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Merge pull request #20265 from ChayimFriedman2/cfg-select
feat: Support `cfg_select!`
| -rw-r--r-- | crates/cfg/src/cfg_expr.rs | 14 | ||||
| -rw-r--r-- | crates/hir-def/src/macro_expansion_tests/builtin_fn_macro.rs | 48 | ||||
| -rw-r--r-- | crates/hir-expand/src/builtin/fn_macro.rs | 66 | ||||
| -rw-r--r-- | crates/intern/src/symbol/symbols.rs | 1 | ||||
| -rw-r--r-- | crates/tt/src/iter.rs | 11 |
5 files changed, 139 insertions, 1 deletions
diff --git a/crates/cfg/src/cfg_expr.rs b/crates/cfg/src/cfg_expr.rs index 0ec082dfa7..aed00aa9fc 100644 --- a/crates/cfg/src/cfg_expr.rs +++ b/crates/cfg/src/cfg_expr.rs @@ -68,6 +68,11 @@ impl CfgExpr { next_cfg_expr(&mut tt.iter()).unwrap_or(CfgExpr::Invalid) } + #[cfg(feature = "tt")] + pub fn parse_from_iter<S: Copy>(tt: &mut tt::iter::TtIter<'_, S>) -> CfgExpr { + next_cfg_expr(tt).unwrap_or(CfgExpr::Invalid) + } + /// Fold the cfg by querying all basic `Atom` and `KeyValue` predicates. pub fn fold(&self, query: &dyn Fn(&CfgAtom) -> bool) -> Option<bool> { match self { @@ -96,7 +101,14 @@ fn next_cfg_expr<S: Copy>(it: &mut tt::iter::TtIter<'_, S>) -> Option<CfgExpr> { }; let ret = match it.peek() { - Some(TtElement::Leaf(tt::Leaf::Punct(punct))) if punct.char == '=' => { + Some(TtElement::Leaf(tt::Leaf::Punct(punct))) + // Don't consume on e.g. `=>`. + if punct.char == '=' + && (punct.spacing == tt::Spacing::Alone + || it.remaining().flat_tokens().get(1).is_none_or(|peek2| { + !matches!(peek2, tt::TokenTree::Leaf(tt::Leaf::Punct(_))) + })) => + { match it.remaining().flat_tokens().get(1) { Some(tt::TokenTree::Leaf(tt::Leaf::Literal(literal))) => { it.next(); diff --git a/crates/hir-def/src/macro_expansion_tests/builtin_fn_macro.rs b/crates/hir-def/src/macro_expansion_tests/builtin_fn_macro.rs index 1c3af47d52..eeaf865338 100644 --- a/crates/hir-def/src/macro_expansion_tests/builtin_fn_macro.rs +++ b/crates/hir-def/src/macro_expansion_tests/builtin_fn_macro.rs @@ -550,3 +550,51 @@ fn main() { "\"hello\""; } "##]], ); } + +#[test] +fn cfg_select() { + check( + r#" +#[rustc_builtin_macro] +pub macro cfg_select($($tt:tt)*) {} + +cfg_select! { + false => { fn false_1() {} } + any(false, true) => { fn true_1() {} } +} + +cfg_select! { + false => { fn false_2() {} } + _ => { fn true_2() {} } +} + +cfg_select! { + false => { fn false_3() {} } +} + +cfg_select! { + false +} + +cfg_select! { + false => +} + + "#, + expect![[r#" +#[rustc_builtin_macro] +pub macro cfg_select($($tt:tt)*) {} + +fn true_1() {} + +fn true_2() {} + +/* error: none of the predicates in this `cfg_select` evaluated to true */ + +/* error: expected `=>` after cfg expression */ + +/* error: expected a token tree after `=>` */ + + "#]], + ); +} diff --git a/crates/hir-expand/src/builtin/fn_macro.rs b/crates/hir-expand/src/builtin/fn_macro.rs index 60fbc66065..4a9af01091 100644 --- a/crates/hir-expand/src/builtin/fn_macro.rs +++ b/crates/hir-expand/src/builtin/fn_macro.rs @@ -127,6 +127,7 @@ register_builtin! { (asm, Asm) => asm_expand, (global_asm, GlobalAsm) => global_asm_expand, (naked_asm, NakedAsm) => naked_asm_expand, + (cfg_select, CfgSelect) => cfg_select_expand, (cfg, Cfg) => cfg_expand, (core_panic, CorePanic) => panic_expand, (std_panic, StdPanic) => panic_expand, @@ -355,6 +356,71 @@ fn naked_asm_expand( ExpandResult::ok(expanded) } +fn cfg_select_expand( + db: &dyn ExpandDatabase, + id: MacroCallId, + tt: &tt::TopSubtree, + span: Span, +) -> ExpandResult<tt::TopSubtree> { + let loc = db.lookup_intern_macro_call(id); + let cfg_options = loc.krate.cfg_options(db); + + let mut iter = tt.iter(); + let mut expand_to = None; + while let Some(next) = iter.peek() { + let active = if let tt::TtElement::Leaf(tt::Leaf::Ident(ident)) = next + && ident.sym == sym::underscore + { + iter.next(); + true + } else { + cfg_options.check(&CfgExpr::parse_from_iter(&mut iter)) != Some(false) + }; + match iter.expect_glued_punct() { + Ok(it) if it.len() == 2 && it[0].char == '=' && it[1].char == '>' => {} + _ => { + let err_span = iter.peek().map(|it| it.first_span()).unwrap_or(span); + return ExpandResult::new( + tt::TopSubtree::empty(tt::DelimSpan::from_single(span)), + ExpandError::other(err_span, "expected `=>` after cfg expression"), + ); + } + } + let expand_to_if_active = match iter.next() { + Some(tt::TtElement::Subtree(_, tt)) => tt.remaining(), + _ => { + let err_span = iter.peek().map(|it| it.first_span()).unwrap_or(span); + return ExpandResult::new( + tt::TopSubtree::empty(tt::DelimSpan::from_single(span)), + ExpandError::other(err_span, "expected a token tree after `=>`"), + ); + } + }; + + if expand_to.is_none() && active { + expand_to = Some(expand_to_if_active); + } + } + match expand_to { + Some(expand_to) => { + let mut builder = tt::TopSubtreeBuilder::new(tt::Delimiter { + kind: tt::DelimiterKind::Invisible, + open: span, + close: span, + }); + builder.extend_with_tt(expand_to); + ExpandResult::ok(builder.build()) + } + None => ExpandResult::new( + tt::TopSubtree::empty(tt::DelimSpan::from_single(span)), + ExpandError::other( + span, + "none of the predicates in this `cfg_select` evaluated to true", + ), + ), + } +} + fn cfg_expand( db: &dyn ExpandDatabase, id: MacroCallId, diff --git a/crates/intern/src/symbol/symbols.rs b/crates/intern/src/symbol/symbols.rs index 1ccd20c25e..4780743c4d 100644 --- a/crates/intern/src/symbol/symbols.rs +++ b/crates/intern/src/symbol/symbols.rs @@ -156,6 +156,7 @@ define_symbols! { cfg_attr, cfg_eval, cfg, + cfg_select, char, clone, Clone, diff --git a/crates/tt/src/iter.rs b/crates/tt/src/iter.rs index 3246156f1c..2e89d762a0 100644 --- a/crates/tt/src/iter.rs +++ b/crates/tt/src/iter.rs @@ -217,6 +217,17 @@ pub enum TtElement<'a, S> { Subtree(&'a Subtree<S>, TtIter<'a, S>), } +impl<S: Copy + fmt::Debug> fmt::Debug for TtElement<'_, S> { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + match self { + Self::Leaf(leaf) => f.debug_tuple("Leaf").field(leaf).finish(), + Self::Subtree(subtree, inner) => { + f.debug_tuple("Subtree").field(subtree).field(inner).finish() + } + } + } +} + impl<S: Copy> TtElement<'_, S> { #[inline] pub fn first_span(&self) -> S { |