Supress unhelpful diagnostics for unresolved top level attributes

Author: chenyukang

compiler/rustc_attr/messages.ftl

@@ -34,6 +34,12 @@ attr_incorrect_repr_format_generic =
 attr_incorrect_repr_format_packed_one_or_zero_arg =
     incorrect `repr(packed)` attribute format: `packed` takes exactly one parenthesized argument, or no parentheses at all
 
+attr_invalid_attr_at_crate_level =
+    `{$name}` attribute cannot be used at crate level
+    .suggestion = perhaps you meant to use an outer attribute
+
+attr_invalid_attr_at_crate_level_item =
+    the inner attribute doesn't annotate this {$kind}
 attr_invalid_issue_string =
     `issue` must be a non-zero numeric string or "none"
     .must_not_be_zero = `issue` must not be "0", use "none" instead

compiler/rustc_attr/src/lib.rs

@@ -25,5 +25,6 @@ pub use StabilityLevel::*;
 pub use rustc_ast::attr::*;
 
 pub(crate) use rustc_session::HashStableContext;
+pub use session_diagnostics::{InvalidAttrAtCrateLevel, ItemFollowingInnerAttr};
 
 rustc_fluent_macro::fluent_messages! { "../messages.ftl" }

compiler/rustc_attr/src/session_diagnostics.rs

@@ -391,3 +391,40 @@ pub(crate) struct UnknownVersionLiteral {
     #[primary_span]
     pub span: Span,
 }
+
+pub struct InvalidAttrAtCrateLevel {
+    pub span: Span,
+    pub sugg_span: Option<Span>,
+    pub name: Symbol,
+    pub item: Option<ItemFollowingInnerAttr>,
+}
+
+#[derive(Clone, Copy)]
+pub struct ItemFollowingInnerAttr {
+    pub span: Span,
+    pub kind: &'static str,
+}
+
+impl<G: EmissionGuarantee> IntoDiagnostic<'_, G> for InvalidAttrAtCrateLevel {
+    #[track_caller]
+    fn into_diagnostic(self, dcx: &'_ DiagCtxt, level: Level) -> DiagnosticBuilder<'_, G> {
+        let mut diag = DiagnosticBuilder::new(dcx, level, fluent::attr_invalid_attr_at_crate_level);
+        diag.set_span(self.span);
+        diag.set_arg("name", self.name);
+        // Only emit an error with a suggestion if we can create a string out
+        // of the attribute span
+        if let Some(span) = self.sugg_span {
+            diag.span_suggestion_verbose(
+                span,
+                fluent::attr_suggestion,
+                String::new(),
+                Applicability::MachineApplicable,
+            );
+        }
+        if let Some(item) = self.item {
+            diag.set_arg("kind", item.kind);
+            diag.span_label(item.span, fluent::attr_invalid_attr_at_crate_level_item);
+        }
+        diag
+    }
+}

compiler/rustc_passes/messages.ftl

@@ -389,13 +389,6 @@ passes_inline_not_fn_or_closure =
 passes_inner_crate_level_attr =
     crate-level attribute should be in the root module
 
-passes_invalid_attr_at_crate_level =
-    `{$name}` attribute cannot be used at crate level
-    .suggestion = perhaps you meant to use an outer attribute
-
-passes_invalid_attr_at_crate_level_item =
-    the inner attribute doesn't annotate this {$kind}
-
 passes_invalid_macro_export_arguments = `{$name}` isn't a valid `#[macro_export]` argument
 
 passes_invalid_macro_export_arguments_too_many_items = `#[macro_export]` can only take 1 or 0 arguments

compiler/rustc_passes/src/check_attr.rs

@@ -2503,12 +2503,8 @@ fn is_c_like_enum(item: &Item<'_>) -> bool {
     }
 }
 
-// FIXME: Fix "Cannot determine resolution" error and remove built-in macros
-// from this check.
+// Built-in macros will be checked in resolve.
 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,
@@ -2517,11 +2513,6 @@ fn check_invalid_crate_level_attr(tcx: TyCtxt<'_>, attrs: &[Attribute]) {
         sym::start,
         sym::rustc_main,
         sym::unix_sigpipe,
-        sym::derive,
-        sym::test,
-        sym::test_case,
-        sym::global_allocator,
-        sym::bench,
     ];
 
     for attr in attrs {
@@ -2535,11 +2526,11 @@ fn check_invalid_crate_level_attr(tcx: TyCtxt<'_>, attrs: &[Attribute]) {
                         .items()
                         .map(|id| tcx.hir().item(id))
                         .find(|item| !item.span.is_dummy()) // Skip prelude `use`s
-                        .map(|item| errors::ItemFollowingInnerAttr {
+                        .map(|item| rustc_attr::ItemFollowingInnerAttr {
                             span: item.ident.span,
                             kind: item.kind.descr(),
                         });
-                    tcx.dcx().emit_err(errors::InvalidAttrAtCrateLevel {
+                    tcx.dcx().emit_err(rustc_attr::InvalidAttrAtCrateLevel {
                         span: attr.span,
                         sugg_span: tcx
                             .sess

compiler/rustc_passes/src/errors.rs

@@ -850,44 +850,6 @@ pub struct UnknownLangItem {
     pub name: Symbol,
 }
 
-pub struct InvalidAttrAtCrateLevel {
-    pub span: Span,
-    pub sugg_span: Option<Span>,
-    pub name: Symbol,
-    pub item: Option<ItemFollowingInnerAttr>,
-}
-
-#[derive(Clone, Copy)]
-pub struct ItemFollowingInnerAttr {
-    pub span: Span,
-    pub kind: &'static str,
-}
-
-impl<G: EmissionGuarantee> IntoDiagnostic<'_, G> for InvalidAttrAtCrateLevel {
-    #[track_caller]
-    fn into_diagnostic(self, dcx: &'_ DiagCtxt, level: Level) -> DiagnosticBuilder<'_, G> {
-        let mut diag =
-            DiagnosticBuilder::new(dcx, level, fluent::passes_invalid_attr_at_crate_level);
-        diag.set_span(self.span);
-        diag.set_arg("name", self.name);
-        // Only emit an error with a suggestion if we can create a string out
-        // of the attribute span
-        if let Some(span) = self.sugg_span {
-            diag.span_suggestion_verbose(
-                span,
-                fluent::passes_suggestion,
-                String::new(),
-                Applicability::MachineApplicable,
-            );
-        }
-        if let Some(item) = self.item {
-            diag.set_arg("kind", item.kind);
-            diag.span_label(item.span, fluent::passes_invalid_attr_at_crate_level_item);
-        }
-        diag
-    }
-}
-
 #[derive(Diagnostic)]
 #[diag(passes_duplicate_diagnostic_item_in_crate)]
 pub struct DuplicateDiagnosticItemInCrate {

compiler/rustc_resolve/src/errors.rs

@@ -778,3 +778,16 @@ pub(crate) struct IsNotDirectlyImportable {
     pub(crate) span: Span,
     pub(crate) target: Ident,
 }
+
+#[derive(Subdiagnostic)]
+#[suggestion(
+    resolve_suggestion,
+    code = "",
+    applicability = "machine-applicable",
+    style = "verbose"
+)]
+pub(crate) struct InvalidAttrSugg {
+    #[primary_span]
+    pub(crate) span: Span,
+    pub(crate) name: Symbol,
+}

compiler/rustc_resolve/src/macros.rs

@@ -10,7 +10,9 @@ use crate::{BuiltinMacroState, Determinacy, MacroData};
 use crate::{DeriveData, Finalize, ParentScope, ResolutionError, Resolver, ScopeSet};
 use crate::{ModuleKind, ModuleOrUniformRoot, NameBinding, PathResult, Segment, ToNameBinding};
 use rustc_ast::expand::StrippedCfgItem;
-use rustc_ast::{self as ast, attr, Crate, Inline, ItemKind, ModKind, NodeId};
+use rustc_ast::{
+    self as ast, attr, AttrStyle, Attribute, Crate, Inline, ItemKind, ModKind, NodeId,
+};
 use rustc_ast_pretty::pprust;
 use rustc_attr::StabilityLevel;
 use rustc_data_structures::intern::Interned;
@@ -35,7 +37,7 @@ use rustc_span::edition::Edition;
 use rustc_span::hygiene::{self, ExpnData, ExpnKind, LocalExpnId};
 use rustc_span::hygiene::{AstPass, MacroKind};
 use rustc_span::symbol::{kw, sym, Ident, Symbol};
-use rustc_span::{Span, DUMMY_SP};
+use rustc_span::{BytePos, Span, DUMMY_SP};
 use std::cell::Cell;
 use std::mem;
 
@@ -695,6 +697,32 @@ impl<'a, 'tcx> Resolver<'a, 'tcx> {
         res.map(|res| (self.get_macro(res).map(|macro_data| macro_data.ext.clone()), res))
     }
 
+    fn report_invalid_crate_level_attr(&mut self, attrs: &[Attribute], name: Symbol) -> bool {
+        for attr in attrs.iter().filter(|attr| attr.style == AttrStyle::Inner) {
+            if attr.has_name(name) {
+                let tcx = self.tcx;
+                tcx.dcx().emit_err(rustc_attr::InvalidAttrAtCrateLevel {
+                    span: attr.span,
+                    sugg_span: tcx
+                        .sess
+                        .source_map()
+                        .span_to_snippet(attr.span)
+                        .ok()
+                        .filter(|src| src.starts_with("#!["))
+                        .map(|_| {
+                            attr.span
+                                .with_lo(attr.span.lo() + BytePos(1))
+                                .with_hi(attr.span.lo() + BytePos(2))
+                        }),
+                    name,
+                    item: None,
+                });
+                return true;
+            }
+        }
+        false
+    }
+
     pub(crate) fn finalize_macro_resolutions(&mut self, krate: &Crate) {
         let check_consistency = |this: &mut Self,
                                  path: &[Segment],
@@ -714,15 +742,29 @@ impl<'a, 'tcx> Resolver<'a, 'tcx> {
                 // expanded into a dummy fragment for recovery during expansion.
                 // Now, post-expansion, the resolution may succeed, but we can't change the
                 // past and need to report an error.
-                // However, non-speculative `resolve_path` can successfully return private items
+                // Special cases:
+                // 1. non-speculative `resolve_path` can successfully return private items
                 // even if speculative `resolve_path` returned nothing previously, so we skip this
                 // less informative error if the privacy error is reported elsewhere.
+                // 2. issue #118455, unresolved top level attribute error didn't imported prelude and
+                // already have emitted an error, report builtin macro and attributes error by the way,
+                // so `check_invalid_crate_level_attr` in can ignore them.
+
                 if this.privacy_errors.is_empty() {
-                    this.dcx().emit_err(CannotDetermineMacroResolution {
-                        span,
-                        kind: kind.descr(),
-                        path: Segment::names_to_string(path),
-                    });
+                    if this.is_builtin_macro(res)
+                        || this.builtin_attrs_bindings.values().any(|b| b.res() == res)
+                    {
+                        if !this.report_invalid_crate_level_attr(&krate.attrs, path[0].ident.name) {
+                            return;
+                        }
+                        if this.tcx.dcx().has_errors().is_none() {
+                            this.dcx().emit_err(CannotDetermineMacroResolution {
+                                span,
+                                kind: kind.descr(),
+                                path: Segment::names_to_string(path),
+                            });
+                        }
+                    }
                 }
             }
         };

tests/ui/derives/issue-36617.rs

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

tests/ui/derives/issue-36617.stderr

@@ -1,51 +1,8 @@
-error: cannot determine resolution for the attribute macro `derive`
-  --> $DIR/issue-36617.rs:1:4
-   |
-LL | #![derive(Copy)]
-   |    ^^^^^^
-   |
-   = note: import resolution is stuck, try simplifying macro imports
-
-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)]
    | ^^^^^^^^^^^^^^^^
-...
-LL | fn main() {}
-   |    ---- the inner attribute doesn't annotate this function
    |
 help: perhaps you meant to use an outer attribute
    |
@@ -58,9 +15,6 @@ error: `test` attribute cannot be used at crate level
    |
 LL | #![test]
    | ^^^^^^^^
-...
-LL | fn main() {}
-   |    ---- the inner attribute doesn't annotate this function
    |
 help: perhaps you meant to use an outer attribute
    |
@@ -73,9 +27,6 @@ error: `test_case` attribute cannot be used at crate level
    |
 LL | #![test_case]
    | ^^^^^^^^^^^^^
-...
-LL | fn main() {}
-   |    ---- the inner attribute doesn't annotate this function
    |
 help: perhaps you meant to use an outer attribute
    |
@@ -88,9 +39,6 @@ error: `bench` attribute cannot be used at crate level
    |
 LL | #![bench]
    | ^^^^^^^^^
-...
-LL | fn main() {}
-   |    ---- the inner attribute doesn't annotate this function
    |
 help: perhaps you meant to use an outer attribute
    |
@@ -103,15 +51,12 @@ error: `global_allocator` attribute cannot be used at crate level
    |
 LL | #![global_allocator]
    | ^^^^^^^^^^^^^^^^^^^^
-...
-LL | fn main() {}
-   |    ---- the inner attribute doesn't annotate this function
    |
 help: perhaps you meant to use an outer attribute
    |
 LL - #![global_allocator]
 LL + #[global_allocator]
    |
 
-error: aborting due to 10 previous errors
+error: aborting due to 5 previous errors