3 files changed, 28 insertions, 7 deletions
diff --git a/compiler/rustc_expand/src/expand.rs b/compiler/rustc_expand/src/expand.rs
index 3629e668fa9..09beda33483 100644
--- a/compiler/rustc_expand/src/expand.rs
+++ b/compiler/rustc_expand/src/expand.rs
@@ -559,7 +559,7 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
         self.cx.force_mode = orig_force_mode;
 
         // Finally incorporate all the expanded macros into the input AST fragment.
-        let mut placeholder_expander = PlaceholderExpander::default();
+        let mut placeholder_expander = PlaceholderExpander::new(self.cx, self.monotonic);
         while let Some(expanded_fragments) = expanded_fragments.pop() {
             for (expn_id, expanded_fragment) in expanded_fragments.into_iter().rev() {
                 placeholder_expander
@@ -1341,9 +1341,14 @@ impl<'a, 'b> MutVisitor for InvocationCollector<'a, 'b> {
             }
         }
 
+        // The placeholder expander gives ids to statements, so we avoid folding the id here.
         // We don't use `assign_id!` - it will be called when we visit statement's contents
         // (e.g. an expression, item, or local)
-        let res = noop_flat_map_stmt(stmt, self);
+        let ast::Stmt { id, kind, span } = stmt;
+        let res = noop_flat_map_stmt_kind(kind, self)
+            .into_iter()
+            .map(|kind| ast::Stmt { id, kind, span })
+            .collect();
 
         self.cx.current_expansion.is_trailing_mac = false;
         res
diff --git a/compiler/rustc_expand/src/lib.rs b/compiler/rustc_expand/src/lib.rs
index 43287984050..efed41de23a 100644
--- a/compiler/rustc_expand/src/lib.rs
+++ b/compiler/rustc_expand/src/lib.rs
@@ -7,7 +7,6 @@
 #![feature(proc_macro_internals)]
 #![feature(proc_macro_span)]
 #![feature(try_blocks)]
-#![recursion_limit = "256"]
 
 #[macro_use]
 extern crate rustc_macros;
diff --git a/compiler/rustc_expand/src/placeholders.rs b/compiler/rustc_expand/src/placeholders.rs
index 8e78fcbb8db..6586ba138fb 100644
--- a/compiler/rustc_expand/src/placeholders.rs
+++ b/compiler/rustc_expand/src/placeholders.rs
@@ -1,3 +1,4 @@
+use crate::base::ExtCtxt;
 use crate::expand::{AstFragment, AstFragmentKind};
 
 use rustc_ast as ast;
@@ -174,12 +175,17 @@ pub fn placeholder(
     }
 }
 
-#[derive(Default)]
-pub struct PlaceholderExpander {
+pub struct PlaceholderExpander<'a, 'b> {
     expanded_fragments: FxHashMap<ast::NodeId, AstFragment>,
+    cx: &'a mut ExtCtxt<'b>,
+    monotonic: bool,
 }
 
-impl PlaceholderExpander {
+impl<'a, 'b> PlaceholderExpander<'a, 'b> {
+    pub fn new(cx: &'a mut ExtCtxt<'b>, monotonic: bool) -> Self {
+        PlaceholderExpander { cx, expanded_fragments: FxHashMap::default(), monotonic }
+    }
+
     pub fn add(&mut self, id: ast::NodeId, mut fragment: AstFragment) {
         fragment.mut_visit_with(self);
         self.expanded_fragments.insert(id, fragment);
@@ -190,7 +196,7 @@ impl PlaceholderExpander {
     }
 }
 
-impl MutVisitor for PlaceholderExpander {
+impl<'a, 'b> MutVisitor for PlaceholderExpander<'a, 'b> {
     fn flat_map_arm(&mut self, arm: ast::Arm) -> SmallVec<[ast::Arm; 1]> {
         if arm.is_placeholder {
             self.remove(arm.id).make_arms()
@@ -354,4 +360,15 @@ impl MutVisitor for PlaceholderExpander {
             _ => noop_visit_ty(ty, self),
         }
     }
+
+    fn visit_block(&mut self, block: &mut P<ast::Block>) {
+        noop_visit_block(block, self);
+
+        for stmt in block.stmts.iter_mut() {
+            if self.monotonic {
+                assert_eq!(stmt.id, ast::DUMMY_NODE_ID);
+                stmt.id = self.cx.resolver.next_node_id();
+            }
+        }
+    }
 }