Rollup merge of #47613 - estebank:rustc_on_unimplemented, r=nikomatsakis

Add filtering options to `rustc_on_unimplemented`

- Add filtering options to `rustc_on_unimplemented` for local traits, filtering on `Self` and type arguments.
- Add a way to provide custom notes.
- Tweak binops text.
- Add filter to detect wether `Self` is local or belongs to another crate.
- Add filter to `Iterator` diagnostic for `&str`.

Partly addresses #44755 with a different syntax, as a first approach. Fixes #46216, fixes #37522, CC #34297, #46806.

1 files changed, 14 insertions, 17 deletions

diff --git a/src/libsyntax/parse/parser.rs b/src/libsyntax/parse/parser.rs
index 764b3d0a848..dc3745fc4a3 100644
--- a/src/libsyntax/parse/parser.rs
+++ b/src/libsyntax/parse/parser.rs
@@ -761,6 +761,18 @@ impl<'a> Parser<'a> {
         })
     }
 
+    fn expected_ident_found(&self) -> DiagnosticBuilder<'a> {
+        let mut err = self.struct_span_err(self.span,
+                                           &format!("expected identifier, found {}",
+                                                    self.this_token_descr()));
+        if let Some(token_descr) = self.token_descr() {
+            err.span_label(self.span, format!("expected identifier, found {}", token_descr));
+        } else {
+            err.span_label(self.span, "expected identifier");
+        }
+        err
+    }
+
     pub fn parse_ident(&mut self) -> PResult<'a, ast::Ident> {
         self.parse_ident_common(true)
     }
@@ -769,15 +781,7 @@ impl<'a> Parser<'a> {
         match self.token {
             token::Ident(i) => {
                 if self.token.is_reserved_ident() {
-                    let mut err = self.struct_span_err(self.span,
-                                                       &format!("expected identifier, found {}",
-                                                                self.this_token_descr()));
-                    if let Some(token_descr) = self.token_descr() {
-                        err.span_label(self.span, format!("expected identifier, found {}",
-                                                          token_descr));
-                    } else {
-                        err.span_label(self.span, "expected identifier");
-                    }
+                    let mut err = self.expected_ident_found();
                     if recover {
                         err.emit();
                     } else {
@@ -791,14 +795,7 @@ impl<'a> Parser<'a> {
                 Err(if self.prev_token_kind == PrevTokenKind::DocComment {
                         self.span_fatal_err(self.prev_span, Error::UselessDocComment)
                     } else {
-                        let mut err = self.fatal(&format!("expected identifier, found `{}`",
-                                                          self.this_token_to_string()));
-                        if let Some(token_descr) = self.token_descr() {
-                            err.span_label(self.span, format!("expected identifier, found {}",
-                                                              token_descr));
-                        } else {
-                            err.span_label(self.span, "expected identifier");
-                        }
+                        let mut err = self.expected_ident_found();
                         if self.token == token::Underscore {
                             err.note("`_` is a wildcard pattern, not an identifier");
                         }