resolve: Visit all scopes to collect suggestion candidates for unresolved macros

Author: petrochenkov

src/librustc/hir/def.rs

@@ -398,4 +398,12 @@ impl<Id> Res<Id> {
             Res::Err => Res::Err,
         }
     }
+
+    pub fn macro_kind(self) -> Option<MacroKind> {
+        match self {
+            Res::Def(DefKind::Macro(kind), _) => Some(kind),
+            Res::NonMacroAttr(..) => Some(MacroKind::Attr),
+            _ => None,
+        }
+    }
 }

src/librustc_resolve/diagnostics.rs

@@ -85,9 +85,7 @@ mod check_unused;
 mod build_reduced_graph;
 mod resolve_imports;
 
-fn is_known_tool(name: Name) -> bool {
-    ["clippy", "rustfmt"].contains(&&*name.as_str())
-}
+const KNOWN_TOOLS: &[Name] = &[sym::clippy, sym::rustfmt];
 
 enum Weak {
     Yes,
@@ -1498,11 +1496,7 @@ impl<'a> NameBinding<'a> {
     }
 
     fn macro_kind(&self) -> Option<MacroKind> {
-        match self.res() {
-            Res::Def(DefKind::Macro(kind), _) => Some(kind),
-            Res::NonMacroAttr(..) => Some(MacroKind::Attr),
-            _ => None,
-        }
+        self.res().macro_kind()
     }
 
     fn descr(&self) -> &'static str {
@@ -2390,7 +2384,7 @@ impl<'a> Resolver<'a> {
                     return Some(LexicalScopeBinding::Item(binding));
                 }
             }
-            if ns == TypeNS && is_known_tool(ident.name) {
+            if ns == TypeNS && KNOWN_TOOLS.contains(&ident.name) {
                 let binding = (Res::ToolMod, ty::Visibility::Public,
                                DUMMY_SP, Mark::root()).to_name_binding(self.arenas);
                 return Some(LexicalScopeBinding::Item(binding));

src/librustc_resolve/lib.rs

@@ -1,7 +1,7 @@
 use crate::{AmbiguityError, AmbiguityKind, AmbiguityErrorMisc, Determinacy};
 use crate::{CrateLint, Resolver, ResolutionError, Scope, ScopeSet, ParentScope, Weak};
 use crate::{Module, ModuleKind, NameBinding, NameBindingKind, PathResult, Segment, ToNameBinding};
-use crate::{is_known_tool, resolve_error};
+use crate::{resolve_error, KNOWN_TOOLS};
 use crate::ModuleOrUniformRoot;
 use crate::Namespace::*;
 use crate::build_reduced_graph::{BuildReducedGraphVisitor, IsMacroExport};
@@ -57,10 +57,10 @@ impl<'a> InvocationData<'a> {
 /// Not modularized, can shadow previous legacy bindings, etc.
 #[derive(Debug)]
 pub struct LegacyBinding<'a> {
-    binding: &'a NameBinding<'a>,
+    crate binding: &'a NameBinding<'a>,
     /// Legacy scope into which the `macro_rules` item was planted.
     crate parent_legacy_scope: LegacyScope<'a>,
-    ident: Ident,
+    crate ident: Ident,
 }
 
 /// The scope introduced by a `macro_rules!` macro.
@@ -582,7 +582,7 @@ impl<'a> Resolver<'a> {
                     }
                 }
                 Scope::ToolPrelude => {
-                    if use_prelude && is_known_tool(ident.name) {
+                    if use_prelude && KNOWN_TOOLS.contains(&ident.name) {
                         let binding = (Res::ToolMod, ty::Visibility::Public,
                                        DUMMY_SP, Mark::root()).to_name_binding(this.arenas);
                         Ok((binding, Flags::PRELUDE))
@@ -805,7 +805,7 @@ impl<'a> Resolver<'a> {
                     let msg =
                         format!("cannot find {} `{}{}` in this scope", kind.descr(), ident, bang);
                     let mut err = self.session.struct_span_err(ident.span, &msg);
-                    self.suggest_macro_name(ident.name, kind, &mut err, ident.span);
+                    self.unresolved_macro_suggestions(&mut err, kind, &parent_scope, ident);
                     err.emit();
                 }
             }

src/librustc_resolve/macros.rs

@@ -603,6 +603,7 @@ symbols! {
         rustc_then_this_would_need,
         rustc_variance,
         rustdoc,
+        rustfmt,
         rust_eh_personality,
         rust_eh_unwind_resume,
         rust_oom,

src/libsyntax_pos/symbol.rs

@@ -2,7 +2,7 @@ error: cannot find derive macro `Eqr` in this scope
   --> $DIR/deriving-meta-unknown-trait.rs:1:10
    |
 LL | #[derive(Eqr)]
-   |          ^^^ help: try: `Eq`
+   |          ^^^ help: a derive macro with a similar name exists: `Eq`
 
 error: aborting due to previous error
 

src/test/ui/derives/deriving-meta-unknown-trait.stderr

@@ -3,8 +3,6 @@ error: cannot find macro `print!` in this scope
    |
 LL |         print!();
    |         ^^^^^
-   |
-   = help: have you added the `#[macro_use]` on the module/import?
 
 error: aborting due to previous error
 

src/test/ui/hygiene/no_implicit_prelude-2018.stderr

@@ -13,7 +13,6 @@ error: cannot find macro `panic!` in this scope
 LL |         assert_eq!(0, 0);
    |         ^^^^^^^^^^^^^^^^^
    |
-   = help: have you added the `#[macro_use]` on the module/import?
    = note: this error originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)
 
 error[E0599]: no method named `clone` found for type `()` in the current scope

src/test/ui/hygiene/no_implicit_prelude.stderr

@@ -2,7 +2,7 @@ error: cannot find attribute macro `marco_use` in this scope
   --> $DIR/issue-49074.rs:3:3
    |
 LL | #[marco_use] // typo
-   |   ^^^^^^^^^
+   |   ^^^^^^^^^ help: a built-in attribute with a similar name exists: `macro_use`
 
 error: cannot find macro `bar!` in this scope
   --> $DIR/issue-49074.rs:12:4

src/test/ui/issues/issue-49074.stderr

@@ -2,7 +2,7 @@ error: cannot find macro `printlx!` in this scope
   --> $DIR/macro-name-typo.rs:2:5
    |
 LL |     printlx!("oh noes!");
-   |     ^^^^^^^ help: you could try the macro: `println`
+   |     ^^^^^^^ help: a macro with a similar name exists: `println`
 
 error: aborting due to previous error