diff options
| -rw-r--r-- | clippy_lints/src/matches/mod.rs | 13 | ||||
| -rw-r--r-- | clippy_utils/src/hir_utils.rs | 156 | ||||
| -rw-r--r-- | clippy_utils/src/lib.rs | 34 | ||||
| -rw-r--r-- | clippy_utils/src/source.rs | 52 | ||||
| -rw-r--r-- | tests/ui/match_same_arms.rs | 48 |
5 files changed, 229 insertions, 74 deletions
diff --git a/clippy_lints/src/matches/mod.rs b/clippy_lints/src/matches/mod.rs index 87b63eead25..55ec9d4474f 100644 --- a/clippy_lints/src/matches/mod.rs +++ b/clippy_lints/src/matches/mod.rs @@ -25,9 +25,9 @@ mod wild_in_or_pats; use clippy_utils::msrvs::{self, Msrv}; use clippy_utils::source::{snippet_opt, walk_span_to_context}; -use clippy_utils::{higher, in_constant, is_span_match}; +use clippy_utils::{higher, in_constant, is_span_match, tokenize_with_text}; use rustc_hir::{Arm, Expr, ExprKind, Local, MatchSource, Pat}; -use rustc_lexer::{tokenize, TokenKind}; +use rustc_lexer::TokenKind; use rustc_lint::{LateContext, LateLintPass, LintContext}; use rustc_middle::lint::in_external_macro; use rustc_session::{declare_tool_lint, impl_lint_pass}; @@ -1147,12 +1147,7 @@ fn span_contains_cfg(cx: &LateContext<'_>, s: Span) -> bool { // Assume true. This would require either an invalid span, or one which crosses file boundaries. return true; }; - let mut pos = 0usize; - let mut iter = tokenize(&snip).map(|t| { - let start = pos; - pos += t.len as usize; - (t.kind, start..pos) - }); + let mut iter = tokenize_with_text(&snip); // Search for the token sequence [`#`, `[`, `cfg`] while iter.any(|(t, _)| matches!(t, TokenKind::Pound)) { @@ -1163,7 +1158,7 @@ fn span_contains_cfg(cx: &LateContext<'_>, s: Span) -> bool { ) }); if matches!(iter.next(), Some((TokenKind::OpenBracket, _))) - && matches!(iter.next(), Some((TokenKind::Ident, range)) if &snip[range.clone()] == "cfg") + && matches!(iter.next(), Some((TokenKind::Ident, "cfg"))) { return true; } diff --git a/clippy_utils/src/hir_utils.rs b/clippy_utils/src/hir_utils.rs index 9b7408d5133..3561e760ac9 100644 --- a/clippy_utils/src/hir_utils.rs +++ b/clippy_utils/src/hir_utils.rs @@ -1,6 +1,7 @@ use crate::consts::constant_simple; use crate::macros::macro_backtrace; -use crate::source::snippet_opt; +use crate::source::{get_source_text, snippet_opt, walk_span_to_context, SpanRange}; +use crate::tokenize_with_text; use rustc_ast::ast::InlineAsmTemplatePiece; use rustc_data_structures::fx::FxHasher; use rustc_hir::def::Res; @@ -13,8 +14,9 @@ use rustc_hir::{ use rustc_lexer::{tokenize, TokenKind}; use rustc_lint::LateContext; use rustc_middle::ty::TypeckResults; -use rustc_span::{sym, Symbol}; +use rustc_span::{sym, BytePos, Symbol, SyntaxContext}; use std::hash::{Hash, Hasher}; +use std::ops::Range; /// Callback that is called when two expressions are not equal in the sense of `SpanlessEq`, but /// other conditions would make them equal. @@ -127,51 +129,83 @@ impl HirEqInterExpr<'_, '_, '_> { /// Checks whether two blocks are the same. fn eq_block(&mut self, left: &Block<'_>, right: &Block<'_>) -> bool { - match (left.stmts, left.expr, right.stmts, right.expr) { - ([], None, [], None) => { - // For empty blocks, check to see if the tokens are equal. This will catch the case where a macro - // expanded to nothing, or the cfg attribute was used. - let (Some(left), Some(right)) = ( - snippet_opt(self.inner.cx, left.span), - snippet_opt(self.inner.cx, right.span), - ) else { return true }; - let mut left_pos = 0; - let left = tokenize(&left) - .map(|t| { - let end = left_pos + t.len as usize; - let s = &left[left_pos..end]; - left_pos = end; - (t, s) - }) - .filter(|(t, _)| { - !matches!( - t.kind, - TokenKind::LineComment { .. } | TokenKind::BlockComment { .. } | TokenKind::Whitespace - ) - }) - .map(|(_, s)| s); - let mut right_pos = 0; - let right = tokenize(&right) - .map(|t| { - let end = right_pos + t.len as usize; - let s = &right[right_pos..end]; - right_pos = end; - (t, s) - }) - .filter(|(t, _)| { - !matches!( - t.kind, - TokenKind::LineComment { .. } | TokenKind::BlockComment { .. } | TokenKind::Whitespace - ) - }) - .map(|(_, s)| s); - left.eq(right) - }, - _ => { - over(left.stmts, right.stmts, |l, r| self.eq_stmt(l, r)) - && both(&left.expr, &right.expr, |l, r| self.eq_expr(l, r)) - }, + use TokenKind::{BlockComment, LineComment, Semi, Whitespace}; + if left.stmts.len() != right.stmts.len() { + return false; } + let lspan = left.span.data(); + let rspan = right.span.data(); + if lspan.ctxt != SyntaxContext::root() && rspan.ctxt != SyntaxContext::root() { + // Don't try to check in between statements inside macros. + return over(left.stmts, right.stmts, |left, right| self.eq_stmt(left, right)) + && both(&left.expr, &right.expr, |left, right| self.eq_expr(left, right)); + } + if lspan.ctxt != rspan.ctxt { + return false; + } + + let mut lstart = lspan.lo; + let mut rstart = rspan.lo; + + for (left, right) in left.stmts.iter().zip(right.stmts) { + if !self.eq_stmt(left, right) { + return false; + } + let Some(lstmt_span) = walk_span_to_context(left.span, lspan.ctxt) else { + return false; + }; + let Some(rstmt_span) = walk_span_to_context(right.span, rspan.ctxt) else { + return false; + }; + let lstmt_span = lstmt_span.data(); + let rstmt_span = rstmt_span.data(); + + if lstmt_span.lo < lstart && rstmt_span.lo < rstart { + // Can happen when macros expand to multiple statements, or rearrange statements. + // Nothing in between the statements to check in this case. + continue; + } else if lstmt_span.lo < lstart || rstmt_span.lo < rstart { + // Only one of the blocks had a weird macro. + return false; + } + if !eq_span_tokens(self.inner.cx, lstart..lstmt_span.lo, rstart..rstmt_span.lo, |t| { + !matches!(t, Whitespace | LineComment { .. } | BlockComment { .. } | Semi) + }) { + return false; + } + + lstart = lstmt_span.hi; + rstart = rstmt_span.hi; + } + + let (lend, rend) = match (left.expr, right.expr) { + (Some(left), Some(right)) => { + if !self.eq_expr(left, right) { + return false; + } + let Some(lexpr_span) = walk_span_to_context(left.span, lspan.ctxt) else { + return false; + }; + let Some(rexpr_span) = walk_span_to_context(right.span, rspan.ctxt) else { + return false; + }; + (lexpr_span.lo(), rexpr_span.lo()) + }, + (None, None) => (lspan.hi, rspan.hi), + (Some(_), None) | (None, Some(_)) => return false, + }; + + if lend < lstart && rend < rstart { + // Can happen when macros rearrange the input. + // Nothing in between the statements to check in this case. + return true; + } else if lend < lstart || rend < rstart { + // Only one of the blocks had a weird macro + return false; + } + eq_span_tokens(self.inner.cx, lstart..lend, rstart..rend, |t| { + !matches!(t, Whitespace | LineComment { .. } | BlockComment { .. } | Semi) + }) } fn should_ignore(&mut self, expr: &Expr<'_>) -> bool { @@ -1038,3 +1072,33 @@ pub fn hash_expr(cx: &LateContext<'_>, e: &Expr<'_>) -> u64 { h.hash_expr(e); h.finish() } + +fn eq_span_tokens( + cx: &LateContext<'_>, + left: impl SpanRange, + right: impl SpanRange, + pred: impl Fn(TokenKind) -> bool, +) -> bool { + fn f(cx: &LateContext<'_>, left: Range<BytePos>, right: Range<BytePos>, pred: impl Fn(TokenKind) -> bool) -> bool { + if let Some(lsrc) = get_source_text(cx, left) + && let Some(lsrc) = lsrc.as_str() + && let Some(rsrc) = get_source_text(cx, right) + && let Some(rsrc) = rsrc.as_str() + { + let pred = |t: &(_, _)| pred(t.0); + let map = |(_, x)| x; + + let ltok = tokenize_with_text(lsrc) + .filter(pred) + .map(map); + let rtok = tokenize_with_text(rsrc) + .filter(pred) + .map(map); + ltok.eq(rtok) + } else { + // Unable to access the source. Conservatively assume the blocks aren't equal. + false + } + } + f(cx, left.into_range(), right.into_range(), pred) +} diff --git a/clippy_utils/src/lib.rs b/clippy_utils/src/lib.rs index 2e27c260f74..2ddd2ade6ae 100644 --- a/clippy_utils/src/lib.rs +++ b/clippy_utils/src/lib.rs @@ -77,6 +77,7 @@ use std::sync::OnceLock; use std::sync::{Mutex, MutexGuard}; use if_chain::if_chain; +use itertools::Itertools; use rustc_ast::ast::{self, LitKind, RangeLimits}; use rustc_ast::Attribute; use rustc_data_structures::fx::FxHashMap; @@ -2490,6 +2491,17 @@ pub fn walk_to_expr_usage<'tcx, T>( None } +/// Tokenizes the input while keeping the text associated with each token. +pub fn tokenize_with_text(s: &str) -> impl Iterator<Item = (TokenKind, &str)> { + let mut pos = 0; + tokenize(s).map(move |t| { + let end = pos + t.len; + let range = pos as usize..end as usize; + pos = end; + (t.kind, s.get(range).unwrap_or_default()) + }) +} + /// Checks whether a given span has any comment token /// This checks for all types of comment: line "//", block "/**", doc "///" "//!" pub fn span_contains_comment(sm: &SourceMap, span: Span) -> bool { @@ -2506,23 +2518,11 @@ pub fn span_contains_comment(sm: &SourceMap, span: Span) -> bool { /// Comments are returned wrapped with their relevant delimiters pub fn span_extract_comment(sm: &SourceMap, span: Span) -> String { let snippet = sm.span_to_snippet(span).unwrap_or_default(); - let mut comments_buf: Vec<String> = Vec::new(); - let mut index: usize = 0; - - for token in tokenize(&snippet) { - let token_range = index..(index + token.len as usize); - index += token.len as usize; - match token.kind { - TokenKind::BlockComment { .. } | TokenKind::LineComment { .. } => { - if let Some(comment) = snippet.get(token_range) { - comments_buf.push(comment.to_string()); - } - }, - _ => (), - } - } - - comments_buf.join("\n") + let res = tokenize_with_text(&snippet) + .filter(|(t, _)| matches!(t, TokenKind::BlockComment { .. } | TokenKind::LineComment { .. })) + .map(|(_, s)| s) + .join("\n"); + res } pub fn span_find_starting_semi(sm: &SourceMap, span: Span) -> Span { diff --git a/clippy_utils/src/source.rs b/clippy_utils/src/source.rs index 62fa37660fa..0f60290644a 100644 --- a/clippy_utils/src/source.rs +++ b/clippy_utils/src/source.rs @@ -2,14 +2,64 @@ #![allow(clippy::module_name_repetitions)] +use rustc_data_structures::sync::Lrc; use rustc_errors::Applicability; use rustc_hir::{Expr, ExprKind}; use rustc_lint::{LateContext, LintContext}; use rustc_session::Session; -use rustc_span::hygiene; use rustc_span::source_map::{original_sp, SourceMap}; +use rustc_span::{hygiene, SourceFile}; use rustc_span::{BytePos, Pos, Span, SpanData, SyntaxContext, DUMMY_SP}; use std::borrow::Cow; +use std::ops::Range; + +/// A type which can be converted to the range portion of a `Span`. +pub trait SpanRange { + fn into_range(self) -> Range<BytePos>; +} +impl SpanRange for Span { + fn into_range(self) -> Range<BytePos> { + let data = self.data(); + data.lo..data.hi + } +} +impl SpanRange for SpanData { + fn into_range(self) -> Range<BytePos> { + self.lo..self.hi + } +} +impl SpanRange for Range<BytePos> { + fn into_range(self) -> Range<BytePos> { + self + } +} + +pub struct SourceFileRange { + pub sf: Lrc<SourceFile>, + pub range: Range<usize>, +} +impl SourceFileRange { + /// Attempts to get the text from the source file. This can fail if the source text isn't + /// loaded. + pub fn as_str(&self) -> Option<&str> { + self.sf.src.as_ref().and_then(|x| x.get(self.range.clone())) + } +} + +/// Gets the source file, and range in the file, of the given span. Returns `None` if the span +/// extends through multiple files, or is malformed. +pub fn get_source_text(cx: &impl LintContext, sp: impl SpanRange) -> Option<SourceFileRange> { + fn f(sm: &SourceMap, sp: Range<BytePos>) -> Option<SourceFileRange> { + let start = sm.lookup_byte_offset(sp.start); + let end = sm.lookup_byte_offset(sp.end); + if !Lrc::ptr_eq(&start.sf, &end.sf) || start.pos > end.pos { + return None; + } + let range = start.pos.to_usize()..end.pos.to_usize(); + Some(SourceFileRange { sf: start.sf, range }) + } + f(cx.sess().source_map(), sp.into_range()) +} /// Like `snippet_block`, but add braces if the expr is not an `ExprKind::Block`. pub fn expr_block<T: LintContext>( diff --git a/tests/ui/match_same_arms.rs b/tests/ui/match_same_arms.rs index 0b9342c9c42..15410734dec 100644 --- a/tests/ui/match_same_arms.rs +++ b/tests/ui/match_same_arms.rs @@ -53,4 +53,50 @@ mod issue4244 { } } -fn main() {} +macro_rules! m { + (foo) => {}; + (bar) => {}; +} + +fn main() { + let x = 0; + let _ = match 0 { + 0 => { + m!(foo); + x + }, + 1 => { + m!(bar); + x + }, + _ => 1, + }; + + let _ = match 0 { + 0 => { + let mut x = 0; + #[cfg(not_enabled)] + { + x = 5; + } + #[cfg(not(not_enabled))] + { + x = 6; + } + x + }, + 1 => { + let mut x = 0; + #[cfg(also_not_enabled)] + { + x = 5; + } + #[cfg(not(also_not_enabled))] + { + x = 6; + } + x + }, + _ => 0, + }; +} |