Do not abort compilation if expansion produces errors

Fix a number of uncovered deficiencies in diagnostics

2 files changed, 11 insertions, 14 deletions

diff --git a/src/libsyntax/ext/base.rs b/src/libsyntax/ext/base.rs
index d576397c942..84aa57d7d86 100644
--- a/src/libsyntax/ext/base.rs
+++ b/src/libsyntax/ext/base.rs
@@ -2,7 +2,7 @@ pub use self::SyntaxExtension::*;
 
 use ast::{self, Attribute, Name, PatKind, MetaItem};
 use attr::HasAttrs;
-use source_map::{self, SourceMap, Spanned, respan};
+use source_map::{SourceMap, Spanned, respan};
 use syntax_pos::{Span, MultiSpan, DUMMY_SP};
 use edition::Edition;
 use errors::{DiagnosticBuilder, DiagnosticId};
@@ -481,7 +481,7 @@ impl DummyResult {
     pub fn raw_expr(sp: Span) -> P<ast::Expr> {
         P(ast::Expr {
             id: ast::DUMMY_NODE_ID,
-            node: ast::ExprKind::Lit(source_map::respan(sp, ast::LitKind::Bool(false))),
+            node: ast::ExprKind::Err,
             span: sp,
             attrs: ThinVec::new(),
         })
@@ -496,10 +496,11 @@ impl DummyResult {
         }
     }
 
+    /// A plain dummy type.
     pub fn raw_ty(sp: Span) -> P<ast::Ty> {
         P(ast::Ty {
             id: ast::DUMMY_NODE_ID,
-            node: ast::TyKind::Infer,
+            node: ast::TyKind::Err,
             span: sp
         })
     }
@@ -796,7 +797,6 @@ pub struct ExtCtxt<'a> {
     pub ecfg: expand::ExpansionConfig<'a>,
     pub root_path: PathBuf,
     pub resolver: &'a mut dyn Resolver,
-    pub resolve_err_count: usize,
     pub current_expansion: ExpansionData,
     pub expansions: FxHashMap<Span, Vec<String>>,
 }
@@ -811,7 +811,6 @@ impl<'a> ExtCtxt<'a> {
             ecfg,
             root_path: PathBuf::new(),
             resolver,
-            resolve_err_count: 0,
             current_expansion: ExpansionData {
                 mark: Mark::root(),
                 depth: 0,
diff --git a/src/libsyntax/ext/expand.rs b/src/libsyntax/ext/expand.rs
index 55012bb7f5a..f8f1e830770 100644
--- a/src/libsyntax/ext/expand.rs
+++ b/src/libsyntax/ext/expand.rs
@@ -344,8 +344,10 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
             // FIXME(jseyfried): Refactor out the following logic
             let (expanded_fragment, new_invocations) = if let Some(ext) = ext {
                 if let Some(ext) = ext {
-                    let dummy = invoc.fragment_kind.dummy(invoc.span()).unwrap();
-                    let fragment = self.expand_invoc(invoc, &*ext).unwrap_or(dummy);
+                    let (invoc_fragment_kind, invoc_span) = (invoc.fragment_kind, invoc.span());
+                    let fragment = self.expand_invoc(invoc, &*ext).unwrap_or_else(|| {
+                        invoc_fragment_kind.dummy(invoc_span).unwrap()
+                    });
                     self.collect_invocations(fragment, &[])
                 } else if let InvocationKind::Attr { attr: None, traits, item, .. } = invoc.kind {
                     if !item.derive_allowed() {
@@ -431,9 +433,7 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
 
     fn resolve_imports(&mut self) {
         if self.monotonic {
-            let err_count = self.cx.parse_sess.span_diagnostic.err_count();
             self.cx.resolver.resolve_imports();
-            self.cx.resolve_err_count += self.cx.parse_sess.span_diagnostic.err_count() - err_count;
         }
     }
 
@@ -457,11 +457,9 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
         };
 
         if self.monotonic {
-            let err_count = self.cx.parse_sess.span_diagnostic.err_count();
-            let mark = self.cx.current_expansion.mark;
-            self.cx.resolver.visit_ast_fragment_with_placeholders(mark, &fragment_with_placeholders,
-                                                                  derives);
-            self.cx.resolve_err_count += self.cx.parse_sess.span_diagnostic.err_count() - err_count;
+            self.cx.resolver.visit_ast_fragment_with_placeholders(
+                self.cx.current_expansion.mark, &fragment_with_placeholders, derives
+            );
         }
 
         (fragment_with_placeholders, invocations)