only set non-ADT derive error once per attribute, not per trait

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

diff --git a/src/libsyntax/ext/expand.rs b/src/libsyntax/ext/expand.rs
index ab0fd678e66f44b462b2a820a5e818fc97bf47ec..3a1b93425307e18715f77e9d0e88d28bec144a55 100644 (file)
--- a/src/libsyntax/ext/expand.rs
+++ b/src/libsyntax/ext/expand.rs
@@ -282,6 +282,24 @@ fn expand(&mut self, expansion: Expansion) -> Expansion {
                     let expansion = self.expand_invoc(invoc, ext);
                     self.collect_invocations(expansion, &[])
                 } else if let InvocationKind::Attr { attr: None, traits, item } = invoc.kind {
+                    let derive_allowed = match item {
+                        Annotatable::Item(ref item) => match item.node {
+                            ast::ItemKind::Struct(..) |
+                            ast::ItemKind::Enum(..) |
+                            ast::ItemKind::Union(..) => true,
+                            _ => false,
+                        },
+                        _ => false,
+                    };
+                    if !derive_allowed {
+                        let span = item.attrs().iter()
+                            .find(|attr| attr.check_name("derive"))
+                            .expect("`derive` attribute should exist").span;
+                        self.cx.span_err(span,
+                                         "`derive` may only be applied to structs, enums \
+                                          and unions");
+                    }
+
                     let item = item
                         .map_attrs(|mut attrs| { attrs.retain(|a| a.path != "derive"); attrs });
                     let item_with_markers =
@@ -384,7 +402,7 @@ fn expand_invoc(&mut self, invoc: Invocation, ext: Rc<SyntaxExtension>) -> Expan
         if self.cx.current_expansion.depth > self.cx.ecfg.recursion_limit {
             let info = self.cx.current_expansion.mark.expn_info().unwrap();
             let suggested_limit = self.cx.ecfg.recursion_limit * 2;
-            let mut err = self.cx.struct_span_fatal(info.call_site,
+            let mut err = self.cx.struct_span_err(info.call_site,
                 &format!("recursion limit reached while expanding the macro `{}`",
                          info.callee.name()));
             err.help(&format!(
@@ -608,7 +626,7 @@ fn expand_derive_invoc(&mut self, invoc: Invocation, ext: Rc<SyntaxExtension>) -
         match *ext {
             ProcMacroDerive(ref ext, _) => {
                 invoc.expansion_data.mark.set_expn_info(expn_info);
-                let span = Span { ctxt: self.cx.backtrace(), ..span };
+                let span = span.with_ctxt(self.cx.backtrace());
                 let dummy = ast::MetaItem { // FIXME(jseyfried) avoid this
                     name: keywords::Invalid.name(),
                     span: DUMMY_SP,
@@ -619,7 +637,7 @@ fn expand_derive_invoc(&mut self, invoc: Invocation, ext: Rc<SyntaxExtension>) -
             BuiltinDerive(func) => {
                 expn_info.callee.allow_internal_unstable = true;
                 invoc.expansion_data.mark.set_expn_info(expn_info);
-                let span = Span { ctxt: self.cx.backtrace(), ..span };
+                let span = span.with_ctxt(self.cx.backtrace());
                 let mut items = Vec::new();
                 func(self.cx, span, &attr.meta().unwrap(), &item, &mut |a| items.push(a));
                 kind.expect_from_annotatables(items)
@@ -640,6 +658,7 @@ fn parse_expansion(&mut self, toks: TokenStream, kind: ExpansionKind, path: &Pat
             Ok(expansion) => expansion,
             Err(mut err) => {
                 err.emit();
+                self.cx.trace_macros_diag();
                 return kind.dummy(span);
             }
         };
@@ -695,14 +714,13 @@ pub fn ensure_complete_parse(&mut self, macro_path: &Path, kind_name: &str, span
         if self.token != token::Eof {
             let msg = format!("macro expansion ignores token `{}` and any following",
                               self.this_token_to_string());
-            let mut def_site_span = self.span;
-            def_site_span.ctxt = SyntaxContext::empty(); // Avoid emitting backtrace info twice.
+            // 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();
-            self.cx.trace_macros_diag();
         }
     }
 }
@@ -1082,9 +1100,8 @@ fn fold_ident(&mut self, mut ident: Ident) -> Ident {
         ident
     }
 
-    fn new_span(&mut self, mut span: Span) -> Span {
-        span.ctxt = span.ctxt.apply_mark(self.0);
-        span
+    fn new_span(&mut self, span: Span) -> Span {
+        span.with_ctxt(span.ctxt().apply_mark(self.0))
     }
 
     fn fold_mac(&mut self, mac: ast::Mac) -> ast::Mac {