diff options
| -rw-r--r-- | clippy_lints/src/matches/single_match.rs | 21 | ||||
| -rw-r--r-- | tests/ui/single_match_else_deref_patterns.fixed | 7 | ||||
| -rw-r--r-- | tests/ui/single_match_else_deref_patterns.rs | 11 | ||||
| -rw-r--r-- | tests/ui/single_match_else_deref_patterns.stderr | 16 |
4 files changed, 47 insertions, 8 deletions
diff --git a/clippy_lints/src/matches/single_match.rs b/clippy_lints/src/matches/single_match.rs index 08c0caa4266..811455c25e4 100644 --- a/clippy_lints/src/matches/single_match.rs +++ b/clippy_lints/src/matches/single_match.rs @@ -152,21 +152,26 @@ fn report_single_pattern( }) if lit.node.is_str() || lit.node.is_bytestr() => pat_ref_count + 1, _ => pat_ref_count, }; - // References are only implicitly added to the pattern, so no overflow here. - // e.g. will work: match &Some(_) { Some(_) => () } - // will not: match Some(_) { &Some(_) => () } - let ref_count_diff = ty_ref_count - pat_ref_count; - // Try to remove address of expressions first. - let (ex, removed) = peel_n_hir_expr_refs(ex, ref_count_diff); - let ref_count_diff = ref_count_diff - removed; + // References are implicitly removed when `deref_patterns` are used. + // They are implicitly added when match ergonomics are used. + let (ex, ref_or_deref_adjust) = if ty_ref_count > pat_ref_count { + let ref_count_diff = ty_ref_count - pat_ref_count; + + // Try to remove address of expressions first. + let (ex, removed) = peel_n_hir_expr_refs(ex, ref_count_diff); + + (ex, "&".repeat(ref_count_diff - removed)) + } else { + (ex, "*".repeat(pat_ref_count - ty_ref_count)) + }; let msg = "you seem to be trying to use `match` for an equality check. Consider using `if`"; let sugg = format!( "if {} == {}{} {}{els_str}", snippet_with_context(cx, ex.span, ctxt, "..", &mut app).0, // PartialEq for different reference counts may not exist. - "&".repeat(ref_count_diff), + ref_or_deref_adjust, snippet_with_applicability(cx, arm.pat.span, "..", &mut app), expr_block(cx, arm.body, ctxt, "..", Some(expr.span), &mut app), ); diff --git a/tests/ui/single_match_else_deref_patterns.fixed b/tests/ui/single_match_else_deref_patterns.fixed new file mode 100644 index 00000000000..c83e8c4a18f --- /dev/null +++ b/tests/ui/single_match_else_deref_patterns.fixed @@ -0,0 +1,7 @@ +#![feature(deref_patterns)] +#![allow(incomplete_features, clippy::eq_op)] +#![warn(clippy::single_match_else)] + +fn string() { + if *"" == *"" {} +} diff --git a/tests/ui/single_match_else_deref_patterns.rs b/tests/ui/single_match_else_deref_patterns.rs new file mode 100644 index 00000000000..c7dbfb4e465 --- /dev/null +++ b/tests/ui/single_match_else_deref_patterns.rs @@ -0,0 +1,11 @@ +#![feature(deref_patterns)] +#![allow(incomplete_features, clippy::eq_op)] +#![warn(clippy::single_match_else)] + +fn string() { + match *"" { + //~^ single_match + "" => {}, + _ => {}, + } +} diff --git a/tests/ui/single_match_else_deref_patterns.stderr b/tests/ui/single_match_else_deref_patterns.stderr new file mode 100644 index 00000000000..17959ce9a0c --- /dev/null +++ b/tests/ui/single_match_else_deref_patterns.stderr @@ -0,0 +1,16 @@ +error: you seem to be trying to use `match` for an equality check. Consider using `if` + --> tests/ui/single_match_else_deref_patterns.rs:6:5 + | +LL | / match *"" { +LL | | +LL | | "" => {}, +LL | | _ => {}, +LL | | } + | |_____^ help: try: `if *"" == *"" {}` + | + = note: you might want to preserve the comments from inside the `match` + = note: `-D clippy::single-match` implied by `-D warnings` + = help: to override `-D warnings` add `#[allow(clippy::single_match)]` + +error: aborting due to 1 previous error + |