Provide specific label for patern parsing error

[rust.git] / src / libsyntax / ext / expand.rs

diff --git a/src/libsyntax/ext/expand.rs b/src/libsyntax/ext/expand.rs
index 9e06384f5a804e574124136419bba662902f37ac..84e40a7e4033de5dc305436460d8fc29e4d23544 100644 (file)
--- a/src/libsyntax/ext/expand.rs
+++ b/src/libsyntax/ext/expand.rs
@@ -764,7 +764,7 @@ fn expand_bang_invoc(&mut self,
                                                                     edition) {
                     dummy_span
                 } else {
-                    kind.make_from(expander.expand(self.cx, span, mac.node.stream()))
+                    kind.make_from(expander.expand(self.cx, span, mac.node.stream(), None))
                 }
             }
 
@@ -785,7 +785,12 @@ fn expand_bang_invoc(&mut self,
                                                                     edition) {
                     dummy_span
                 } else {
-                    kind.make_from(expander.expand(self.cx, span, mac.node.stream()))
+                    kind.make_from(expander.expand(
+                        self.cx,
+                        span,
+                        mac.node.stream(),
+                        def_info.map(|(_, s)| s),
+                    ))
                 }
             }
 
@@ -1025,7 +1030,7 @@ pub fn parse_ast_fragment(&mut self, kind: AstFragmentKind, macro_legacy_warning
                 }
             },
             AstFragmentKind::Ty => AstFragment::Ty(self.parse_ty()?),
-            AstFragmentKind::Pat => AstFragment::Pat(self.parse_pat()?),
+            AstFragmentKind::Pat => AstFragment::Pat(self.parse_pat(None)?),
         })
     }
 
@@ -1036,10 +1041,28 @@ pub fn ensure_complete_parse(&mut self, macro_path: &Path, kind_name: &str, span
             // Avoid emitting backtrace info twice.
             let def_site_span = self.span.with_ctxt(SyntaxContext::empty());
             let mut err = self.diagnostic().struct_span_err(def_site_span, &msg);
-            let msg = format!("caused by the macro expansion here; the usage \
-                               of `{}!` is likely invalid in {} context",
-                               macro_path, kind_name);
-            err.span_note(span, &msg).emit();
+            err.span_label(span, "caused by the macro expansion here");
+            let msg = format!(
+                "the usage of `{}!` is likely invalid in {} context",
+                macro_path,
+                kind_name,
+            );
+            err.note(&msg);
+            let semi_span = self.sess.source_map().next_point(span);
+
+            let semi_full_span = semi_span.to(self.sess.source_map().next_point(semi_span));
+            match self.sess.source_map().span_to_snippet(semi_full_span) {
+                Ok(ref snippet) if &snippet[..] != ";" && kind_name == "expression" => {
+                    err.span_suggestion_with_applicability(
+                        semi_span,
+                        "you might be missing a semicolon here",
+                        ";".to_owned(),
+                        Applicability::MaybeIncorrect,
+                    );
+                }
+                _ => {}
+            }
+            err.emit();
         }
     }
 }