Only suggest call on nonexistent fields and methods if they make sense

Author: compiler-errors

compiler/rustc_typeck/src/check/expr.rs

@@ -21,7 +21,6 @@ use crate::errors::{
 };
 use crate::type_error_struct;
 
-use super::suggest_call_constructor;
 use crate::errors::{AddressOfTemporaryTaken, ReturnStmtOutsideOfFnBody, StructExprNonExhaustive};
 use rustc_ast as ast;
 use rustc_data_structures::fx::FxHashMap;
@@ -44,7 +43,7 @@ use rustc_middle::middle::stability;
 use rustc_middle::ty::adjustment::{Adjust, Adjustment, AllowTwoPhase};
 use rustc_middle::ty::error::TypeError::FieldMisMatch;
 use rustc_middle::ty::subst::SubstsRef;
-use rustc_middle::ty::{self, AdtKind, DefIdTree, Ty, TypeVisitable};
+use rustc_middle::ty::{self, AdtKind, Ty, TypeVisitable};
 use rustc_session::parse::feature_err;
 use rustc_span::hygiene::DesugaringKind;
 use rustc_span::lev_distance::find_best_match_for_name;
@@ -2280,35 +2279,6 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         self.tcx().ty_error()
     }
 
-    fn check_call_constructor(
-        &self,
-        err: &mut Diagnostic,
-        base: &'tcx hir::Expr<'tcx>,
-        def_id: DefId,
-    ) {
-        if let Some(local_id) = def_id.as_local() {
-            let hir_id = self.tcx.hir().local_def_id_to_hir_id(local_id);
-            let node = self.tcx.hir().get(hir_id);
-
-            if let Some(fields) = node.tuple_fields() {
-                let kind = match self.tcx.opt_def_kind(local_id) {
-                    Some(DefKind::Ctor(of, _)) => of,
-                    _ => return,
-                };
-
-                suggest_call_constructor(base.span, kind, fields.len(), err);
-            }
-        } else {
-            // The logic here isn't smart but `associated_item_def_ids`
-            // doesn't work nicely on local.
-            if let DefKind::Ctor(of, _) = self.tcx.def_kind(def_id) {
-                let parent_def_id = self.tcx.parent(def_id);
-                let fields = self.tcx.associated_item_def_ids(parent_def_id);
-                suggest_call_constructor(base.span, of, fields.len(), err);
-            }
-        }
-    }
-
     fn suggest_await_on_field_access(
         &self,
         err: &mut Diagnostic,
@@ -2378,12 +2348,24 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             ty::Opaque(_, _) => {
                 self.suggest_await_on_field_access(&mut err, ident, base, base_ty.peel_refs());
             }
-            ty::FnDef(def_id, _) => {
-                self.check_call_constructor(&mut err, base, def_id);
-            }
             _ => {}
         }
 
+        self.suggest_fn_call(&mut err, base, base_ty, |output_ty| {
+            if let ty::Adt(def, _) = output_ty.kind() && !def.is_enum() {
+                def.non_enum_variant().fields.iter().any(|field| {
+                    field.ident(self.tcx) == ident
+                        && field.vis.is_accessible_from(expr.hir_id.owner.to_def_id(), self.tcx)
+                })
+            } else if let ty::Tuple(tys) = output_ty.kind()
+                && let Ok(idx) = ident.as_str().parse::<usize>()
+            {
+                idx < tys.len()
+            } else {
+                false
+            }
+        });
+
         if ident.name == kw::Await {
             // We know by construction that `<expr>.await` is either on Rust 2015
             // or results in `ExprKind::Await`. Suggest switching the edition to 2018.

compiler/rustc_typeck/src/check/method/suggest.rs

@@ -31,7 +31,7 @@ use std::cmp::Ordering;
 use std::iter;
 
 use super::probe::{Mode, ProbeScope};
-use super::{super::suggest_call_constructor, CandidateSource, MethodError, NoMatchData};
+use super::{CandidateSource, MethodError, NoMatchData};
 
 impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
     fn is_fn_ty(&self, ty: Ty<'tcx>, span: Span) -> bool {
@@ -363,44 +363,21 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     );
                 }
 
-                if self.is_fn_ty(rcvr_ty, span) {
-                    if let SelfSource::MethodCall(expr) = source {
-                        let suggest = if let ty::FnDef(def_id, _) = rcvr_ty.kind() {
-                            if let Some(local_id) = def_id.as_local() {
-                                let hir_id = tcx.hir().local_def_id_to_hir_id(local_id);
-                                let node = tcx.hir().get(hir_id);
-                                let fields = node.tuple_fields();
-                                if let Some(fields) = fields
-                                    && let Some(DefKind::Ctor(of, _)) = self.tcx.opt_def_kind(local_id) {
-                                        Some((fields.len(), of))
-                                } else {
-                                    None
-                                }
-                            } else {
-                                // The logic here isn't smart but `associated_item_def_ids`
-                                // doesn't work nicely on local.
-                                if let DefKind::Ctor(of, _) = tcx.def_kind(def_id) {
-                                    let parent_def_id = tcx.parent(*def_id);
-                                    Some((tcx.associated_item_def_ids(parent_def_id).len(), of))
-                                } else {
-                                    None
-                                }
-                            }
-                        } else {
-                            None
-                        };
-
-                        // If the function is a tuple constructor, we recommend that they call it
-                        if let Some((fields, kind)) = suggest {
-                            suggest_call_constructor(expr.span, kind, fields, &mut err);
-                        } else {
-                            // General case
-                            err.span_label(
-                                expr.span,
-                                "this is a function, perhaps you wish to call it",
-                            );
-                        }
-                    }
+                if let SelfSource::MethodCall(rcvr_expr) = source {
+                    self.suggest_fn_call(&mut err, rcvr_expr, rcvr_ty, |output_ty| {
+                        let call_expr = self
+                            .tcx
+                            .hir()
+                            .expect_expr(self.tcx.hir().get_parent_node(rcvr_expr.hir_id));
+                        let probe = self.lookup_probe(
+                            span,
+                            item_name,
+                            output_ty,
+                            call_expr,
+                            ProbeScope::AllTraits,
+                        );
+                        probe.is_ok()
+                    });
                 }
 
                 let mut custom_span_label = false;

compiler/rustc_typeck/src/check/mod.rs

@@ -96,7 +96,6 @@ use check::{check_abi, check_fn, check_mod_item_types};
 pub use diverges::Diverges;
 pub use expectation::Expectation;
 pub use fn_ctxt::*;
-use hir::def::CtorOf;
 pub use inherited::{Inherited, InheritedBuilder};
 
 use crate::astconv::AstConv;
@@ -960,31 +959,3 @@ fn has_expected_num_generic_args<'tcx>(
         generics.count() == expected + if generics.has_self { 1 } else { 0 }
     })
 }
-
-/// Suggests calling the constructor of a tuple struct or enum variant
-///
-/// * `snippet` - The snippet of code that references the constructor
-/// * `span` - The span of the snippet
-/// * `params` - The number of parameters the constructor accepts
-/// * `err` - A mutable diagnostic builder to add the suggestion to
-fn suggest_call_constructor(span: Span, kind: CtorOf, params: usize, err: &mut Diagnostic) {
-    // Note: tuple-structs don't have named fields, so just use placeholders
-    let args = vec!["_"; params].join(", ");
-    let applicable = if params > 0 {
-        Applicability::HasPlaceholders
-    } else {
-        // When n = 0, it's an empty-tuple struct/enum variant
-        // so we trivially know how to construct it
-        Applicability::MachineApplicable
-    };
-    let kind = match kind {
-        CtorOf::Struct => "a struct",
-        CtorOf::Variant => "an enum variant",
-    };
-    err.span_label(span, &format!("this is the constructor of {kind}"));
-    err.multipart_suggestion(
-        "call the constructor",
-        vec![(span.shrink_to_lo(), "(".to_string()), (span.shrink_to_hi(), format!(")({args})"))],
-        applicable,
-    );
-}

src/test/ui/functions-closures/fn-help-with-err.rs

@@ -1,16 +1,28 @@
 // This test case checks the behavior of typeck::check::method::suggest::is_fn on Ty::Error.
+
+struct Foo;
+
+trait Bar {
+    //~^ NOTE `Bar` defines an item `bar`, perhaps you need to implement it
+    //~| NOTE `Bar` defines an item `bar`, perhaps you need to implement it
+    fn bar(&self) {}
+}
+
+impl Bar for Foo {}
+
 fn main() {
     let arc = std::sync::Arc::new(oops);
     //~^ ERROR cannot find value `oops` in this scope
     //~| NOTE not found
-    // The error "note: this is a function, perhaps you wish to call it" MUST NOT appear.
-    arc.blablabla();
-    //~^ ERROR no method named `blablabla`
+    arc.bar();
+    //~^ ERROR no method named `bar`
     //~| NOTE method not found
-    let arc2 = std::sync::Arc::new(|| 1);
-    // The error "note: this is a function, perhaps you wish to call it" SHOULD appear
-    arc2.blablabla();
-    //~^ ERROR no method named `blablabla`
+    //~| HELP items from traits can only be used if the trait is implemented and in scope
+
+    let arc2 = std::sync::Arc::new(|| Foo);
+    arc2.bar();
+    //~^ ERROR no method named `bar`
     //~| NOTE method not found
-    //~| NOTE this is a function, perhaps you wish to call it
+    //~| HELP items from traits can only be used if the trait is implemented and in scope
+    //~| HELP use parentheses to call this closure
 }

src/test/ui/functions-closures/fn-help-with-err.stderr

@@ -1,22 +1,38 @@
 error[E0425]: cannot find value `oops` in this scope
-  --> $DIR/fn-help-with-err.rs:3:35
+  --> $DIR/fn-help-with-err.rs:14:35
    |
 LL |     let arc = std::sync::Arc::new(oops);
    |                                   ^^^^ not found in this scope
 
-error[E0599]: no method named `blablabla` found for struct `Arc<_>` in the current scope
-  --> $DIR/fn-help-with-err.rs:7:9
+error[E0599]: no method named `bar` found for struct `Arc<_>` in the current scope
+  --> $DIR/fn-help-with-err.rs:17:9
    |
-LL |     arc.blablabla();
-   |         ^^^^^^^^^ method not found in `Arc<_>`
+LL |     arc.bar();
+   |         ^^^ method not found in `Arc<_>`
+   |
+   = help: items from traits can only be used if the trait is implemented and in scope
+note: `Bar` defines an item `bar`, perhaps you need to implement it
+  --> $DIR/fn-help-with-err.rs:5:1
+   |
+LL | trait Bar {
+   | ^^^^^^^^^
 
-error[E0599]: no method named `blablabla` found for struct `Arc<[closure@$DIR/fn-help-with-err.rs:10:36: 10:38]>` in the current scope
-  --> $DIR/fn-help-with-err.rs:12:10
+error[E0599]: no method named `bar` found for struct `Arc<[closure@$DIR/fn-help-with-err.rs:22:36: 22:38]>` in the current scope
+  --> $DIR/fn-help-with-err.rs:23:10
+   |
+LL |     arc2.bar();
+   |          ^^^ method not found in `Arc<[closure@$DIR/fn-help-with-err.rs:22:36: 22:38]>`
+   |
+   = help: items from traits can only be used if the trait is implemented and in scope
+note: `Bar` defines an item `bar`, perhaps you need to implement it
+  --> $DIR/fn-help-with-err.rs:5:1
+   |
+LL | trait Bar {
+   | ^^^^^^^^^
+help: use parentheses to call this closure
    |
-LL |     arc2.blablabla();
-   |     ---- ^^^^^^^^^ method not found in `Arc<[closure@$DIR/fn-help-with-err.rs:10:36: 10:38]>`
-   |     |
-   |     this is a function, perhaps you wish to call it
+LL |     arc2().bar();
+   |         ++
 
 error: aborting due to 3 previous errors
 

src/test/ui/issues/issue-57362-1.stderr

@@ -2,9 +2,7 @@ error[E0599]: no method named `f` found for fn pointer `fn(&u8)` in the current
   --> $DIR/issue-57362-1.rs:20:7
    |
 LL |     a.f();
-   |     - ^ method not found in `fn(&u8)`
-   |     |
-   |     this is a function, perhaps you wish to call it
+   |       ^ method not found in `fn(&u8)`
    |
    = help: items from traits can only be used if the trait is implemented and in scope
 note: `Trait` defines an item `f`, perhaps you need to implement it

src/test/ui/typeck/issue-29124.stderr

@@ -2,17 +2,13 @@ error[E0599]: no method named `x` found for fn item `fn() -> Ret {Obj::func}` in
   --> $DIR/issue-29124.rs:15:15
    |
 LL |     Obj::func.x();
-   |     --------- ^ method not found in `fn() -> Ret {Obj::func}`
-   |     |
-   |     this is a function, perhaps you wish to call it
+   |               ^ method not found in `fn() -> Ret {Obj::func}`
 
 error[E0599]: no method named `x` found for fn item `fn() -> Ret {func}` in the current scope
   --> $DIR/issue-29124.rs:17:10
    |
 LL |     func.x();
-   |     ---- ^ method not found in `fn() -> Ret {func}`
-   |     |
-   |     this is a function, perhaps you wish to call it
+   |          ^ method not found in `fn() -> Ret {func}`
 
 error: aborting due to 2 previous errors
 

src/test/ui/typeck/issue-87181/empty-tuple-method.rs

@@ -4,7 +4,7 @@ struct Bar<T> {
 
 struct Foo();
 impl Foo {
-    fn foo() { }
+    fn foo(&self) { }
 }
 
 fn main() {

src/test/ui/typeck/issue-87181/empty-tuple-method.stderr

@@ -2,11 +2,9 @@ error[E0599]: no method named `foo` found for fn item `fn() -> Foo {Foo}` in the
   --> $DIR/empty-tuple-method.rs:12:15
    |
 LL |     thing.bar.foo();
-   |     --------- ^^^ method not found in `fn() -> Foo {Foo}`
-   |     |
-   |     this is the constructor of a struct
+   |               ^^^ method not found in `fn() -> Foo {Foo}`
    |
-help: call the constructor
+help: use parentheses to instantiate this tuple struct
    |
 LL |     (thing.bar)().foo();
    |     +         +++

src/test/ui/typeck/issue-87181/enum-variant.rs

@@ -6,7 +6,7 @@ enum Foo{
     Tup()
 }
 impl Foo {
-    fn foo() { }
+    fn foo(&self) { }
 }
 
 fn main() {