Do not suggest path::to<impl Trait for Type>::method

estebank · estebank · commit d697d635fc96 · 2024-08-04T15:56:18.000Z
In the pretty-printer, we have a weird way to display fully-qualified for non-local impls, where we show a regular path, but the section corresponding to the `&lt;Type as Trait&gt;` we use non-syntax for it like `path::to&lt;impl Trait for Type&gt;`. It should be `&lt;Type for path::to::Trait&gt;`, but this is only better when we are printing code to be suggested, not to find where the `impl` actually is, so we add a new flag to the printer for this.
diff --git a/compiler/rustc_middle/src/ty/print/mod.rs b/compiler/rustc_middle/src/ty/print/mod.rs
@@ -227,7 +227,7 @@ pub trait Printer<'tcx>: Sized {
             Some(trait_ref) => self.tcx().parent(trait_ref.def_id) == parent_def_id,
         };
 
-        if !in_self_mod && !in_trait_mod {
+        if !in_self_mod && !in_trait_mod && !self.for_suggestion() {
             // If the impl is not co-located with either self-type or
             // trait-type, then fallback to a format that identifies
             // the module more clearly.
@@ -243,6 +243,10 @@ pub trait Printer<'tcx>: Sized {
             self.path_qualified(self_ty, impl_trait_ref)
         }
     }
+
+    fn for_suggestion(&self) -> bool {
+        false
+    }
 }
 
 /// As a heuristic, when we see an impl, if we see that the
diff --git a/compiler/rustc_middle/src/ty/print/pretty.rs b/compiler/rustc_middle/src/ty/print/pretty.rs
@@ -2010,6 +2010,7 @@ pub struct FmtPrinterData<'a, 'tcx> {
 
     pub ty_infer_name_resolver: Option<Box<dyn Fn(ty::TyVid) -> Option<Symbol> + 'a>>,
     pub const_infer_name_resolver: Option<Box<dyn Fn(ty::ConstVid) -> Option<Symbol> + 'a>>,
+    pub for_suggestion: bool,
 }
 
 impl<'a, 'tcx> Deref for FmtPrinter<'a, 'tcx> {
@@ -2060,6 +2061,7 @@ impl<'a, 'tcx> FmtPrinter<'a, 'tcx> {
             region_highlight_mode: RegionHighlightMode::default(),
             ty_infer_name_resolver: None,
             const_infer_name_resolver: None,
+            for_suggestion: false,
         }))
     }
 
@@ -2311,6 +2313,9 @@ impl<'tcx> Printer<'tcx> for FmtPrinter<'_, 'tcx> {
             Ok(())
         }
     }
+    fn for_suggestion(&self) -> bool {
+        self.0.for_suggestion
+    }
 }
 
 impl<'tcx> PrettyPrinter<'tcx> for FmtPrinter<'_, 'tcx> {
diff --git a/compiler/rustc_trait_selection/src/error_reporting/infer/need_type_info.rs b/compiler/rustc_trait_selection/src/error_reporting/infer/need_type_info.rs
@@ -205,6 +205,7 @@ fn fmt_printer<'a, 'tcx>(infcx: &'a InferCtxt<'tcx>, ns: Namespace) -> FmtPrinte
         }
     };
     printer.ty_infer_name_resolver = Some(Box::new(ty_getter));
+    printer.for_suggestion = true;
     let const_getter =
         move |ct_vid| Some(infcx.tcx.item_name(infcx.const_var_origin(ct_vid)?.param_def_id?));
     printer.const_infer_name_resolver = Some(Box::new(const_getter));
diff --git a/tests/ui/inference/issue-72690.stderr b/tests/ui/inference/issue-72690.stderr
@@ -21,20 +21,20 @@ LL |     String::from("x".as_ref());
            - impl AsRef<str> for str;
 help: try using a fully qualified path to specify the expected types
    |
-LL |     String::from(os_str::<impl AsRef<OsStr> for str>::as_ref("x"));
-   |                  ++++++++++++++++++++++++++++++++++++++++++++   ~
+LL |     String::from(<str as AsRef<OsStr>>::as_ref("x"));
+   |                  ++++++++++++++++++++++++++++++   ~
 help: try using a fully qualified path to specify the expected types
    |
-LL |     String::from(path::<impl AsRef<Path> for str>::as_ref("x"));
-   |                  +++++++++++++++++++++++++++++++++++++++++   ~
+LL |     String::from(<str as AsRef<Path>>::as_ref("x"));
+   |                  +++++++++++++++++++++++++++++   ~
 help: try using a fully qualified path to specify the expected types
    |
 LL |     String::from(<str as AsRef<str>>::as_ref("x"));
    |                  ++++++++++++++++++++++++++++   ~
 help: try using a fully qualified path to specify the expected types
    |
-LL |     String::from(core::str::<impl AsRef<[u8]> for str>::as_ref("x"));
-   |                  ++++++++++++++++++++++++++++++++++++++++++++++   ~
+LL |     String::from(<str as AsRef<[u8]>>::as_ref("x"));
+   |                  +++++++++++++++++++++++++++++   ~
 
 error[E0283]: type annotations needed
   --> $DIR/issue-72690.rs:12:9
@@ -59,20 +59,20 @@ LL |     |x| String::from("x".as_ref());
            - impl AsRef<str> for str;
 help: try using a fully qualified path to specify the expected types
    |
-LL |     |x| String::from(os_str::<impl AsRef<OsStr> for str>::as_ref("x"));
-   |                      ++++++++++++++++++++++++++++++++++++++++++++   ~
+LL |     |x| String::from(<str as AsRef<OsStr>>::as_ref("x"));
+   |                      ++++++++++++++++++++++++++++++   ~
 help: try using a fully qualified path to specify the expected types
    |
-LL |     |x| String::from(path::<impl AsRef<Path> for str>::as_ref("x"));
-   |                      +++++++++++++++++++++++++++++++++++++++++   ~
+LL |     |x| String::from(<str as AsRef<Path>>::as_ref("x"));
+   |                      +++++++++++++++++++++++++++++   ~
 help: try using a fully qualified path to specify the expected types
    |
 LL |     |x| String::from(<str as AsRef<str>>::as_ref("x"));
    |                      ++++++++++++++++++++++++++++   ~
 help: try using a fully qualified path to specify the expected types
    |
-LL |     |x| String::from(core::str::<impl AsRef<[u8]> for str>::as_ref("x"));
-   |                      ++++++++++++++++++++++++++++++++++++++++++++++   ~
+LL |     |x| String::from(<str as AsRef<[u8]>>::as_ref("x"));
+   |                      +++++++++++++++++++++++++++++   ~
 
 error[E0283]: type annotations needed for `&_`
   --> $DIR/issue-72690.rs:17:9
@@ -113,20 +113,20 @@ LL |     String::from("x".as_ref());
            - impl AsRef<str> for str;
 help: try using a fully qualified path to specify the expected types
    |
-LL |     String::from(os_str::<impl AsRef<OsStr> for str>::as_ref("x"));
-   |                  ++++++++++++++++++++++++++++++++++++++++++++   ~
+LL |     String::from(<str as AsRef<OsStr>>::as_ref("x"));
+   |                  ++++++++++++++++++++++++++++++   ~
 help: try using a fully qualified path to specify the expected types
    |
-LL |     String::from(path::<impl AsRef<Path> for str>::as_ref("x"));
-   |                  +++++++++++++++++++++++++++++++++++++++++   ~
+LL |     String::from(<str as AsRef<Path>>::as_ref("x"));
+   |                  +++++++++++++++++++++++++++++   ~
 help: try using a fully qualified path to specify the expected types
    |
 LL |     String::from(<str as AsRef<str>>::as_ref("x"));
    |                  ++++++++++++++++++++++++++++   ~
 help: try using a fully qualified path to specify the expected types
    |
-LL |     String::from(core::str::<impl AsRef<[u8]> for str>::as_ref("x"));
-   |                  ++++++++++++++++++++++++++++++++++++++++++++++   ~
+LL |     String::from(<str as AsRef<[u8]>>::as_ref("x"));
+   |                  +++++++++++++++++++++++++++++   ~
 
 error[E0283]: type annotations needed
   --> $DIR/issue-72690.rs:28:5
@@ -151,20 +151,20 @@ LL |     String::from("x".as_ref());
            - impl AsRef<str> for str;
 help: try using a fully qualified path to specify the expected types
    |
-LL |     String::from(os_str::<impl AsRef<OsStr> for str>::as_ref("x"));
-   |                  ++++++++++++++++++++++++++++++++++++++++++++   ~
+LL |     String::from(<str as AsRef<OsStr>>::as_ref("x"));
+   |                  ++++++++++++++++++++++++++++++   ~
 help: try using a fully qualified path to specify the expected types
    |
-LL |     String::from(path::<impl AsRef<Path> for str>::as_ref("x"));
-   |                  +++++++++++++++++++++++++++++++++++++++++   ~
+LL |     String::from(<str as AsRef<Path>>::as_ref("x"));
+   |                  +++++++++++++++++++++++++++++   ~
 help: try using a fully qualified path to specify the expected types
    |
 LL |     String::from(<str as AsRef<str>>::as_ref("x"));
    |                  ++++++++++++++++++++++++++++   ~
 help: try using a fully qualified path to specify the expected types
    |
-LL |     String::from(core::str::<impl AsRef<[u8]> for str>::as_ref("x"));
-   |                  ++++++++++++++++++++++++++++++++++++++++++++++   ~
+LL |     String::from(<str as AsRef<[u8]>>::as_ref("x"));
+   |                  +++++++++++++++++++++++++++++   ~
 
 error[E0283]: type annotations needed
   --> $DIR/issue-72690.rs:37:5
@@ -189,20 +189,20 @@ LL |     String::from("x".as_ref());
            - impl AsRef<str> for str;
 help: try using a fully qualified path to specify the expected types
    |
-LL |     String::from(os_str::<impl AsRef<OsStr> for str>::as_ref("x"));
-   |                  ++++++++++++++++++++++++++++++++++++++++++++   ~
+LL |     String::from(<str as AsRef<OsStr>>::as_ref("x"));
+   |                  ++++++++++++++++++++++++++++++   ~
 help: try using a fully qualified path to specify the expected types
    |
-LL |     String::from(path::<impl AsRef<Path> for str>::as_ref("x"));
-   |                  +++++++++++++++++++++++++++++++++++++++++   ~
+LL |     String::from(<str as AsRef<Path>>::as_ref("x"));
+   |                  +++++++++++++++++++++++++++++   ~
 help: try using a fully qualified path to specify the expected types
    |
 LL |     String::from(<str as AsRef<str>>::as_ref("x"));
    |                  ++++++++++++++++++++++++++++   ~
 help: try using a fully qualified path to specify the expected types
    |
-LL |     String::from(core::str::<impl AsRef<[u8]> for str>::as_ref("x"));
-   |                  ++++++++++++++++++++++++++++++++++++++++++++++   ~
+LL |     String::from(<str as AsRef<[u8]>>::as_ref("x"));
+   |                  +++++++++++++++++++++++++++++   ~
 
 error[E0283]: type annotations needed
   --> $DIR/issue-72690.rs:46:5
@@ -227,20 +227,20 @@ LL |     String::from("x".as_ref());
            - impl AsRef<str> for str;
 help: try using a fully qualified path to specify the expected types
    |
-LL |     String::from(os_str::<impl AsRef<OsStr> for str>::as_ref("x"));
-   |                  ++++++++++++++++++++++++++++++++++++++++++++   ~
+LL |     String::from(<str as AsRef<OsStr>>::as_ref("x"));
+   |                  ++++++++++++++++++++++++++++++   ~
 help: try using a fully qualified path to specify the expected types
    |
-LL |     String::from(path::<impl AsRef<Path> for str>::as_ref("x"));
-   |                  +++++++++++++++++++++++++++++++++++++++++   ~
+LL |     String::from(<str as AsRef<Path>>::as_ref("x"));
+   |                  +++++++++++++++++++++++++++++   ~
 help: try using a fully qualified path to specify the expected types
    |
 LL |     String::from(<str as AsRef<str>>::as_ref("x"));
    |                  ++++++++++++++++++++++++++++   ~
 help: try using a fully qualified path to specify the expected types
    |
-LL |     String::from(core::str::<impl AsRef<[u8]> for str>::as_ref("x"));
-   |                  ++++++++++++++++++++++++++++++++++++++++++++++   ~
+LL |     String::from(<str as AsRef<[u8]>>::as_ref("x"));
+   |                  +++++++++++++++++++++++++++++   ~
 
 error[E0283]: type annotations needed
   --> $DIR/issue-72690.rs:53:5
@@ -265,20 +265,20 @@ LL |     String::from("x".as_ref());
            - impl AsRef<str> for str;
 help: try using a fully qualified path to specify the expected types
    |
-LL |     String::from(os_str::<impl AsRef<OsStr> for str>::as_ref("x"));
-   |                  ++++++++++++++++++++++++++++++++++++++++++++   ~
+LL |     String::from(<str as AsRef<OsStr>>::as_ref("x"));
+   |                  ++++++++++++++++++++++++++++++   ~
 help: try using a fully qualified path to specify the expected types
    |
-LL |     String::from(path::<impl AsRef<Path> for str>::as_ref("x"));
-   |                  +++++++++++++++++++++++++++++++++++++++++   ~
+LL |     String::from(<str as AsRef<Path>>::as_ref("x"));
+   |                  +++++++++++++++++++++++++++++   ~
 help: try using a fully qualified path to specify the expected types
    |
 LL |     String::from(<str as AsRef<str>>::as_ref("x"));
    |                  ++++++++++++++++++++++++++++   ~
 help: try using a fully qualified path to specify the expected types
    |
-LL |     String::from(core::str::<impl AsRef<[u8]> for str>::as_ref("x"));
-   |                  ++++++++++++++++++++++++++++++++++++++++++++++   ~
+LL |     String::from(<str as AsRef<[u8]>>::as_ref("x"));
+   |                  +++++++++++++++++++++++++++++   ~
 
 error[E0283]: type annotations needed
   --> $DIR/issue-72690.rs:62:5
@@ -303,20 +303,20 @@ LL |     String::from("x".as_ref());
            - impl AsRef<str> for str;
 help: try using a fully qualified path to specify the expected types
    |
-LL |     String::from(os_str::<impl AsRef<OsStr> for str>::as_ref("x"));
-   |                  ++++++++++++++++++++++++++++++++++++++++++++   ~
+LL |     String::from(<str as AsRef<OsStr>>::as_ref("x"));
+   |                  ++++++++++++++++++++++++++++++   ~
 help: try using a fully qualified path to specify the expected types
    |
-LL |     String::from(path::<impl AsRef<Path> for str>::as_ref("x"));
-   |                  +++++++++++++++++++++++++++++++++++++++++   ~
+LL |     String::from(<str as AsRef<Path>>::as_ref("x"));
+   |                  +++++++++++++++++++++++++++++   ~
 help: try using a fully qualified path to specify the expected types
    |
 LL |     String::from(<str as AsRef<str>>::as_ref("x"));
    |                  ++++++++++++++++++++++++++++   ~
 help: try using a fully qualified path to specify the expected types
    |
-LL |     String::from(core::str::<impl AsRef<[u8]> for str>::as_ref("x"));
-   |                  ++++++++++++++++++++++++++++++++++++++++++++++   ~
+LL |     String::from(<str as AsRef<[u8]>>::as_ref("x"));
+   |                  +++++++++++++++++++++++++++++   ~
 
 error: aborting due to 17 previous errors
 

Original file line number	Diff line number	Diff line change
`@@ -227,7 +227,7 @@ pub trait Printer<'tcx>: Sized {`
`227`	`227`	`Some(trait_ref) => self.tcx().parent(trait_ref.def_id) == parent_def_id,`
`228`	`228`	`};`
`229`	`229`
`230`		`- if !in_self_mod && !in_trait_mod {`
	`230`	`+ if !in_self_mod && !in_trait_mod && !self.for_suggestion() {`
`231`	`231`	`// If the impl is not co-located with either self-type or`
`232`	`232`	`// trait-type, then fallback to a format that identifies`
`233`	`233`	`// the module more clearly.`
`@@ -243,6 +243,10 @@ pub trait Printer<'tcx>: Sized {`
`243`	`243`	`self.path_qualified(self_ty, impl_trait_ref)`
`244`	`244`	`}`
`245`	`245`	`}`
	`246`	`+`
	`247`	`+ fn for_suggestion(&self) -> bool {`
	`248`	`+ false`
	`249`	`+ }`
`246`	`250`	`}`
`247`	`251`
`248`	`252`	`/// As a heuristic, when we see an impl, if we see that the`
Original file line number	Diff line number	Diff line change
`@@ -2010,6 +2010,7 @@ pub struct FmtPrinterData<'a, 'tcx> {`
`2010`	`2010`
`2011`	`2011`	`pub ty_infer_name_resolver: Option<Box<dyn Fn(ty::TyVid) -> Option<Symbol> + 'a>>,`
`2012`	`2012`	`pub const_infer_name_resolver: Option<Box<dyn Fn(ty::ConstVid) -> Option<Symbol> + 'a>>,`
	`2013`	`+ pub for_suggestion: bool,`
`2013`	`2014`	`}`
`2014`	`2015`
`2015`	`2016`	`impl<'a, 'tcx> Deref for FmtPrinter<'a, 'tcx> {`
`@@ -2060,6 +2061,7 @@ impl<'a, 'tcx> FmtPrinter<'a, 'tcx> {`
`2060`	`2061`	`region_highlight_mode: RegionHighlightMode::default(),`
`2061`	`2062`	`ty_infer_name_resolver: None,`
`2062`	`2063`	`const_infer_name_resolver: None,`
	`2064`	`+ for_suggestion: false,`
`2063`	`2065`	`}))`
`2064`	`2066`	`}`
`2065`	`2067`
`@@ -2311,6 +2313,9 @@ impl<'tcx> Printer<'tcx> for FmtPrinter<'_, 'tcx> {`
`2311`	`2313`	`Ok(())`
`2312`	`2314`	`}`
`2313`	`2315`	`}`
	`2316`	`+ fn for_suggestion(&self) -> bool {`
	`2317`	`+ self.0.for_suggestion`
	`2318`	`+ }`
`2314`	`2319`	`}`
`2315`	`2320`
`2316`	`2321`	`impl<'tcx> PrettyPrinter<'tcx> for FmtPrinter<'_, 'tcx> {`
Original file line number	Diff line number	Diff line change
`@@ -205,6 +205,7 @@ fn fmt_printer<'a, 'tcx>(infcx: &'a InferCtxt<'tcx>, ns: Namespace) -> FmtPrinte`
`205`	`205`	`}`
`206`	`206`	`};`
`207`	`207`	`printer.ty_infer_name_resolver = Some(Box::new(ty_getter));`
	`208`	`+ printer.for_suggestion = true;`
`208`	`209`	`let const_getter =`
`209`	`210`	`move \|ct_vid\| Some(infcx.tcx.item_name(infcx.const_var_origin(ct_vid)?.param_def_id?));`
`210`	`211`	`printer.const_infer_name_resolver = Some(Box::new(const_getter));`