Add delay_span_bug to AttrWrapper::take_for_recovery

Author: WaffleLapkin

Diff for: compiler/rustc_parse/src/parser/attr_wrapper.rs

@@ -5,7 +5,8 @@ use rustc_ast::tokenstream::{AttrTokenTree, DelimSpan, LazyAttrTokenStream, Spac
 use rustc_ast::{self as ast};
 use rustc_ast::{AttrVec, Attribute, HasAttrs, HasTokens};
 use rustc_errors::PResult;
-use rustc_span::{sym, Span};
+use rustc_session::parse::ParseSess;
+use rustc_span::{sym, Span, DUMMY_SP};
 
 use std::convert::TryInto;
 use std::ops::Range;
@@ -39,8 +40,13 @@ impl AttrWrapper {
     pub fn empty() -> AttrWrapper {
         AttrWrapper { attrs: AttrVec::new(), start_pos: usize::MAX }
     }
-    // FIXME: Delay span bug here?
-    pub(crate) fn take_for_recovery(self) -> AttrVec {
+
+    pub(crate) fn take_for_recovery(self, sess: &ParseSess) -> AttrVec {
+        sess.span_diagnostic.delay_span_bug(
+            self.attrs.get(0).map(|attr| attr.span).unwrap_or(DUMMY_SP),
+            "AttrVec is taken for recovery but no error is produced",
+        );
+
         self.attrs
     }
 

Diff for: compiler/rustc_parse/src/parser/expr.rs

@@ -2272,7 +2272,7 @@ impl<'a> Parser<'a> {
                 self.mk_block_err(cond_span.shrink_to_hi())
             }
         } else {
-            let attrs = self.parse_outer_attributes()?.take_for_recovery(); // For recovery.
+            let attrs = self.parse_outer_attributes()?; // For recovery.
             let block = if self.check(&token::OpenDelim(Delimiter::Brace)) {
                 self.parse_block()?
             } else {
@@ -2289,7 +2289,7 @@ impl<'a> Parser<'a> {
                     })?
                 }
             };
-            self.error_on_if_block_attrs(lo, false, block.span, &attrs);
+            self.error_on_if_block_attrs(lo, false, block.span, attrs);
             block
         };
         let els = if self.eat_keyword(kw::Else) { Some(self.parse_else_expr()?) } else { None };
@@ -2350,7 +2350,7 @@ impl<'a> Parser<'a> {
     /// Parses an `else { ... }` expression (`else` token already eaten).
     fn parse_else_expr(&mut self) -> PResult<'a, P<Expr>> {
         let else_span = self.prev_token.span; // `else`
-        let attrs = self.parse_outer_attributes()?.take_for_recovery(); // For recovery.
+        let attrs = self.parse_outer_attributes()?; // For recovery.
         let expr = if self.eat_keyword(kw::If) {
             self.parse_if_expr()?
         } else if self.check(&TokenKind::OpenDelim(Delimiter::Brace)) {
@@ -2385,7 +2385,7 @@ impl<'a> Parser<'a> {
                 },
             }
         };
-        self.error_on_if_block_attrs(else_span, true, expr.span, &attrs);
+        self.error_on_if_block_attrs(else_span, true, expr.span, attrs);
         Ok(expr)
     }
 
@@ -2394,8 +2394,13 @@ impl<'a> Parser<'a> {
         ctx_span: Span,
         is_ctx_else: bool,
         branch_span: Span,
-        attrs: &[ast::Attribute],
+        attrs: AttrWrapper,
     ) {
+        if attrs.is_empty() {
+            return;
+        }
+
+        let attrs: &[ast::Attribute] = &attrs.take_for_recovery(self.sess);
         let (attributes, last) = match attrs {
             [] => return,
             [x0 @ xn] | [x0, .., xn] => (x0.span.to(xn.span), xn.span),

Diff for: compiler/rustc_parse/src/parser/stmt.rs

@@ -19,7 +19,7 @@ use rustc_ast as ast;
 use rustc_ast::ptr::P;
 use rustc_ast::token::{self, Delimiter, TokenKind};
 use rustc_ast::util::classify;
-use rustc_ast::{AttrStyle, AttrVec, Attribute, LocalKind, MacCall, MacCallStmt, MacStmtStyle};
+use rustc_ast::{AttrStyle, AttrVec, LocalKind, MacCall, MacCallStmt, MacStmtStyle};
 use rustc_ast::{Block, BlockCheckMode, Expr, ExprKind, HasAttrs, Local, Stmt};
 use rustc_ast::{StmtKind, DUMMY_NODE_ID};
 use rustc_errors::{Applicability, DiagnosticBuilder, ErrorGuaranteed, PResult};
@@ -101,7 +101,7 @@ impl<'a> Parser<'a> {
             self.mk_stmt(lo.to(item.span), StmtKind::Item(P(item)))
         } else if self.eat(&token::Semi) {
             // Do not attempt to parse an expression if we're done here.
-            self.error_outer_attrs(&attrs.take_for_recovery());
+            self.error_outer_attrs(attrs);
             self.mk_stmt(lo, StmtKind::Empty)
         } else if self.token != token::CloseDelim(Delimiter::Brace) {
             // Remainder are line-expr stmts.
@@ -120,7 +120,7 @@ impl<'a> Parser<'a> {
             }
             self.mk_stmt(lo.to(e.span), StmtKind::Expr(e))
         } else {
-            self.error_outer_attrs(&attrs.take_for_recovery());
+            self.error_outer_attrs(attrs);
             return Ok(None);
         }))
     }
@@ -199,8 +199,10 @@ impl<'a> Parser<'a> {
 
     /// Error on outer attributes in this context.
     /// Also error if the previous token was a doc comment.
-    fn error_outer_attrs(&self, attrs: &[Attribute]) {
-        if let [.., last] = attrs {
+    fn error_outer_attrs(&self, attrs: AttrWrapper) {
+        if !attrs.is_empty()
+        && let attrs = attrs.take_for_recovery(self.sess)
+        && let attrs @ [.., last] = &*attrs {
             if last.is_doc_comment() {
                 self.sess.emit_err(DocCommentDoesNotDocumentAnything {
                     span: last.span,