syntax: revert `ast::AsyncArgument` and associated changes.

Here follows the main reverts applied in order to make this commit:

Revert "Rollup merge of #60676 - davidtwco:issue-60674, r=cramertj"

This reverts commit 45b09453dbf120cc23d889435aac3ed7d2ec8eb7, reversing
changes made to f6df1f6c30b469cb9e65c5453a0efa03cbb6005e.

Revert "Rollup merge of #60437 - davidtwco:issue-60236, r=nikomatsakis"

This reverts commit 16939a50ea440e72cb6ecefdaabb988addb1ec0e, reversing
changes made to 12bf98155249783583a91863c5dccf9e346f1226.

Revert "Rollup merge of #59823 - davidtwco:issue-54716, r=cramertj"

This reverts commit 62d1574876f5531bce1b267e62dff520d7adcbbb, reversing
changes made to 4eff8526a789e0dfa8b97f7dec91b7b5c18e8544.

2 files changed, 4 insertions, 25 deletions

diff --git a/src/libsyntax/ext/build.rs b/src/libsyntax/ext/build.rs
index 9c0ffc1f6e8..47c79f8466a 100644
--- a/src/libsyntax/ext/build.rs
+++ b/src/libsyntax/ext/build.rs
@@ -516,7 +516,6 @@ impl<'a> AstBuilder for ExtCtxt<'a> {
             id: ast::DUMMY_NODE_ID,
             span: sp,
             attrs: ThinVec::new(),
-            source: ast::LocalSource::Normal,
         });
         ast::Stmt {
             id: ast::DUMMY_NODE_ID,
@@ -545,7 +544,6 @@ impl<'a> AstBuilder for ExtCtxt<'a> {
             id: ast::DUMMY_NODE_ID,
             span: sp,
             attrs: ThinVec::new(),
-            source: ast::LocalSource::Normal,
         });
         ast::Stmt {
             id: ast::DUMMY_NODE_ID,
@@ -563,7 +561,6 @@ impl<'a> AstBuilder for ExtCtxt<'a> {
             id: ast::DUMMY_NODE_ID,
             span,
             attrs: ThinVec::new(),
-            source: ast::LocalSource::Normal,
         });
         ast::Stmt {
             id: ast::DUMMY_NODE_ID,
@@ -971,8 +968,7 @@ impl<'a> AstBuilder for ExtCtxt<'a> {
         ast::Arg {
             ty,
             pat: arg_pat,
-            id: ast::DUMMY_NODE_ID,
-            source: ast::ArgSource::Normal,
+            id: ast::DUMMY_NODE_ID
         }
     }
 
diff --git a/src/libsyntax/ext/placeholders.rs b/src/libsyntax/ext/placeholders.rs
index 8f24d11cfd5..c56c156182b 100644
--- a/src/libsyntax/ext/placeholders.rs
+++ b/src/libsyntax/ext/placeholders.rs
@@ -101,13 +101,6 @@ impl<'a, 'b> PlaceholderExpander<'a, 'b> {
     fn remove(&mut self, id: ast::NodeId) -> AstFragment {
         self.expanded_fragments.remove(&id).unwrap()
     }
-
-    fn next_id(&mut self, id: &mut ast::NodeId) {
-        if self.monotonic {
-            assert_eq!(*id, ast::DUMMY_NODE_ID);
-            *id = self.cx.resolver.next_node_id()
-        }
-    }
 }
 
 impl<'a, 'b> MutVisitor for PlaceholderExpander<'a, 'b> {
@@ -189,19 +182,9 @@ impl<'a, 'b> MutVisitor for PlaceholderExpander<'a, 'b> {
         noop_visit_block(block, self);
 
         for stmt in block.stmts.iter_mut() {
-            self.next_id(&mut stmt.id);
-        }
-    }
-
-    fn visit_asyncness(&mut self, a: &mut ast::IsAsync) {
-        noop_visit_asyncness(a, self);
-
-        if let ast::IsAsync::Async { ref mut arguments, .. } = a {
-            for argument in arguments.iter_mut() {
-                self.next_id(&mut argument.move_stmt.id);
-                if let Some(ref mut pat_stmt) = &mut argument.pat_stmt {
-                    self.next_id(&mut pat_stmt.id);
-                }
+            if self.monotonic {
+                assert_eq!(stmt.id, ast::DUMMY_NODE_ID);
+                stmt.id = self.cx.resolver.next_node_id();
             }
         }
     }