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Refactor format macro parsing

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This commit is contained in:
Cameron Steffen 2021-07-06 11:51:15 -05:00
parent 20dbb277cf
commit e6ab222b81
5 changed files with 203 additions and 217 deletions
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44
clippy_lints/src/explicit_write.rs
View file

@ -1,9 +1,9 @@
use clippy_utils::diagnostics::{span_lint, span_lint_and_sugg};
use clippy_utils::higher::FormatArgsExpn;
use clippy_utils::{is_expn_of, match_function_call, paths};
use if_chain::if_chain;
use rustc_ast::ast::LitKind;
use rustc_errors::Applicability;
use rustc_hir::{BorrowKind, Expr, ExprKind};
use rustc_hir::{Expr, ExprKind};
use rustc_lint::{LateContext, LateLintPass};
use rustc_session::{declare_lint_pass, declare_tool_lint};
use rustc_span::sym;
@ -34,29 +34,26 @@ impl<'tcx> LateLintPass<'tcx> for ExplicitWrite {
fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
if_chain! {
// match call to unwrap
if let ExprKind::MethodCall(unwrap_fun, _, unwrap_args, _) = expr.kind;
if let ExprKind::MethodCall(unwrap_fun, _, [write_call], _) = expr.kind;
if unwrap_fun.ident.name == sym::unwrap;
// match call to write_fmt
if !unwrap_args.is_empty();
if let ExprKind::MethodCall(write_fun, _, write_args, _) =
unwrap_args[0].kind;
if let ExprKind::MethodCall(write_fun, _, [write_recv, write_arg], _) = write_call.kind;
if write_fun.ident.name == sym!(write_fmt);
// match calls to std::io::stdout() / std::io::stderr ()
if !write_args.is_empty();
if let Some(dest_name) = if match_function_call(cx, &write_args[0], &paths::STDOUT).is_some() {
if let Some(dest_name) = if match_function_call(cx, write_recv, &paths::STDOUT).is_some() {
Some("stdout")
} else if match_function_call(cx, &write_args[0], &paths::STDERR).is_some() {
} else if match_function_call(cx, write_recv, &paths::STDERR).is_some() {
Some("stderr")
} else {
None
};
if let Some(format_args) = FormatArgsExpn::parse(write_arg);
then {
let write_span = unwrap_args[0].span;
let calling_macro =
// ordering is important here, since `writeln!` uses `write!` internally
if is_expn_of(write_span, "writeln").is_some() {
if is_expn_of(write_call.span, "writeln").is_some() {
Some("writeln")
} else if is_expn_of(write_span, "write").is_some() {
} else if is_expn_of(write_call.span, "write").is_some() {
Some("write")
} else {
None
@ -70,7 +67,8 @@ impl<'tcx> LateLintPass<'tcx> for ExplicitWrite {
// We need to remove the last trailing newline from the string because the
// underlying `fmt::write` function doesn't know whether `println!` or `print!` was
// used.
if let Some(mut write_output) = write_output_string(write_args) {
if let [write_output] = *format_args.format_string_symbols {
let mut write_output = write_output.to_string();
if write_output.ends_with('\n') {
write_output.pop();
}
@ -129,23 +127,3 @@ impl<'tcx> LateLintPass<'tcx> for ExplicitWrite {
}
}
}
// Extract the output string from the given `write_args`.
fn write_output_string(write_args: &[Expr<'_>]) -> Option<String> {
if_chain! {
// Obtain the string that should be printed
if write_args.len() > 1;
if let ExprKind::Call(_, output_args) = write_args[1].kind;
if !output_args.is_empty();
if let ExprKind::AddrOf(BorrowKind::Ref, _, output_string_expr) = output_args[0].kind;
if let ExprKind::Array(string_exprs) = output_string_expr.kind;
// we only want to provide an automatic suggestion for simple (non-format) strings
if string_exprs.len() == 1;
if let ExprKind::Lit(ref lit) = string_exprs[0].kind;
if let LitKind::Str(ref write_output, _) = lit.node;
then {
return Some(write_output.to_string())
}
}
None
}

192
clippy_lints/src/format.rs
View file

@ -1,18 +1,16 @@
use clippy_utils::diagnostics::span_lint_and_then;
use clippy_utils::paths;
use clippy_utils::source::{snippet, snippet_opt};
use clippy_utils::diagnostics::span_lint_and_sugg;
use clippy_utils::higher::FormatExpn;
use clippy_utils::last_path_segment;
use clippy_utils::source::{snippet_opt, snippet_with_applicability};
use clippy_utils::sugg::Sugg;
use clippy_utils::ty::is_type_diagnostic_item;
use clippy_utils::{is_expn_of, last_path_segment, match_def_path, match_function_call};
use if_chain::if_chain;
use rustc_ast::ast::LitKind;
use rustc_errors::Applicability;
use rustc_hir::{Arm, BorrowKind, Expr, ExprKind, MatchSource, PatKind};
use rustc_lint::{LateContext, LateLintPass, LintContext};
use rustc_hir::{BorrowKind, Expr, ExprKind, QPath};
use rustc_lint::{LateContext, LateLintPass};
use rustc_middle::ty;
use rustc_session::{declare_lint_pass, declare_tool_lint};
use rustc_span::source_map::Span;
use rustc_span::sym;
use rustc_span::symbol::kw;
use rustc_span::{sym, Span};
declare_clippy_lint! {
/// **What it does:** Checks for the use of `format!("string literal with no
@ -45,131 +43,78 @@ declare_lint_pass!(UselessFormat => [USELESS_FORMAT]);
impl<'tcx> LateLintPass<'tcx> for UselessFormat {
fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
let span = match is_expn_of(expr.span, "format") {
Some(s) if !s.from_expansion() => s,
let FormatExpn { call_site, format_args } = match FormatExpn::parse(expr) {
Some(e) if !e.call_site.from_expansion() => e,
_ => return,
};
// Operate on the only argument of `alloc::fmt::format`.
if let Some(sugg) = on_new_v1(cx, expr) {
span_useless_format(cx, span, "consider using `.to_string()`", sugg);
} else if let Some(sugg) = on_new_v1_fmt(cx, expr) {
span_useless_format(cx, span, "consider using `.to_string()`", sugg);
}
let mut applicability = Applicability::MachineApplicable;
if format_args.value_args.is_empty() {
if_chain! {
if let [e] = &*format_args.format_string_parts;
if let ExprKind::Lit(lit) = &e.kind;
if let Some(s_src) = snippet_opt(cx, lit.span);
then {
// Simulate macro expansion, converting {{ and }} to { and }.
let s_expand = s_src.replace("{{", "{").replace("}}", "}");
let sugg = format!("{}.to_string()", s_expand);
span_useless_format(cx, call_site, sugg, applicability);
}
}
} else if let [value] = *format_args.value_args {
if_chain! {
if format_args.format_string_symbols == [kw::Empty];
if match cx.typeck_results().expr_ty(value).peel_refs().kind() {
ty::Adt(adt, _) => cx.tcx.is_diagnostic_item(sym::string_type, adt.did),
ty::Str => true,
_ => false,
};
if format_args.args.iter().all(|e| is_display_arg(e));
if format_args.fmt_expr.map_or(true, |e| check_unformatted(e));
then {
let is_new_string = match value.kind {
ExprKind::Binary(..) => true,
ExprKind::MethodCall(path, ..) => path.ident.name.as_str() == "to_string",
_ => false,
};
let sugg = if is_new_string {
snippet_with_applicability(cx, value.span, "..", &mut applicability).into_owned()
} else {
let sugg = Sugg::hir_with_applicability(cx, value, "<arg>", &mut applicability);
format!("{}.to_string()", sugg.maybe_par())
};
span_useless_format(cx, call_site, sugg, applicability);
}
}
};
}
}
fn span_useless_format<T: LintContext>(cx: &T, span: Span, help: &str, mut sugg: String) {
let to_replace = span.source_callsite();
fn span_useless_format(cx: &LateContext<'_>, span: Span, mut sugg: String, mut applicability: Applicability) {
// The callsite span contains the statement semicolon for some reason.
let snippet = snippet(cx, to_replace, "..");
if snippet.ends_with(';') {
if snippet_with_applicability(cx, span, "..", &mut applicability).ends_with(';') {
sugg.push(';');
}
span_lint_and_then(cx, USELESS_FORMAT, span, "useless use of `format!`", |diag| {
diag.span_suggestion(
to_replace,
help,
sugg,
Applicability::MachineApplicable, // snippet
);
});
span_lint_and_sugg(
cx,
USELESS_FORMAT,
span,
"useless use of `format!`",
"consider using `.to_string()`",
sugg,
applicability,
);
}
fn on_argumentv1_new<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>, arms: &'tcx [Arm<'_>]) -> Option<String> {
fn is_display_arg(expr: &Expr<'_>) -> bool {
if_chain! {
if let ExprKind::AddrOf(BorrowKind::Ref, _, format_args) = expr.kind;
if let ExprKind::Array(elems) = arms[0].body.kind;
if elems.len() == 1;
if let Some(args) = match_function_call(cx, &elems[0], &paths::FMT_ARGUMENTV1_NEW);
// matches `core::fmt::Display::fmt`
if args.len() == 2;
if let ExprKind::Path(ref qpath) = args[1].kind;
if let Some(did) = cx.qpath_res(qpath, args[1].hir_id).opt_def_id();
if match_def_path(cx, did, &paths::DISPLAY_FMT_METHOD);
// check `(arg0,)` in match block
if let PatKind::Tuple(pats, None) = arms[0].pat.kind;
if pats.len() == 1;
then {
let ty = cx.typeck_results().pat_ty(pats[0]).peel_refs();
if *ty.kind() != rustc_middle::ty::Str && !is_type_diagnostic_item(cx, ty, sym::string_type) {
return None;
}
if let ExprKind::Lit(ref lit) = format_args.kind {
if let LitKind::Str(ref s, _) = lit.node {
return Some(format!("{:?}.to_string()", s.as_str()));
}
} else {
let sugg = Sugg::hir(cx, format_args, "<arg>");
if let ExprKind::MethodCall(path, _, _, _) = format_args.kind {
if path.ident.name == sym!(to_string) {
return Some(format!("{}", sugg));
}
} else if let ExprKind::Binary(..) = format_args.kind {
return Some(format!("{}", sugg));
}
return Some(format!("{}.to_string()", sugg.maybe_par()));
}
}
if let ExprKind::Call(_, [_, fmt]) = expr.kind;
if let ExprKind::Path(QPath::Resolved(_, path)) = fmt.kind;
if let [.., t, _] = path.segments;
if t.ident.name.as_str() == "Display";
then { true } else { false }
}
None
}
fn on_new_v1<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) -> Option<String> {
if_chain! {
if let Some(args) = match_function_call(cx, expr, &paths::FMT_ARGUMENTS_NEW_V1);
if args.len() == 2;
// Argument 1 in `new_v1()`
if let ExprKind::AddrOf(BorrowKind::Ref, _, arr) = args[0].kind;
if let ExprKind::Array(pieces) = arr.kind;
if pieces.len() == 1;
if let ExprKind::Lit(ref lit) = pieces[0].kind;
if let LitKind::Str(ref s, _) = lit.node;
// Argument 2 in `new_v1()`
if let ExprKind::AddrOf(BorrowKind::Ref, _, arg1) = args[1].kind;
if let ExprKind::Match(matchee, arms, MatchSource::Normal) = arg1.kind;
if arms.len() == 1;
if let ExprKind::Tup(tup) = matchee.kind;
then {
// `format!("foo")` expansion contains `match () { () => [], }`
if tup.is_empty() {
if let Some(s_src) = snippet_opt(cx, lit.span) {
// Simulate macro expansion, converting {{ and }} to { and }.
let s_expand = s_src.replace("{{", "{").replace("}}", "}");
return Some(format!("{}.to_string()", s_expand));
}
} else if s.as_str().is_empty() {
return on_argumentv1_new(cx, &tup[0], arms);
}
}
}
None
}
fn on_new_v1_fmt<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) -> Option<String> {
if_chain! {
if let Some(args) = match_function_call(cx, expr, &paths::FMT_ARGUMENTS_NEW_V1_FORMATTED);
if args.len() == 3;
if check_unformatted(&args[2]);
// Argument 1 in `new_v1_formatted()`
if let ExprKind::AddrOf(BorrowKind::Ref, _, arr) = args[0].kind;
if let ExprKind::Array(pieces) = arr.kind;
if pieces.len() == 1;
if let ExprKind::Lit(ref lit) = pieces[0].kind;
if let LitKind::Str(symbol, _) = lit.node;
if symbol == kw::Empty;
// Argument 2 in `new_v1_formatted()`
if let ExprKind::AddrOf(BorrowKind::Ref, _, arg1) = args[1].kind;
if let ExprKind::Match(matchee, arms, MatchSource::Normal) = arg1.kind;
if arms.len() == 1;
if let ExprKind::Tup(tup) = matchee.kind;
then {
return on_argumentv1_new(cx, &tup[0], arms);
}
}
None
}
/// Checks if the expression matches
@ -186,10 +131,9 @@ fn on_new_v1_fmt<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) -> Option<S
fn check_unformatted(expr: &Expr<'_>) -> bool {
if_chain! {
if let ExprKind::AddrOf(BorrowKind::Ref, _, expr) = expr.kind;
if let ExprKind::Array(exprs) = expr.kind;
if exprs.len() == 1;
if let ExprKind::Array([expr]) = expr.kind;
// struct `core::fmt::rt::v1::Argument`
if let ExprKind::Struct(_, fields, _) = exprs[0].kind;
if let ExprKind::Struct(_, fields, _) = expr.kind;
if let Some(format_field) = fields.iter().find(|f| f.ident.name == sym::format);
// struct `core::fmt::rt::v1::FormatSpec`
if let ExprKind::Struct(_, fields, _) = format_field.expr.kind;

72
clippy_lints/src/methods/expect_fun_call.rs
View file

@ -1,8 +1,7 @@
use clippy_utils::diagnostics::span_lint_and_sugg;
use clippy_utils::is_expn_of;
use clippy_utils::source::{snippet, snippet_with_applicability};
use clippy_utils::higher::FormatExpn;
use clippy_utils::source::snippet_with_applicability;
use clippy_utils::ty::is_type_diagnostic_item;
use if_chain::if_chain;
use rustc_errors::Applicability;
use rustc_hir as hir;
use rustc_lint::LateContext;
@ -94,27 +93,6 @@ pub(super) fn check(cx: &LateContext<'_>, expr: &hir::Expr<'_>, method_span: Spa
}
}
fn generate_format_arg_snippet(
cx: &LateContext<'_>,
a: &hir::Expr<'_>,
applicability: &mut Applicability,
) -> Vec<String> {
if_chain! {
if let hir::ExprKind::AddrOf(hir::BorrowKind::Ref, _, format_arg) = a.kind;
if let hir::ExprKind::Match(format_arg_expr, _, _) = format_arg.kind;
if let hir::ExprKind::Tup(format_arg_expr_tup) = format_arg_expr.kind;
then {
format_arg_expr_tup
.iter()
.map(|a| snippet_with_applicability(cx, a.span, "..", applicability).into_owned())
.collect()
} else {
unreachable!()
}
}
}
fn is_call(node: &hir::ExprKind<'_>) -> bool {
match node {
hir::ExprKind::AddrOf(hir::BorrowKind::Ref, _, expr) => {
@ -150,36 +128,22 @@ pub(super) fn check(cx: &LateContext<'_>, expr: &hir::Expr<'_>, method_span: Spa
let mut applicability = Applicability::MachineApplicable;
//Special handling for `format!` as arg_root
if_chain! {
if let hir::ExprKind::Block(block, None) = &arg_root.kind;
if block.stmts.len() == 1;
if let hir::StmtKind::Local(local) = &block.stmts[0].kind;
if let Some(arg_root) = &local.init;
if let hir::ExprKind::Call(inner_fun, inner_args) = arg_root.kind;
if is_expn_of(inner_fun.span, "format").is_some() && inner_args.len() == 1;
if let hir::ExprKind::Call(_, format_args) = &inner_args[0].kind;
then {
let fmt_spec = &format_args[0];
let fmt_args = &format_args[1];
let mut args = vec![snippet(cx, fmt_spec.span, "..").into_owned()];
args.extend(generate_format_arg_snippet(cx, fmt_args, &mut applicability));
let sugg = args.join(", ");
span_lint_and_sugg(
cx,
EXPECT_FUN_CALL,
span_replace_word,
&format!("use of `{}` followed by a function call", name),
"try this",
format!("unwrap_or_else({} panic!({}))", closure_args, sugg),
applicability,
);
return;
}
if let Some(format_expn) = FormatExpn::parse(arg_root) {
let span = match *format_expn.format_args.value_args {
[] => format_expn.format_args.format_string_span,
[.., last] => format_expn.format_args.format_string_span.to(last.span),
};
let sugg = snippet_with_applicability(cx, span, "..", &mut applicability);
span_lint_and_sugg(
cx,
EXPECT_FUN_CALL,
span_replace_word,
&format!("use of `{}` followed by a function call", name),
"try this",
format!("unwrap_or_else({} panic!({}))", closure_args, sugg),
applicability,
);
return;
}
let mut arg_root_snippet: Cow<'_, _> = snippet_with_applicability(cx, arg_root.span, "..", &mut applicability);

108
clippy_utils/src/higher.rs
View file

@ -5,11 +5,11 @@
use crate::{is_expn_of, match_def_path, paths};
use if_chain::if_chain;
use rustc_ast::ast;
use rustc_ast::ast::{self, LitKind};
use rustc_hir as hir;
use rustc_hir::{BorrowKind, Expr, ExprKind, StmtKind, UnOp};
use rustc_lint::LateContext;
use rustc_span::source_map::Span;
use rustc_span::{sym, ExpnKind, Span, Symbol};
/// Converts a hir binary operator to the corresponding `ast` type.
#[must_use]
@ -266,3 +266,107 @@ pub fn extract_assert_macro_args<'tcx>(e: &'tcx Expr<'tcx>) -> Option<Vec<&'tcx
}
None
}
/// A parsed `format!` expansion
pub struct FormatExpn<'tcx> {
/// Span of `format!(..)`
pub call_site: Span,
/// Inner `format_args!` expansion
pub format_args: FormatArgsExpn<'tcx>,
}
impl FormatExpn<'tcx> {
/// Parses an expanded `format!` invocation
pub fn parse(expr: &'tcx Expr<'tcx>) -> Option<Self> {
if_chain! {
if let ExprKind::Block(block, _) = expr.kind;
if let [stmt] = block.stmts;
if let StmtKind::Local(local) = stmt.kind;
if let Some(init) = local.init;
if let ExprKind::Call(_, [format_args]) = init.kind;
let expn_data = expr.span.ctxt().outer_expn_data();
if let ExpnKind::Macro { name: sym::format, .. } = expn_data.kind;
if let Some(format_args) = FormatArgsExpn::parse(format_args);
then {
Some(FormatExpn {
call_site: expn_data.call_site,
format_args,
})
} else {
None
}
}
}
}
/// A parsed `format_args!` expansion
pub struct FormatArgsExpn<'tcx> {
/// Span of the first argument, the format string
pub format_string_span: Span,
/// Values passed after the format string
pub value_args: Vec<&'tcx Expr<'tcx>>,
/// String literal expressions which represent the format string split by "{}"
pub format_string_parts: &'tcx [Expr<'tcx>],
/// Symbols corresponding to [`format_string_parts`]
pub format_string_symbols: Vec<Symbol>,
/// Expressions like `ArgumentV1::new(arg0, Debug::fmt)`
pub args: &'tcx [Expr<'tcx>],
/// The final argument passed to `Arguments::new_v1_formatted`, if applicable
pub fmt_expr: Option<&'tcx Expr<'tcx>>,
}
impl FormatArgsExpn<'tcx> {
/// Parses an expanded `format_args!` or `format_args_nl!` invocation
pub fn parse(expr: &'tcx Expr<'tcx>) -> Option<Self> {
if_chain! {
if let ExpnKind::Macro { name, .. } = expr.span.ctxt().outer_expn_data().kind;
let name = name.as_str();
if name.ends_with("format_args") || name.ends_with("format_args_nl");
if let ExprKind::Call(_, args) = expr.kind;
if let Some((strs_ref, args, fmt_expr)) = match args {
// Arguments::new_v1
[strs_ref, args] => Some((strs_ref, args, None)),
// Arguments::new_v1_formatted
[strs_ref, args, fmt_expr] => Some((strs_ref, args, Some(fmt_expr))),
_ => None,
};
if let ExprKind::AddrOf(BorrowKind::Ref, _, strs_arr) = strs_ref.kind;
if let ExprKind::Array(format_string_parts) = strs_arr.kind;
if let Some(format_string_symbols) = format_string_parts
.iter()
.map(|e| {
if let ExprKind::Lit(lit) = &e.kind {
if let LitKind::Str(symbol, _style) = lit.node {
return Some(symbol);
}
}
None
})
.collect();
if let ExprKind::AddrOf(BorrowKind::Ref, _, args) = args.kind;
if let ExprKind::Match(args, [arm], _) = args.kind;
if let ExprKind::Tup(value_args) = args.kind;
if let Some(value_args) = value_args
.iter()
.map(|e| match e.kind {
ExprKind::AddrOf(_, _, e) => Some(e),
_ => None,
})
.collect();
if let ExprKind::Array(args) = arm.body.kind;
then {
Some(FormatArgsExpn {
format_string_span: strs_ref.span,
value_args,
format_string_parts,
format_string_symbols,
args,
fmt_expr,
})
} else {
None
}
}
}
}

4
clippy_utils/src/paths.rs
View file

@ -38,7 +38,6 @@ pub const DEFAULT_TRAIT_METHOD: [&str; 4] = ["core", "default", "Default", "defa
pub const DEREF_MUT_TRAIT_METHOD: [&str; 5] = ["core", "ops", "deref", "DerefMut", "deref_mut"];
pub const DEREF_TRAIT_METHOD: [&str; 5] = ["core", "ops", "deref", "Deref", "deref"];
pub const DIR_BUILDER: [&str; 3] = ["std", "fs", "DirBuilder"];
pub const DISPLAY_FMT_METHOD: [&str; 4] = ["core", "fmt", "Display", "fmt"];
pub const DISPLAY_TRAIT: [&str; 3] = ["core", "fmt", "Display"];
pub const DOUBLE_ENDED_ITERATOR: [&str; 4] = ["core", "iter", "traits", "DoubleEndedIterator"];
pub const DROP: [&str; 3] = ["core", "mem", "drop"];
@ -50,9 +49,6 @@ pub const F32_EPSILON: [&str; 4] = ["core", "f32", "<impl f32>", "EPSILON"];
pub const F64_EPSILON: [&str; 4] = ["core", "f64", "<impl f64>", "EPSILON"];
pub const FILE: [&str; 3] = ["std", "fs", "File"];
pub const FILE_TYPE: [&str; 3] = ["std", "fs", "FileType"];
pub const FMT_ARGUMENTS_NEW_V1: [&str; 4] = ["core", "fmt", "Arguments", "new_v1"];
pub const FMT_ARGUMENTS_NEW_V1_FORMATTED: [&str; 4] = ["core", "fmt", "Arguments", "new_v1_formatted"];
pub const FMT_ARGUMENTV1_NEW: [&str; 4] = ["core", "fmt", "ArgumentV1", "new"];
pub const FROM_FROM: [&str; 4] = ["core", "convert", "From", "from"];
pub const FROM_ITERATOR: [&str; 5] = ["core", "iter", "traits", "collect", "FromIterator"];
pub const FROM_ITERATOR_METHOD: [&str; 6] = ["core", "iter", "traits", "collect", "FromIterator", "from_iter"];