum(item: &Item<'_>) -> bool {
     }
 }
 
+// FIXME: Fix "Cannot determine resolution" error and remove built-in macros
+// from this check.
 fn check_invalid_crate_level_attr(tcx: TyCtxt<'_>, attrs: &[Attribute]) {
+    // Check for builtin attributes at the crate level
+    // which were unsuccessfully resolved due to cannot determine
+    // resolution for the attribute macro error.
     const ATTRS_TO_CHECK: &[Symbol] = &[
         sym::macro_export,
         sym::repr,
         sym::path,
         sym::automatically_derived,
         sym::start,
         sym::rustc_main,
+        sym::derive,
+        sym::test,
+        sym::test_case,
+        sym::global_allocator,
+        sym::bench,
     ];
 
     for attr in attrs {
-        for attr_to_check in ATTRS_TO_CHECK {
-            if attr.has_name(*attr_to_check) {
-                tcx.sess
-                    .struct_span_err(
+        // This function should only be called with crate attributes
+        // which are inner attributes always but lets check to make sure
+        if attr.style == AttrStyle::Inner {
+            for attr_to_check in ATTRS_TO_CHECK {
+                if attr.has_name(*attr_to_check) {
+                    let mut err = tcx.sess.struct_span_err(
                         attr.span,
                         &format!(
                             "`{}` attribute cannot be used at crate level",
                             attr_to_check.to_ident_string()
                         ),
-                    )
-                    .emit();
+                    );
+                    // Only emit an error with a suggestion if we can create a
+                    // string out of the attribute span
+                    if let Ok(src) = tcx.sess.source_map().span_to_snippet(attr.span) {
+                        let replacement = src.replace("#!", "#");
+                        err.span_suggestion_verbose(
+                            attr.span,
+                            "perhaps you meant to use an outer attribute",
+                            replacement,
+                            rustc_errors::Applicability::MachineApplicable,
+                        );
+                    }
+                    err.emit()
+                }
             }
         }
     }

src/test/ui/derives/issue-36617.rs

@@ -1,3 +1,16 @@
 #![derive(Copy)] //~ ERROR cannot determine resolution for the attribute macro `derive`
+//~^ ERROR `derive` attribute cannot be used at crate level
+
+#![test]//~ ERROR cannot determine resolution for the attribute macro `test`
+//~^ ERROR `test` attribute cannot be used at crate level
+
+#![test_case]//~ ERROR cannot determine resolution for the attribute macro `test_case`
+//~^ ERROR `test_case` attribute cannot be used at crate level
+
+#![bench]//~ ERROR cannot determine resolution for the attribute macro `bench`
+//~^ ERROR `bench` attribute cannot be used at crate level
+
+#![global_allocator]//~ ERROR cannot determine resolution for the attribute macro `global_allocator`
+//~^ ERROR `global_allocator` attribute cannot be used at crate level
 
 fn main() {}

src/test/ui/derives/issue-36617.stderr

@@ -6,5 +6,92 @@ LL | #![derive(Copy)]
    |
    = note: import resolution is stuck, try simplifying macro imports
 
-error: aborting due to previous error
+error: cannot determine resolution for the attribute macro `test`
+  --> $DIR/issue-36617.rs:4:4
+   |
+LL | #![test]
+   |    ^^^^
+   |
+   = note: import resolution is stuck, try simplifying macro imports
+
+error: cannot determine resolution for the attribute macro `test_case`
+  --> $DIR/issue-36617.rs:7:4
+   |
+LL | #![test_case]
+   |    ^^^^^^^^^
+   |
+   = note: import resolution is stuck, try simplifying macro imports
+
+error: cannot determine resolution for the attribute macro `bench`
+  --> $DIR/issue-36617.rs:10:4
+   |
+LL | #![bench]
+   |    ^^^^^
+   |
+   = note: import resolution is stuck, try simplifying macro imports
+
+error: cannot determine resolution for the attribute macro `global_allocator`
+  --> $DIR/issue-36617.rs:13:4
+   |
+LL | #![global_allocator]
+   |    ^^^^^^^^^^^^^^^^
+   |
+   = note: import resolution is stuck, try simplifying macro imports
+
+error: `derive` attribute cannot be used at crate level
+  --> $DIR/issue-36617.rs:1:1
+   |
+LL | #![derive(Copy)]
+   | ^^^^^^^^^^^^^^^^
+   |
+help: perhaps you meant to use an outer attribute
+   |
+LL | #[derive(Copy)]
+   | ~~~~~~~~~~~~~~~
+
+error: `test` attribute cannot be used at crate level
+  --> $DIR/issue-36617.rs:4:1
+   |
+LL | #![test]
+   | ^^^^^^^^
+   |
+help: perhaps you meant to use an outer attribute
+   |
+LL | #[test]
+   | ~~~~~~~
+
+error: `test_case` attribute cannot be used at crate level
+  --> $DIR/issue-36617.rs:7:1
+   |
+LL | #![test_case]
+   | ^^^^^^^^^^^^^
+   |
+help: perhaps you meant to use an outer attribute
+   |
+LL | #[test_case]
+   | ~~~~~~~~~~~~
+
+error: `bench` attribute cannot be used at crate level
+  --> $DIR/issue-36617.rs:10:1
+   |
+LL | #![bench]
+   | ^^^^^^^^^
+   |
+help: perhaps you meant to use an outer attribute
+   |
+LL | #[bench]
+   | ~~~~~~~~
+
+error: `global_allocator` attribute cannot be used at crate level
+  --> $DIR/issue-36617.rs:13:1
+   |
+LL | #![global_allocator]
+   | ^^^^^^^^^^^^^^^^^^^^
+   |
+help: perhaps you meant to use an outer attribute
+   |
+LL | #[global_allocator]
+   | ~~~~~~~~~~~~~~~~~~~
+
+error: aborting due to 10 previous errors
 

src/test/ui/feature-gates/issue-43106-gating-of-bench.rs

@@ -6,5 +6,5 @@
 
 #![bench                   = "4100"]
 //~^ ERROR cannot determine resolution for the attribute macro `bench`
-
+//~^^ ERROR `bench` attribute cannot be used at crate level
 fn main() {}

src/test/ui/feature-gates/issue-43106-gating-of-bench.stderr

@@ -6,5 +6,16 @@ LL | #![bench                   = "4100"]
    |
    = note: import resolution is stuck, try simplifying macro imports
 
-error: aborting due to previous error
+error: `bench` attribute cannot be used at crate level
+  --> $DIR/issue-43106-gating-of-bench.rs:7:1
+   |
+LL | #![bench                   = "4100"]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+help: perhaps you meant to use an outer attribute
+   |
+LL | #[bench                   = "4100"]
+   |
+
+error: aborting due to 2 previous errors
 

src/test/ui/feature-gates/issue-43106-gating-of-builtin-attrs-error.stderr

@@ -129,36 +129,66 @@ error: `macro_export` attribute cannot be used at crate level
    |
 LL | #![macro_export]
    | ^^^^^^^^^^^^^^^^
+   |
+help: perhaps you meant to use an outer attribute
+   |
+LL | #[macro_export]
+   |
 
 error: `rustc_main` attribute cannot be used at crate level
   --> $DIR/issue-43106-gating-of-builtin-attrs-error.rs:14:1
    |
 LL | #![rustc_main]
    | ^^^^^^^^^^^^^^
+   |
+help: perhaps you meant to use an outer attribute
+   |
+LL | #[rustc_main]
+   | ~~~~~~~~~~~~~
 
 error: `start` attribute cannot be used at crate level
   --> $DIR/issue-43106-gating-of-builtin-attrs-error.rs:16:1
    |
 LL | #![start]
    | ^^^^^^^^^
+   |
+help: perhaps you meant to use an outer attribute
+   |
+LL | #[start]
+   |
 
 error: `repr` attribute cannot be used at crate level
   --> $DIR/issue-43106-gating-of-builtin-attrs-error.rs:18:1
    |
 LL | #![repr()]
    | ^^^^^^^^^^
+   |
+help: perhaps you meant to use an outer attribute
+   |
+LL | #[repr()]
+   |
 
 error: `path` attribute cannot be used at crate level
   --> $DIR/issue-43106-gating-of-builtin-attrs-error.rs:20:1
    |
 LL | #![path = "3800"]
    | ^^^^^^^^^^^^^^^^^
+   |
+help: perhaps you meant to use an outer attribute
+   |
+LL | #[path = "3800"]
+   |
 
 error: `automatically_derived` attribute cannot be used at crate level
   --> $DIR/issue-43106-gating-of-builtin-attrs-error.rs:22:1
    |
 LL | #![automatically_derived]
    | ^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+help: perhaps you meant to use an outer attribute
+   |
+LL | #[automatically_derived]
+   |
 
 error[E0518]: attribute should be applied to function or closure
   --> $DIR/issue-43106-gating-of-builtin-attrs-error.rs:36:17

src/test/ui/feature-gates/issue-43106-gating-of-test.rs

@@ -3,5 +3,5 @@
 #![allow(soft_unstable)]
 #![test                    = "4200"]
 //~^ ERROR cannot determine resolution for the attribute macro `test`
-
+//~^^ ERROR `test` attribute cannot be used at crate level
 fn main() {}

src/test/ui/feature-gates/issue-43106-gating-of-test.stderr

@@ -6,5 +6,16 @@ LL | #![test                    = "4200"]
    |
    = note: import resolution is stuck, try simplifying macro imports
 
-error: aborting due to previous error
+error: `test` attribute cannot be used at crate level
+  --> $DIR/issue-43106-gating-of-test.rs:4:1
+   |
+LL | #![test                    = "4200"]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+help: perhaps you meant to use an outer attribute
+   |
+LL | #[test                    = "4200"]
+   |
+
+error: aborting due to 2 previous errors
 

src/test/ui/imports/issue-28134.rs

@@ -2,3 +2,4 @@
 
 #![allow(soft_unstable)]
 #![test] //~ ERROR cannot determine resolution for the attribute macro `test`
+//~^ ERROR 4:1: 4:9: `test` attribute cannot be used at crate level

src/test/ui/imports/issue-28134.stderr

@@ -6,5 +6,16 @@ LL | #![test]
    |
    = note: import resolution is stuck, try simplifying macro imports
 
-error: aborting due to previous error
+error: `test` attribute cannot be used at crate level
+  --> $DIR/issue-28134.rs:4:1
+   |
+LL | #![test]
+   | ^^^^^^^^
+   |
+help: perhaps you meant to use an outer attribute
+   |
+LL | #[test]
+   | ~~~~~~~
+
+error: aborting due to 2 previous errors
 

src/test/ui/span/issue-43927-non-ADT-derive.rs

@@ -1,5 +1,6 @@
 #![derive(Debug, PartialEq, Eq)] // should be an outer attribute!
 //~^ ERROR cannot determine resolution for the attribute macro `derive`
+//~^^ ERROR `derive` attribute cannot be used at crate level
 struct DerivedOn;
 
 fn main() {}

src/test/ui/span/issue-43927-non-ADT-derive.stderr

@@ -6,5 +6,16 @@ LL | #![derive(Debug, PartialEq, Eq)] // should be an outer attribute!
    |
    = note: import resolution is stuck, try simplifying macro imports
 
-error: aborting due to previous error
+error: `derive` attribute cannot be used at crate level
+  --> $DIR/issue-43927-non-ADT-derive.rs:1:1
+   |
+LL | #![derive(Debug, PartialEq, Eq)] // should be an outer attribute!
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+help: perhaps you meant to use an outer attribute
+   |
+LL | #[derive(Debug, PartialEq, Eq)] // should be an outer attribute!
+   | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+error: aborting due to 2 previous errors