defatalize AttrProcMacro::expand

Author: Centril

src/librustc_expand/base.rs

@@ -325,7 +325,7 @@ pub trait AttrProcMacro {
         span: Span,
         annotation: TokenStream,
         annotated: TokenStream,
-    ) -> TokenStream;
+    ) -> Result<TokenStream, ErrorReported>;
 }
 
 impl<F> AttrProcMacro for F
@@ -338,9 +338,9 @@ where
         _span: Span,
         annotation: TokenStream,
         annotated: TokenStream,
-    ) -> TokenStream {
+    ) -> Result<TokenStream, ErrorReported> {
         // FIXME setup implicit context in TLS before calling self.
-        (*self)(annotation, annotated)
+        Ok((*self)(annotation, annotated))
     }
 }
 

src/librustc_expand/expand.rs

@@ -704,8 +704,11 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
                     if let MacArgs::Eq(..) = attr_item.args {
                         self.cx.span_err(span, "key-value macro attributes are not supported");
                     }
-                    let tok_result =
-                        expander.expand(self.cx, span, attr_item.args.inner_tokens(), tokens);
+                    let inner_tokens = attr_item.args.inner_tokens();
+                    let tok_result = match expander.expand(self.cx, span, inner_tokens, tokens) {
+                        Err(_) => return ExpandResult::Ready(fragment_kind.dummy(span)),
+                        Ok(ts) => ts,
+                    };
                     self.parse_ast_fragment(tok_result, fragment_kind, &attr_item.path, span)
                 }
                 SyntaxExtensionKind::LegacyAttr(expander) => {

src/librustc_expand/proc_macro.rs

@@ -45,21 +45,16 @@ impl base::AttrProcMacro for AttrProcMacro {
         span: Span,
         annotation: TokenStream,
         annotated: TokenStream,
-    ) -> TokenStream {
+    ) -> Result<TokenStream, ErrorReported> {
         let server = proc_macro_server::Rustc::new(ecx);
-        match self.client.run(&EXEC_STRATEGY, server, annotation, annotated) {
-            Ok(stream) => stream,
-            Err(e) => {
-                let msg = "custom attribute panicked";
-                let mut err = ecx.struct_span_fatal(span, msg);
-                if let Some(s) = e.as_str() {
-                    err.help(&format!("message: {}", s));
-                }
-
-                err.emit();
-                FatalError.raise();
+        self.client.run(&EXEC_STRATEGY, server, annotation, annotated).map_err(|e| {
+            let mut err = ecx.struct_span_err(span, "custom attribute panicked");
+            if let Some(s) = e.as_str() {
+                err.help(&format!("message: {}", s));
             }
-        }
+            err.emit();
+            ErrorReported
+        })
     }
 }