Rollup merge of #97794 - eltociear:patch-13, r=matthiaskrgr

[rust.git] / clippy_utils / src / source.rs

diff --git a/clippy_utils/src/source.rs b/clippy_utils/src/source.rs
index dbad607c58ea34dfee9b37780b166824cd0f2efc..f88a92fb11c111146851e4213a6508c0ec26b2ac 100644 (file)
--- a/clippy_utils/src/source.rs
+++ b/clippy_utils/src/source.rs
@@ -7,9 +7,28 @@
 use rustc_hir::{Expr, ExprKind};
 use rustc_lint::{LateContext, LintContext};
 use rustc_span::hygiene;
-use rustc_span::{BytePos, Pos, Span, SyntaxContext};
+use rustc_span::source_map::SourceMap;
+use rustc_span::{BytePos, Pos, Span, SpanData, SyntaxContext};
 use std::borrow::Cow;
 
+/// Checks if the span starts with the given text. This will return false if the span crosses
+/// multiple files or if source is not available.
+///
+/// This is used to check for proc macros giving unhelpful spans to things.
+pub fn span_starts_with<T: LintContext>(cx: &T, span: Span, text: &str) -> bool {
+    fn helper(sm: &SourceMap, span: Span, text: &str) -> bool {
+        let pos = sm.lookup_byte_offset(span.lo());
+        let Some(ref src) = pos.sf.src else {
+            return false;
+        };
+        let end = span.hi() - pos.sf.start_pos;
+        src.get(pos.pos.0 as usize..end.0 as usize)
+            // Expression spans can include wrapping parenthesis. Remove them first.
+            .map_or(false, |s| s.trim_start_matches('(').starts_with(text))
+    }
+    helper(cx.sess().source_map(), span, text)
+}
+
 /// Like `snippet_block`, but add braces if the expr is not an `ExprKind::Block`.
 /// Also takes an `Option<String>` which can be put inside the braces.
 pub fn expr_block<'a, T: LintContext>(
@@ -89,7 +108,7 @@ pub fn is_present_in_source<T: LintContext>(cx: &T, span: Span) -> bool {
     true
 }
 
-/// Returns the positon just before rarrow
+/// Returns the position just before rarrow
 ///
 /// ```rust,ignore
 /// fn into(self) -> () {}
@@ -118,7 +137,7 @@ pub fn position_before_rarrow(s: &str) -> Option<usize> {
 }
 
 /// Reindent a multiline string with possibility of ignoring the first line.
-#[allow(clippy::needless_pass_by_value)]
+#[expect(clippy::needless_pass_by_value)]
 pub fn reindent_multiline(s: Cow<'_, str>, ignore_first: bool, indent: Option<usize>) -> Cow<'_, str> {
     let s_space = reindent_multiline_inner(&s, ignore_first, indent, ' ');
     let s_tab = reindent_multiline_inner(&s_space, ignore_first, indent, '\t');
@@ -370,6 +389,27 @@ pub fn without_block_comments(lines: Vec<&str>) -> Vec<&str> {
     without
 }
 
+/// Trims the whitespace from the start and the end of the span.
+pub fn trim_span(sm: &SourceMap, span: Span) -> Span {
+    let data = span.data();
+    let sf: &_ = &sm.lookup_source_file(data.lo);
+    let Some(src) = sf.src.as_deref() else {
+        return span;
+    };
+    let Some(snip) = &src.get((data.lo - sf.start_pos).to_usize()..(data.hi - sf.start_pos).to_usize()) else {
+        return span;
+    };
+    let trim_start = snip.len() - snip.trim_start().len();
+    let trim_end = snip.len() - snip.trim_end().len();
+    SpanData {
+        lo: data.lo + BytePos::from_usize(trim_start),
+        hi: data.hi - BytePos::from_usize(trim_end),
+        ctxt: data.ctxt,
+        parent: data.parent,
+    }
+    .span()
+}
+
 #[cfg(test)]
 mod test {
     use super::{reindent_multiline, without_block_comments};