Rollup merge of rust-lang#104856 - luqmana:associated-const-bad-suggestion, r=compiler-errors

Don't suggest associated function call for associated const.

Fixes rust-lang#104801.

r? `@compiler-errors`

Author: matthiaskrgr

compiler/rustc_hir_typeck/src/method/probe.rs

@@ -9,7 +9,6 @@ use rustc_data_structures::fx::FxHashSet;
 use rustc_errors::Applicability;
 use rustc_hir as hir;
 use rustc_hir::def::DefKind;
-use rustc_hir::def::Namespace;
 use rustc_infer::infer::canonical::OriginalQueryValues;
 use rustc_infer::infer::canonical::{Canonical, QueryResponse};
 use rustc_infer::infer::type_variable::{TypeVariableOrigin, TypeVariableOriginKind};
@@ -1876,6 +1875,15 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> {
         self.tcx.erase_late_bound_regions(value)
     }
 
+    /// Determine if the given associated item type is relevant in the current context.
+    fn is_relevant_kind_for_mode(&self, kind: ty::AssocKind) -> bool {
+        match (self.mode, kind) {
+            (Mode::MethodCall, ty::AssocKind::Fn) => true,
+            (Mode::Path, ty::AssocKind::Const | ty::AssocKind::Fn) => true,
+            _ => false,
+        }
+    }
+
     /// Finds the method with the appropriate name (or return type, as the case may be). If
     /// `allow_similar_names` is set, find methods with close-matching names.
     // The length of the returned iterator is nearly always 0 or 1 and this
@@ -1888,7 +1896,7 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> {
                     .associated_items(def_id)
                     .in_definition_order()
                     .filter(|x| {
-                        if x.kind.namespace() != Namespace::ValueNS {
+                        if !self.is_relevant_kind_for_mode(x.kind) {
                             return false;
                         }
                         match lev_distance_with_substrings(name.as_str(), x.name.as_str(), max_dist)
@@ -1902,10 +1910,16 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> {
             } else {
                 self.fcx
                     .associated_value(def_id, name)
+                    .filter(|x| self.is_relevant_kind_for_mode(x.kind))
                     .map_or_else(SmallVec::new, |x| SmallVec::from_buf([x]))
             }
         } else {
-            self.tcx.associated_items(def_id).in_definition_order().copied().collect()
+            self.tcx
+                .associated_items(def_id)
+                .in_definition_order()
+                .filter(|x| self.is_relevant_kind_for_mode(x.kind))
+                .copied()
+                .collect()
         }
     }
 }

src/test/ui/suggestions/dont-suggest-ufcs-for-const.stderr

@@ -2,13 +2,7 @@ error[E0599]: no method named `MAX` found for type `u32` in the current scope
   --> $DIR/dont-suggest-ufcs-for-const.rs:2:11
    |
 LL |     1_u32.MAX();
-   |     ------^^^--
-   |     |     |
-   |     |     this is an associated function, not a method
-   |     help: use associated function syntax instead: `u32::MAX()`
-   |
-   = note: found the following associated functions; to be used as methods, functions must have a `self` parameter
-   = note: the candidate is defined in an impl for the type `u32`
+   |           ^^^ method not found in `u32`
 
 error: aborting due to previous error