Use FmtPrinter instead of creating Instance

compiler/rustc_hir_typeck/src/method/suggest.rs

@@ -22,7 +22,9 @@ use rustc_middle::infer::unify_key::{ConstVariableOrigin, ConstVariableOriginKin
 use rustc_middle::traits::util::supertraits;
 use rustc_middle::ty::fast_reject::{simplify_type, TreatParams};
 use rustc_middle::ty::print::with_crate_prefix;
-use rustc_middle::ty::{self, DefIdTree, GenericArgKind, ToPredicate, Ty, TyCtxt, TypeVisitable};
+use rustc_middle::ty::{
+    self, DefIdTree, GenericArg, GenericArgKind, ToPredicate, Ty, TyCtxt, TypeVisitable,
+};
 use rustc_middle::ty::{IsSuggestable, ToPolyTraitRef};
 use rustc_span::symbol::{kw, sym, Ident};
 use rustc_span::Symbol;
@@ -283,7 +285,6 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 ) {
                     return None;
                 }
-
                 span = item_name.span;
 
                 // Don't show generic arguments when the method can't be found in any implementation (#81576).
@@ -407,35 +408,41 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                             (ty::Adt(def, _), ty::Adt(def_actual, substs)) if def == def_actual => {
                                 // If there are any inferred arguments, (`{integer}`), we should replace
                                 // them with underscores to allow the compiler to infer them
-                                let substs = substs
+                                let infer_substs: Vec<GenericArg<'_>> = substs
                                     .into_iter()
-                                    .filter(|arg| !arg.is_suggestable(tcx, true))
+                                    .map(|arg| {
-                                    .map(|arg| match arg.unpack() {
+                                        if !arg.is_suggestable(tcx, true) {
-                                        GenericArgKind::Lifetime(_) => self
+                                            match arg.unpack() {
-                                            .next_region_var(RegionVariableOrigin::MiscVariable(
+                                            GenericArgKind::Lifetime(_) => self
-                                                rustc_span::DUMMY_SP,
+                                                .next_region_var(RegionVariableOrigin::MiscVariable(
-                                            ))
+                                                    rustc_span::DUMMY_SP,
-                                            .into(),
+                                                ))
-                                        GenericArgKind::Type(_) => self
+                                                .into(),
-                                            .next_ty_var(TypeVariableOrigin {
+                                            GenericArgKind::Type(_) => self
-                                                span: rustc_span::DUMMY_SP,
+                                                .next_ty_var(TypeVariableOrigin {
-                                                kind: TypeVariableOriginKind::MiscVariable,
-                                            })
-                                            .into(),
-                                        GenericArgKind::Const(arg) => self
-                                            .next_const_var(
-                                                arg.ty(),
-                                                ConstVariableOrigin {
                                                     span: rustc_span::DUMMY_SP,
-                                                    kind: ConstVariableOriginKind::MiscVariable,
+                                                    kind: TypeVariableOriginKind::MiscVariable,
-                                                },
+                                                })
-                                            )
+                                                .into(),
-                                            .into(),
+                                            GenericArgKind::Const(arg) => self
+                                                .next_const_var(
+                                                    arg.ty(),
+                                                    ConstVariableOrigin {
+                                                        span: rustc_span::DUMMY_SP,
+                                                        kind: ConstVariableOriginKind::MiscVariable,
+                                                    },
+                                                )
+                                                .into(),
+                                            }
+                                        } else {
+                                            arg
+                                        }
                                     })
                                     .collect::<Vec<_>>();
-                                format!(
+
-                                    "{}",
+                                tcx.value_path_str_with_substs(
-                                    ty::Instance::new(def_actual.did(), tcx.intern_substs(&substs))
+                                    def_actual.did(),
+                                    tcx.intern_substs(&infer_substs),
                                 )
                             }
                             _ => self.ty_to_value_string(ty.peel_refs()),
@@ -1861,7 +1868,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
     /// Print out the type for use in value namespace.
     fn ty_to_value_string(&self, ty: Ty<'tcx>) -> String {
         match ty.kind() {
-            ty::Adt(def, substs) => format!("{}", ty::Instance::new(def.did(), substs)),
+            ty::Adt(def, substs) => self.tcx.def_path_str_with_substs(def.did(), substs),
             _ => self.ty_to_string(ty),
         }
     }

compiler/rustc_middle/src/ty/print/pretty.rs

@@ -1659,6 +1659,12 @@ impl<'t> TyCtxt<'t> {
         debug!("def_path_str: def_id={:?}, ns={:?}", def_id, ns);
         FmtPrinter::new(self, ns).print_def_path(def_id, substs).unwrap().into_buffer()
     }
+
+    pub fn value_path_str_with_substs(self, def_id: DefId, substs: &'t [GenericArg<'t>]) -> String {
+        let ns = guess_def_namespace(self, def_id);
+        debug!("value_path_str: def_id={:?}, ns={:?}", def_id, ns);
+        FmtPrinter::new(self, ns).print_value_path(def_id, substs).unwrap().into_buffer()
+    }
 }
 
 impl fmt::Write for FmtPrinter<'_, '_> {

src/test/ui/suggestions/suggest-assoc-fn-call-with-turbofish.rs

@@ -2,10 +2,25 @@ struct GenericAssocMethod<T>(T);
 
 impl<T> GenericAssocMethod<T> {
     fn default_hello() {}
+    fn self_ty_hello(_: T) {}
+    fn self_ty_ref_hello(_: &T) {}
 }
 
 fn main() {
-    let x = GenericAssocMethod(33i32);
+    // Test for inferred types
+    let x = GenericAssocMethod(33);
     x.default_hello();
     //~^ ERROR no method named `default_hello` found
+    x.self_ty_ref_hello();
+    //~^ ERROR no method named `self_ty_ref_hello` found
+    x.self_ty_hello();
+    //~^ ERROR no method named `self_ty_hello` found
+    // Test for known types
+    let y = GenericAssocMethod(33i32);
+    y.default_hello();
+    //~^ ERROR no method named `default_hello` found
+    y.self_ty_ref_hello();
+    //~^ ERROR no method named `self_ty_ref_hello` found
+    y.self_ty_hello();
+    //~^ ERROR no method named `self_ty_hello` found
 }

src/test/ui/suggestions/suggest-assoc-fn-call-with-turbofish.stderr

@@ -1,5 +1,5 @@
-error[E0599]: no method named `default_hello` found for struct `GenericAssocMethod<i32>` in the current scope
+error[E0599]: no method named `default_hello` found for struct `GenericAssocMethod<{integer}>` in the current scope
-  --> $DIR/suggest-assoc-fn-call-with-turbofish.rs:9:7
+  --> $DIR/suggest-assoc-fn-call-with-turbofish.rs:12:7
    |
 LL | struct GenericAssocMethod<T>(T);
    | ---------------------------- method `default_hello` not found for this struct
@@ -8,7 +8,7 @@ LL |     x.default_hello();
    |     --^^^^^^^^^^^^^
    |     | |
    |     | this is an associated function, not a method
-   |     help: use associated function syntax instead: `GenericAssocMethod::default_hello`
+   |     help: use associated function syntax instead: `GenericAssocMethod::<_>::default_hello`
    |
    = 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 `GenericAssocMethod<T>`
@@ -17,6 +17,101 @@ note: the candidate is defined in an impl for the type `GenericAssocMethod<T>`
 LL |     fn default_hello() {}
    |     ^^^^^^^^^^^^^^^^^^
 
-error: aborting due to previous error
+error[E0599]: no method named `self_ty_ref_hello` found for struct `GenericAssocMethod<{integer}>` in the current scope
+  --> $DIR/suggest-assoc-fn-call-with-turbofish.rs:14:7
+   |
+LL | struct GenericAssocMethod<T>(T);
+   | ---------------------------- method `self_ty_ref_hello` not found for this struct
+...
+LL |     x.self_ty_ref_hello();
+   |     --^^^^^^^^^^^^^^^^^
+   |     | |
+   |     | this is an associated function, not a method
+   |     help: use associated function syntax instead: `GenericAssocMethod::<_>::self_ty_ref_hello`
+   |
+   = 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 `GenericAssocMethod<T>`
+  --> $DIR/suggest-assoc-fn-call-with-turbofish.rs:6:5
+   |
+LL |     fn self_ty_ref_hello(_: &T) {}
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error[E0599]: no method named `self_ty_hello` found for struct `GenericAssocMethod<{integer}>` in the current scope
+  --> $DIR/suggest-assoc-fn-call-with-turbofish.rs:16:7
+   |
+LL | struct GenericAssocMethod<T>(T);
+   | ---------------------------- method `self_ty_hello` not found for this struct
+...
+LL |     x.self_ty_hello();
+   |     --^^^^^^^^^^^^^
+   |     | |
+   |     | this is an associated function, not a method
+   |     help: use associated function syntax instead: `GenericAssocMethod::<_>::self_ty_hello`
+   |
+   = 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 `GenericAssocMethod<T>`
+  --> $DIR/suggest-assoc-fn-call-with-turbofish.rs:5:5
+   |
+LL |     fn self_ty_hello(_: T) {}
+   |     ^^^^^^^^^^^^^^^^^^^^^^
+
+error[E0599]: no method named `default_hello` found for struct `GenericAssocMethod<i32>` in the current scope
+  --> $DIR/suggest-assoc-fn-call-with-turbofish.rs:20:7
+   |
+LL | struct GenericAssocMethod<T>(T);
+   | ---------------------------- method `default_hello` not found for this struct
+...
+LL |     y.default_hello();
+   |     --^^^^^^^^^^^^^
+   |     | |
+   |     | this is an associated function, not a method
+   |     help: use associated function syntax instead: `GenericAssocMethod::<i32>::default_hello`
+   |
+   = 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 `GenericAssocMethod<T>`
+  --> $DIR/suggest-assoc-fn-call-with-turbofish.rs:4:5
+   |
+LL |     fn default_hello() {}
+   |     ^^^^^^^^^^^^^^^^^^
+
+error[E0599]: no method named `self_ty_ref_hello` found for struct `GenericAssocMethod<i32>` in the current scope
+  --> $DIR/suggest-assoc-fn-call-with-turbofish.rs:22:7
+   |
+LL | struct GenericAssocMethod<T>(T);
+   | ---------------------------- method `self_ty_ref_hello` not found for this struct
+...
+LL |     y.self_ty_ref_hello();
+   |     --^^^^^^^^^^^^^^^^^
+   |     | |
+   |     | this is an associated function, not a method
+   |     help: use associated function syntax instead: `GenericAssocMethod::<i32>::self_ty_ref_hello`
+   |
+   = 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 `GenericAssocMethod<T>`
+  --> $DIR/suggest-assoc-fn-call-with-turbofish.rs:6:5
+   |
+LL |     fn self_ty_ref_hello(_: &T) {}
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error[E0599]: no method named `self_ty_hello` found for struct `GenericAssocMethod<i32>` in the current scope
+  --> $DIR/suggest-assoc-fn-call-with-turbofish.rs:24:7
+   |
+LL | struct GenericAssocMethod<T>(T);
+   | ---------------------------- method `self_ty_hello` not found for this struct
+...
+LL |     y.self_ty_hello();
+   |     --^^^^^^^^^^^^^
+   |     | |
+   |     | this is an associated function, not a method
+   |     help: use associated function syntax instead: `GenericAssocMethod::<i32>::self_ty_hello`
+   |
+   = 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 `GenericAssocMethod<T>`
+  --> $DIR/suggest-assoc-fn-call-with-turbofish.rs:5:5
+   |
+LL |     fn self_ty_hello(_: T) {}
+   |     ^^^^^^^^^^^^^^^^^^^^^^
+
+error: aborting due to 6 previous errors
 
 For more information about this error, try `rustc --explain E0599`.