From 0d29142aad9554a23f0881be95110ad96365bfcf Mon Sep 17 00:00:00 2001
From: Vadim Petrochenkov <vadim.petrochenkov@gmail.com>
Date: Wed, 14 Aug 2019 01:59:14 +0300
Subject: [PATCH 1/2] expand: `expand_fragment` -> `fully_expand_fragment`
---
src/libsyntax/ext/expand.rs | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)
diff --git a/src/libsyntax/ext/expand.rs b/src/libsyntax/ext/expand.rs
index 9a3195b1165b1..21cf232ecc34a 100644
--- a/src/libsyntax/ext/expand.rs
+++ b/src/libsyntax/ext/expand.rs
@@ -118,13 +118,13 @@ macro_rules! ast_fragments {
impl<'a, 'b> MutVisitor for MacroExpander<'a, 'b> {
fn filter_map_expr(&mut self, expr: P<ast::Expr>) -> Option<P<ast::Expr>> {
- self.expand_fragment(AstFragment::OptExpr(Some(expr))).make_opt_expr()
+ self.fully_expand_fragment(AstFragment::OptExpr(Some(expr))).make_opt_expr()
}
$($(fn $mut_visit_ast(&mut self, ast: &mut $AstTy) {
- visit_clobber(ast, |ast| self.expand_fragment(AstFragment::$Kind(ast)).$make_ast());
+ visit_clobber(ast, |ast| self.fully_expand_fragment(AstFragment::$Kind(ast)).$make_ast());
})?)*
$($(fn $flat_map_ast_elt(&mut self, ast_elt: <$AstTy as IntoIterator>::Item) -> $AstTy {
- self.expand_fragment(AstFragment::$Kind(smallvec![ast_elt])).$make_ast()
+ self.fully_expand_fragment(AstFragment::$Kind(smallvec![ast_elt])).$make_ast()
})?)*
}
@@ -265,7 +265,7 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
tokens: None,
})]);
- match self.expand_fragment(krate_item).make_items().pop().map(P::into_inner) {
+ match self.fully_expand_fragment(krate_item).make_items().pop().map(P::into_inner) {
Some(ast::Item { attrs, node: ast::ItemKind::Mod(module), .. }) => {
krate.attrs = attrs;
krate.module = module;
@@ -285,8 +285,8 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
krate
}
- // Fully expand all macro invocations in this AST fragment.
- fn expand_fragment(&mut self, input_fragment: AstFragment) -> AstFragment {
+ // Recursively expand all macro invocations in this AST fragment.
+ fn fully_expand_fragment(&mut self, input_fragment: AstFragment) -> AstFragment {
let orig_expansion_data = self.cx.current_expansion.clone();
self.cx.current_expansion.depth = 0;
From d416ebeb6ee265c980778df9bc4d84dc4a7b8580 Mon Sep 17 00:00:00 2001
From: Vadim Petrochenkov <vadim.petrochenkov@gmail.com>
Date: Wed, 14 Aug 2019 02:30:09 +0300
Subject: [PATCH 2/2] expand: Unimplement `MutVisitor` on `MacroExpander`
Each call to `fully_expand_fragment` is something unique, interesting, and requiring attention.
It represents a "root" of expansion and its use means that something unusual is happening, like eager expansion or expansion performed outside of the primary expansion pass.
So, it shouldn't be hide under a generic visitor call.
Also, from all the implemented visitor methods only two were actually used.
---
src/libsyntax/ext/base.rs | 14 +++++++++----
src/libsyntax/ext/expand.rs | 14 +------------
src/libsyntax_ext/proc_macro_harness.rs | 9 +++++----
src/libsyntax_ext/test_harness.rs | 27 ++++++++++++++-----------
4 files changed, 31 insertions(+), 33 deletions(-)
diff --git a/src/libsyntax/ext/base.rs b/src/libsyntax/ext/base.rs
index 7f4feff6be670..532de05eea214 100644
--- a/src/libsyntax/ext/base.rs
+++ b/src/libsyntax/ext/base.rs
@@ -947,8 +947,10 @@ pub fn expr_to_spanned_string<'a>(
// Update `expr.span`'s ctxt now in case expr is an `include!` macro invocation.
expr.span = expr.span.apply_mark(cx.current_expansion.id);
- // we want to be able to handle e.g., `concat!("foo", "bar")`
- cx.expander().visit_expr(&mut expr);
+ // Perform eager expansion on the expression.
+ // We want to be able to handle e.g., `concat!("foo", "bar")`.
+ let expr = cx.expander().fully_expand_fragment(AstFragment::Expr(expr)).make_expr();
+
Err(match expr.node {
ast::ExprKind::Lit(ref l) => match l.node {
ast::LitKind::Str(s, style) => return Ok(respan(expr.span, (s, style))),
@@ -1013,8 +1015,12 @@ pub fn get_exprs_from_tts(cx: &mut ExtCtxt<'_>,
let mut p = cx.new_parser_from_tts(tts);
let mut es = Vec::new();
while p.token != token::Eof {
- let mut expr = panictry!(p.parse_expr());
- cx.expander().visit_expr(&mut expr);
+ let expr = panictry!(p.parse_expr());
+
+ // Perform eager expansion on the expression.
+ // We want to be able to handle e.g., `concat!("foo", "bar")`.
+ let expr = cx.expander().fully_expand_fragment(AstFragment::Expr(expr)).make_expr();
+
es.push(expr);
if p.eat(&token::Comma) {
continue;
diff --git a/src/libsyntax/ext/expand.rs b/src/libsyntax/ext/expand.rs
index 21cf232ecc34a..402b42dfbc80d 100644
--- a/src/libsyntax/ext/expand.rs
+++ b/src/libsyntax/ext/expand.rs
@@ -116,18 +116,6 @@ macro_rules! ast_fragments {
}
}
- impl<'a, 'b> MutVisitor for MacroExpander<'a, 'b> {
- fn filter_map_expr(&mut self, expr: P<ast::Expr>) -> Option<P<ast::Expr>> {
- self.fully_expand_fragment(AstFragment::OptExpr(Some(expr))).make_opt_expr()
- }
- $($(fn $mut_visit_ast(&mut self, ast: &mut $AstTy) {
- visit_clobber(ast, |ast| self.fully_expand_fragment(AstFragment::$Kind(ast)).$make_ast());
- })?)*
- $($(fn $flat_map_ast_elt(&mut self, ast_elt: <$AstTy as IntoIterator>::Item) -> $AstTy {
- self.fully_expand_fragment(AstFragment::$Kind(smallvec![ast_elt])).$make_ast()
- })?)*
- }
-
impl<'a> MacResult for crate::ext::tt::macro_rules::ParserAnyMacro<'a> {
$(fn $make_ast(self: Box<crate::ext::tt::macro_rules::ParserAnyMacro<'a>>)
-> Option<$AstTy> {
@@ -286,7 +274,7 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
}
// Recursively expand all macro invocations in this AST fragment.
- fn fully_expand_fragment(&mut self, input_fragment: AstFragment) -> AstFragment {
+ pub fn fully_expand_fragment(&mut self, input_fragment: AstFragment) -> AstFragment {
let orig_expansion_data = self.cx.current_expansion.clone();
self.cx.current_expansion.depth = 0;
diff --git a/src/libsyntax_ext/proc_macro_harness.rs b/src/libsyntax_ext/proc_macro_harness.rs
index 7913a7442edc7..70325539f301f 100644
--- a/src/libsyntax_ext/proc_macro_harness.rs
+++ b/src/libsyntax_ext/proc_macro_harness.rs
@@ -1,18 +1,17 @@
use std::mem;
+use smallvec::smallvec;
use syntax::ast::{self, Ident};
use syntax::attr;
use syntax::source_map::{ExpnInfo, ExpnKind, respan};
use syntax::ext::base::{ExtCtxt, MacroKind};
-use syntax::ext::expand::ExpansionConfig;
+use syntax::ext::expand::{AstFragment, ExpansionConfig};
use syntax::ext::hygiene::ExpnId;
use syntax::ext::proc_macro::is_proc_macro_attr;
-use syntax::mut_visit::MutVisitor;
use syntax::parse::ParseSess;
use syntax::ptr::P;
use syntax::symbol::{kw, sym};
use syntax::visit::{self, Visitor};
-
use syntax_pos::{Span, DUMMY_SP};
struct ProcMacroDerive {
@@ -409,5 +408,7 @@ fn mk_decls(
i
});
- cx.monotonic_expander().flat_map_item(module).pop().unwrap()
+ // Integrate the new module into existing module structures.
+ let module = AstFragment::Items(smallvec![module]);
+ cx.monotonic_expander().fully_expand_fragment(module).make_items().pop().unwrap()
}
diff --git a/src/libsyntax_ext/test_harness.rs b/src/libsyntax_ext/test_harness.rs
index eec8a3f802343..0267637e54062 100644
--- a/src/libsyntax_ext/test_harness.rs
+++ b/src/libsyntax_ext/test_harness.rs
@@ -6,7 +6,7 @@ use syntax::ast::{self, Ident};
use syntax::attr;
use syntax::entry::{self, EntryPointType};
use syntax::ext::base::{ExtCtxt, Resolver};
-use syntax::ext::expand::ExpansionConfig;
+use syntax::ext::expand::{AstFragment, ExpansionConfig};
use syntax::ext::hygiene::{ExpnId, MacroKind};
use syntax::feature_gate::Features;
use syntax::mut_visit::{*, ExpectOne};
@@ -74,12 +74,7 @@ impl<'a> MutVisitor for TestHarnessGenerator<'a> {
noop_visit_crate(c, self);
// Create a main function to run our tests
- let test_main = {
- let unresolved = mk_main(&mut self.cx);
- self.cx.ext_cx.monotonic_expander().flat_map_item(unresolved).pop().unwrap()
- };
-
- c.module.items.push(test_main);
+ c.module.items.push(mk_main(&mut self.cx));
}
fn flat_map_item(&mut self, i: P<ast::Item>) -> SmallVec<[P<ast::Item>; 1]> {
@@ -216,7 +211,7 @@ fn mk_reexport_mod(cx: &mut TestCtxt<'_>,
let name = Ident::from_str("__test_reexports").gensym();
let parent = if parent == ast::DUMMY_NODE_ID { ast::CRATE_NODE_ID } else { parent };
cx.ext_cx.current_expansion.id = cx.ext_cx.resolver.get_module_scope(parent);
- let it = cx.ext_cx.monotonic_expander().flat_map_item(P(ast::Item {
+ let module = P(ast::Item {
ident: name,
attrs: Vec::new(),
id: ast::DUMMY_NODE_ID,
@@ -224,9 +219,14 @@ fn mk_reexport_mod(cx: &mut TestCtxt<'_>,
vis: dummy_spanned(ast::VisibilityKind::Public),
span: DUMMY_SP,
tokens: None,
- })).pop().unwrap();
+ });
- (it, name)
+ // Integrate the new module into existing module structures.
+ let module = AstFragment::Items(smallvec![module]);
+ let module =
+ cx.ext_cx.monotonic_expander().fully_expand_fragment(module).make_items().pop().unwrap();
+
+ (module, name)
}
/// Crawl over the crate, inserting test reexports and the test main function
@@ -321,7 +321,7 @@ fn mk_main(cx: &mut TestCtxt<'_>) -> P<ast::Item> {
None => Ident::from_str_and_span("main", sp).gensym(),
};
- P(ast::Item {
+ let main = P(ast::Item {
ident: main_id,
attrs: vec![main_attr],
id: ast::DUMMY_NODE_ID,
@@ -329,8 +329,11 @@ fn mk_main(cx: &mut TestCtxt<'_>) -> P<ast::Item> {
vis: dummy_spanned(ast::VisibilityKind::Public),
span: sp,
tokens: None,
- })
+ });
+ // Integrate the new item into existing module structures.
+ let main = AstFragment::Items(smallvec![main]);
+ cx.ext_cx.monotonic_expander().fully_expand_fragment(main).make_items().pop().unwrap()
}
fn path_name_i(idents: &[Ident]) -> String {