diff options
| -rw-r--r-- | clippy_lints/src/methods/mod.rs | 25 | ||||
| -rw-r--r-- | clippy_lints/src/utils/paths.rs | 1 | ||||
| -rw-r--r-- | tests/ui/single_char_insert_str.fixed | 18 | ||||
| -rw-r--r-- | tests/ui/single_char_insert_str.rs | 18 | ||||
| -rw-r--r-- | tests/ui/single_char_insert_str.stderr | 40 |
5 files changed, 100 insertions, 2 deletions
diff --git a/clippy_lints/src/methods/mod.rs b/clippy_lints/src/methods/mod.rs index 3c3093e869c..86e7c57afae 100644 --- a/clippy_lints/src/methods/mod.rs +++ b/clippy_lints/src/methods/mod.rs @@ -1290,8 +1290,8 @@ declare_clippy_lint! { } declare_clippy_lint! { - /// **What it does:** Warns when using `push_str` with a single-character string literal, - /// and `push` with a `char` would work fine. + /// **What it does:** Warns when using `push_str` with a single-character string literal + /// where `push` with a `char` would work fine. /// /// **Why is this bad?** It's less clear that we are pushing a single character. /// @@ -1521,6 +1521,8 @@ impl<'tcx> LateLintPass<'tcx> for Methods { if let Some(fn_def_id) = cx.typeck_results().type_dependent_def_id(expr.hir_id) { if match_def_path(cx, fn_def_id, &paths::PUSH_STR) { lint_single_char_push_string(cx, expr, args); + } else if match_def_path(cx, fn_def_id, &paths::INSERT_STR) { + lint_single_char_insert_string(cx, expr, args); } } @@ -3255,6 +3257,25 @@ fn lint_single_char_push_string(cx: &LateContext<'_>, expr: &hir::Expr<'_>, args } } +/// lint for length-1 `str`s as argument for `insert_str` +fn lint_single_char_insert_string(cx: &LateContext<'_>, expr: &hir::Expr<'_>, args: &[hir::Expr<'_>]) { + let mut applicability = Applicability::MachineApplicable; + if let Some(extension_string) = get_hint_if_single_char_arg(cx, &args[2], &mut applicability) { + let base_string_snippet = snippet_with_applicability(cx, args[0].span, "_", &mut applicability); + let pos_arg = snippet(cx, args[1].span, ".."); + let sugg = format!("{}.insert({}, {})", base_string_snippet, pos_arg, extension_string); + span_lint_and_sugg( + cx, + SINGLE_CHAR_PUSH_STR, + expr.span, + "calling `insert_str()` using a single-character string literal", + "consider using `insert` with a character literal", + sugg, + applicability, + ); + } +} + /// Checks for the `USELESS_ASREF` lint. fn lint_asref(cx: &LateContext<'_>, expr: &hir::Expr<'_>, call_name: &str, as_ref_args: &[hir::Expr<'_>]) { // when we get here, we've already checked that the call name is "as_ref" or "as_mut" diff --git a/clippy_lints/src/utils/paths.rs b/clippy_lints/src/utils/paths.rs index cd72fdd61fd..34d5c8d2eb7 100644 --- a/clippy_lints/src/utils/paths.rs +++ b/clippy_lints/src/utils/paths.rs @@ -52,6 +52,7 @@ pub const HASHMAP_ENTRY: [&str; 5] = ["std", "collections", "hash", "map", "Entr pub const HASHSET: [&str; 5] = ["std", "collections", "hash", "set", "HashSet"]; pub const INDEX: [&str; 3] = ["core", "ops", "Index"]; pub const INDEX_MUT: [&str; 3] = ["core", "ops", "IndexMut"]; +pub const INSERT_STR: [&str; 4] = ["alloc", "string", "String", "insert_str"]; pub const INTO: [&str; 3] = ["core", "convert", "Into"]; pub const INTO_ITERATOR: [&str; 5] = ["core", "iter", "traits", "collect", "IntoIterator"]; pub const IO_READ: [&str; 3] = ["std", "io", "Read"]; diff --git a/tests/ui/single_char_insert_str.fixed b/tests/ui/single_char_insert_str.fixed new file mode 100644 index 00000000000..c3416720ec3 --- /dev/null +++ b/tests/ui/single_char_insert_str.fixed @@ -0,0 +1,18 @@ +// run-rustfix +#![warn(clippy::single_char_push_str)] + +fn main() { + let mut string = String::new(); + string.insert(0, 'R'); + string.insert(1, '\''); + + string.insert(0, 'u'); + string.insert_str(2, "st"); + string.insert_str(0, ""); + string.insert(0, '\x52'); + string.insert(0, '\u{0052}'); + let x: usize = 2; + string.insert(x, 'a'); + const Y: usize = 1; + string.insert(Y, 'a'); +} diff --git a/tests/ui/single_char_insert_str.rs b/tests/ui/single_char_insert_str.rs new file mode 100644 index 00000000000..2295669e81d --- /dev/null +++ b/tests/ui/single_char_insert_str.rs @@ -0,0 +1,18 @@ +// run-rustfix +#![warn(clippy::single_char_push_str)] + +fn main() { + let mut string = String::new(); + string.insert_str(0, "R"); + string.insert_str(1, "'"); + + string.insert(0, 'u'); + string.insert_str(2, "st"); + string.insert_str(0, ""); + string.insert_str(0, "\x52"); + string.insert_str(0, "\u{0052}"); + let x: usize = 2; + string.insert_str(x, r##"a"##); + const Y: usize = 1; + string.insert_str(Y, r##"a"##); +} diff --git a/tests/ui/single_char_insert_str.stderr b/tests/ui/single_char_insert_str.stderr new file mode 100644 index 00000000000..65dc8a69d69 --- /dev/null +++ b/tests/ui/single_char_insert_str.stderr @@ -0,0 +1,40 @@ +error: calling `insert_str()` using a single-character string literal + --> $DIR/single_char_insert_str.rs:6:5 + | +LL | string.insert_str(0, "R"); + | ^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `insert` with a character literal: `string.insert(0, 'R')` + | + = note: `-D clippy::single-char-push-str` implied by `-D warnings` + +error: calling `insert_str()` using a single-character string literal + --> $DIR/single_char_insert_str.rs:7:5 + | +LL | string.insert_str(1, "'"); + | ^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `insert` with a character literal: `string.insert(1, '/'')` + +error: calling `insert_str()` using a single-character string literal + --> $DIR/single_char_insert_str.rs:12:5 + | +LL | string.insert_str(0, "/x52"); + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `insert` with a character literal: `string.insert(0, '/x52')` + +error: calling `insert_str()` using a single-character string literal + --> $DIR/single_char_insert_str.rs:13:5 + | +LL | string.insert_str(0, "/u{0052}"); + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `insert` with a character literal: `string.insert(0, '/u{0052}')` + +error: calling `insert_str()` using a single-character string literal + --> $DIR/single_char_insert_str.rs:15:5 + | +LL | string.insert_str(x, r##"a"##); + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `insert` with a character literal: `string.insert(x, 'a')` + +error: calling `insert_str()` using a single-character string literal + --> $DIR/single_char_insert_str.rs:17:5 + | +LL | string.insert_str(Y, r##"a"##); + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `insert` with a character literal: `string.insert(Y, 'a')` + +error: aborting due to 6 previous errors + |