use rustc_hir::{Expr, ExprKind};
use rustc_lint::{LateContext, LintContext};
use rustc_span::hygiene;
+use rustc_span::source_map::SourceMap;
use rustc_span::{BytePos, Pos, Span, 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>(
true
}
-/// Returns the positon just before rarrow
+/// Returns the position just before rarrow
///
/// ```rust,ignore
/// fn into(self) -> () {}