Auto merge of #77135 - Aaron1011:pretty-ignore-paren, r=petrochenkov

Refactor AST pretty-printing to allow skipping insertion of extra parens

Fixes #75734
Makes progress towards #43081
Unblocks PR #76130

When pretty-printing an AST node, we may insert additional parenthesis
to ensure that precedence is properly preserved in code we output.
However, the proc macro implementation relies on comparing a
pretty-printed AST node to the captured `TokenStream`. Inserting extra
parenthesis changes the structure of the reparsed `TokenStream`, making
the comparison fail.

This PR refactors the AST pretty-printing code to allow skipping the
insertion of additional parenthesis. Several freestanding methods are
moved to trait methods on `PrintState`, which keep track of an internal
`insert_extra_parens` flag. This flag is normally `true`, but we expose
a public method which allows pretty-printing a nonterminal with
`insert_extra_parens = false`.

To avoid changing the public interface of `rustc_ast_pretty`, the
freestanding `_to_string` methods are changed to delegate to a
newly-crated `State`. The main pretty-printing code is moved to a new
`state` module to ensure that it does not accidentally call any of these
public helper functions (instead, the internal functions with the same
name should be used).

Author: bors

compiler/rustc_ast/src/token.rs

@@ -810,25 +810,36 @@ impl Nonterminal {
             if let ExpnKind::Macro(_, macro_name) = orig_span.ctxt().outer_expn_data().kind {
                 let filename = source_map.span_to_filename(orig_span);
                 if let FileName::Real(RealFileName::Named(path)) = filename {
-                    let matches_prefix = |prefix| {
-                        // Check for a path that ends with 'prefix*/src/lib.rs'
+                    let matches_prefix = |prefix, filename| {
+                        // Check for a path that ends with 'prefix*/src/<filename>'
                         let mut iter = path.components().rev();
-                        iter.next().and_then(|p| p.as_os_str().to_str()) == Some("lib.rs")
+                        iter.next().and_then(|p| p.as_os_str().to_str()) == Some(filename)
                             && iter.next().and_then(|p| p.as_os_str().to_str()) == Some("src")
                             && iter
                                 .next()
                                 .and_then(|p| p.as_os_str().to_str())
                                 .map_or(false, |p| p.starts_with(prefix))
                     };
 
-                    if (macro_name == sym::impl_macros && matches_prefix("time-macros-impl"))
-                        || (macro_name == sym::arrays && matches_prefix("js-sys"))
+                    if (macro_name == sym::impl_macros
+                        && matches_prefix("time-macros-impl", "lib.rs"))
+                        || (macro_name == sym::arrays && matches_prefix("js-sys", "lib.rs"))
                     {
                         let snippet = source_map.span_to_snippet(orig_span);
                         if snippet.as_deref() == Ok("$name") {
                             return Some((*ident, *is_raw));
                         }
                     }
+
+                    if macro_name == sym::tuple_from_req
+                        && (matches_prefix("actix-web", "extract.rs")
+                            || matches_prefix("actori-web", "extract.rs"))
+                    {
+                        let snippet = source_map.span_to_snippet(orig_span);
+                        if snippet.as_deref() == Ok("$T") {
+                            return Some((*ident, *is_raw));
+                        }
+                    }
                 }
             }
         }

compiler/rustc_ast_pretty/src/pprust/mod.rs

@@ -0,0 +1,104 @@
+#[cfg(test)]
+mod tests;
+
+pub mod state;
+pub use state::{print_crate, AnnNode, Comments, PpAnn, PrintState, State};
+
+use rustc_ast as ast;
+use rustc_ast::token::{Nonterminal, Token, TokenKind};
+use rustc_ast::tokenstream::{TokenStream, TokenTree};
+
+pub fn nonterminal_to_string_no_extra_parens(nt: &Nonterminal) -> String {
+    let state = State::without_insert_extra_parens();
+    state.nonterminal_to_string(nt)
+}
+
+pub fn nonterminal_to_string(nt: &Nonterminal) -> String {
+    State::new().nonterminal_to_string(nt)
+}
+
+/// Print the token kind precisely, without converting `$crate` into its respective crate name.
+pub fn token_kind_to_string(tok: &TokenKind) -> String {
+    State::new().token_kind_to_string(tok)
+}
+
+/// Print the token precisely, without converting `$crate` into its respective crate name.
+pub fn token_to_string(token: &Token) -> String {
+    State::new().token_to_string(token)
+}
+
+pub fn token_to_string_ext(token: &Token, convert_dollar_crate: bool) -> String {
+    State::new().token_to_string_ext(token, convert_dollar_crate)
+}
+
+pub fn ty_to_string(ty: &ast::Ty) -> String {
+    State::new().ty_to_string(ty)
+}
+
+pub fn bounds_to_string(bounds: &[ast::GenericBound]) -> String {
+    State::new().bounds_to_string(bounds)
+}
+
+pub fn pat_to_string(pat: &ast::Pat) -> String {
+    State::new().pat_to_string(pat)
+}
+
+pub fn expr_to_string(e: &ast::Expr) -> String {
+    State::new().expr_to_string(e)
+}
+
+pub fn tt_to_string(tt: &TokenTree) -> String {
+    State::new().tt_to_string(tt)
+}
+
+pub fn tts_to_string(tokens: &TokenStream) -> String {
+    State::new().tts_to_string(tokens)
+}
+
+pub fn stmt_to_string(stmt: &ast::Stmt) -> String {
+    State::new().stmt_to_string(stmt)
+}
+
+pub fn item_to_string(i: &ast::Item) -> String {
+    State::new().item_to_string(i)
+}
+
+pub fn generic_params_to_string(generic_params: &[ast::GenericParam]) -> String {
+    State::new().generic_params_to_string(generic_params)
+}
+
+pub fn path_to_string(p: &ast::Path) -> String {
+    State::new().path_to_string(p)
+}
+
+pub fn path_segment_to_string(p: &ast::PathSegment) -> String {
+    State::new().path_segment_to_string(p)
+}
+
+pub fn vis_to_string(v: &ast::Visibility) -> String {
+    State::new().vis_to_string(v)
+}
+
+pub fn block_to_string(blk: &ast::Block) -> String {
+    State::new().block_to_string(blk)
+}
+
+pub fn meta_list_item_to_string(li: &ast::NestedMetaItem) -> String {
+    State::new().meta_list_item_to_string(li)
+}
+
+pub fn attr_item_to_string(ai: &ast::AttrItem) -> String {
+    State::new().attr_item_to_string(ai)
+}
+
+pub fn attribute_to_string(attr: &ast::Attribute) -> String {
+    State::new().attribute_to_string(attr)
+}
+
+pub fn param_to_string(arg: &ast::Param) -> String {
+    State::new().param_to_string(arg)
+}
+
+pub fn to_string(f: impl FnOnce(&mut State<'_>)) -> String {
+    State::new().to_string(f)
+}