mod let_unit_value;
+mod unit_arg;
mod unit_cmp;
mod utils;
-use rustc_errors::Applicability;
-use rustc_hir as hir;
-use rustc_hir::{Block, Expr, ExprKind, MatchSource, Node, Stmt, StmtKind};
+use rustc_hir::{Expr, Stmt};
use rustc_lint::{LateContext, LateLintPass};
use rustc_session::{declare_lint_pass, declare_tool_lint};
-use if_chain::if_chain;
-
-use crate::utils::diagnostics::span_lint_and_then;
-use crate::utils::source::{indent_of, reindent_multiline, snippet_opt};
-
-use utils::{is_unit, is_unit_literal};
-
declare_clippy_lint! {
/// **What it does:** Checks for binding a unit value.
///
"comparing unit values"
}
-declare_lint_pass!(UnitTypes => [LET_UNIT_VALUE, UNIT_CMP]);
-
-impl LateLintPass<'_> for UnitTypes {
- fn check_stmt(&mut self, cx: &LateContext<'_>, stmt: &Stmt<'_>) {
- let_unit_value::check(cx, stmt);
- }
-
- fn check_expr(&mut self, cx: &LateContext<'_>, expr: &Expr<'_>) {
- unit_cmp::check(cx, expr);
- }
-}
-
declare_clippy_lint! {
/// **What it does:** Checks for passing a unit value as an argument to a function without using a
/// unit literal (`()`).
"passing unit to a function"
}
-declare_lint_pass!(UnitArg => [UNIT_ARG]);
-
-impl<'tcx> LateLintPass<'tcx> for UnitArg {
- fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
- if expr.span.from_expansion() {
- return;
- }
-
- // apparently stuff in the desugaring of `?` can trigger this
- // so check for that here
- // only the calls to `Try::from_error` is marked as desugared,
- // so we need to check both the current Expr and its parent.
- if is_questionmark_desugar_marked_call(expr) {
- return;
- }
- if_chain! {
- let map = &cx.tcx.hir();
- let opt_parent_node = map.find(map.get_parent_node(expr.hir_id));
- if let Some(hir::Node::Expr(parent_expr)) = opt_parent_node;
- if is_questionmark_desugar_marked_call(parent_expr);
- then {
- return;
- }
- }
-
- match expr.kind {
- ExprKind::Call(_, args) | ExprKind::MethodCall(_, _, args, _) => {
- let args_to_recover = args
- .iter()
- .filter(|arg| {
- if is_unit(cx.typeck_results().expr_ty(arg)) && !is_unit_literal(arg) {
- !matches!(
- &arg.kind,
- ExprKind::Match(.., MatchSource::TryDesugar) | ExprKind::Path(..)
- )
- } else {
- false
- }
- })
- .collect::<Vec<_>>();
- if !args_to_recover.is_empty() {
- lint_unit_args(cx, expr, &args_to_recover);
- }
- },
- _ => (),
- }
- }
-}
+declare_lint_pass!(UnitTypes => [LET_UNIT_VALUE, UNIT_CMP, UNIT_ARG]);
-fn is_questionmark_desugar_marked_call(expr: &Expr<'_>) -> bool {
- use rustc_span::hygiene::DesugaringKind;
- if let ExprKind::Call(ref callee, _) = expr.kind {
- callee.span.is_desugaring(DesugaringKind::QuestionMark)
- } else {
- false
+impl LateLintPass<'_> for UnitTypes {
+ fn check_stmt(&mut self, cx: &LateContext<'_>, stmt: &Stmt<'_>) {
+ let_unit_value::check(cx, stmt);
}
-}
-
-fn lint_unit_args(cx: &LateContext<'_>, expr: &Expr<'_>, args_to_recover: &[&Expr<'_>]) {
- let mut applicability = Applicability::MachineApplicable;
- let (singular, plural) = if args_to_recover.len() > 1 {
- ("", "s")
- } else {
- ("a ", "")
- };
- span_lint_and_then(
- cx,
- UNIT_ARG,
- expr.span,
- &format!("passing {}unit value{} to a function", singular, plural),
- |db| {
- let mut or = "";
- args_to_recover
- .iter()
- .filter_map(|arg| {
- if_chain! {
- if let ExprKind::Block(block, _) = arg.kind;
- if block.expr.is_none();
- if let Some(last_stmt) = block.stmts.iter().last();
- if let StmtKind::Semi(last_expr) = last_stmt.kind;
- if let Some(snip) = snippet_opt(cx, last_expr.span);
- then {
- Some((
- last_stmt.span,
- snip,
- ))
- }
- else {
- None
- }
- }
- })
- .for_each(|(span, sugg)| {
- db.span_suggestion(
- span,
- "remove the semicolon from the last statement in the block",
- sugg,
- Applicability::MaybeIncorrect,
- );
- or = "or ";
- applicability = Applicability::MaybeIncorrect;
- });
-
- let arg_snippets: Vec<String> = args_to_recover
- .iter()
- .filter_map(|arg| snippet_opt(cx, arg.span))
- .collect();
- let arg_snippets_without_empty_blocks: Vec<String> = args_to_recover
- .iter()
- .filter(|arg| !is_empty_block(arg))
- .filter_map(|arg| snippet_opt(cx, arg.span))
- .collect();
-
- if let Some(call_snippet) = snippet_opt(cx, expr.span) {
- let sugg = fmt_stmts_and_call(
- cx,
- expr,
- &call_snippet,
- &arg_snippets,
- &arg_snippets_without_empty_blocks,
- );
- if arg_snippets_without_empty_blocks.is_empty() {
- db.multipart_suggestion(
- &format!("use {}unit literal{} instead", singular, plural),
- args_to_recover
- .iter()
- .map(|arg| (arg.span, "()".to_string()))
- .collect::<Vec<_>>(),
- applicability,
- );
- } else {
- let plural = arg_snippets_without_empty_blocks.len() > 1;
- let empty_or_s = if plural { "s" } else { "" };
- let it_or_them = if plural { "them" } else { "it" };
- db.span_suggestion(
- expr.span,
- &format!(
- "{}move the expression{} in front of the call and replace {} with the unit literal `()`",
- or, empty_or_s, it_or_them
- ),
- sugg,
- applicability,
- );
- }
- }
- },
- );
-}
-
-fn is_empty_block(expr: &Expr<'_>) -> bool {
- matches!(
- expr.kind,
- ExprKind::Block(
- Block {
- stmts: &[],
- expr: None,
- ..
- },
- _,
- )
- )
-}
-
-fn fmt_stmts_and_call(
- cx: &LateContext<'_>,
- call_expr: &Expr<'_>,
- call_snippet: &str,
- args_snippets: &[impl AsRef<str>],
- non_empty_block_args_snippets: &[impl AsRef<str>],
-) -> String {
- let call_expr_indent = indent_of(cx, call_expr.span).unwrap_or(0);
- let call_snippet_with_replacements = args_snippets
- .iter()
- .fold(call_snippet.to_owned(), |acc, arg| acc.replacen(arg.as_ref(), "()", 1));
-
- let mut stmts_and_call = non_empty_block_args_snippets
- .iter()
- .map(|it| it.as_ref().to_owned())
- .collect::<Vec<_>>();
- stmts_and_call.push(call_snippet_with_replacements);
- stmts_and_call = stmts_and_call
- .into_iter()
- .map(|v| reindent_multiline(v.into(), true, Some(call_expr_indent)).into_owned())
- .collect();
-
- let mut stmts_and_call_snippet = stmts_and_call.join(&format!("{}{}", ";\n", " ".repeat(call_expr_indent)));
- // expr is not in a block statement or result expression position, wrap in a block
- let parent_node = cx.tcx.hir().find(cx.tcx.hir().get_parent_node(call_expr.hir_id));
- if !matches!(parent_node, Some(Node::Block(_))) && !matches!(parent_node, Some(Node::Stmt(_))) {
- let block_indent = call_expr_indent + 4;
- stmts_and_call_snippet =
- reindent_multiline(stmts_and_call_snippet.into(), true, Some(block_indent)).into_owned();
- stmts_and_call_snippet = format!(
- "{{\n{}{}\n{}}}",
- " ".repeat(block_indent),
- &stmts_and_call_snippet,
- " ".repeat(call_expr_indent)
- );
+ fn check_expr(&mut self, cx: &LateContext<'_>, expr: &Expr<'_>) {
+ unit_cmp::check(cx, expr);
+ unit_arg::check(cx, expr);
}
- stmts_and_call_snippet
}
--- /dev/null
+use rustc_errors::Applicability;
+use rustc_hir::{self as hir, Block, Expr, ExprKind, MatchSource, Node, StmtKind};
+use rustc_lint::LateContext;
+
+use if_chain::if_chain;
+
+use crate::utils::diagnostics::span_lint_and_then;
+use crate::utils::source::{indent_of, reindent_multiline, snippet_opt};
+
+use super::{utils, UNIT_ARG};
+
+pub(super) fn check(cx: &LateContext<'_>, expr: &Expr<'_>) {
+ if expr.span.from_expansion() {
+ return;
+ }
+
+ // apparently stuff in the desugaring of `?` can trigger this
+ // so check for that here
+ // only the calls to `Try::from_error` is marked as desugared,
+ // so we need to check both the current Expr and its parent.
+ if is_questionmark_desugar_marked_call(expr) {
+ return;
+ }
+ if_chain! {
+ let map = &cx.tcx.hir();
+ let opt_parent_node = map.find(map.get_parent_node(expr.hir_id));
+ if let Some(hir::Node::Expr(parent_expr)) = opt_parent_node;
+ if is_questionmark_desugar_marked_call(parent_expr);
+ then {
+ return;
+ }
+ }
+
+ match expr.kind {
+ ExprKind::Call(_, args) | ExprKind::MethodCall(_, _, args, _) => {
+ let args_to_recover = args
+ .iter()
+ .filter(|arg| {
+ if utils::is_unit(cx.typeck_results().expr_ty(arg)) && !utils::is_unit_literal(arg) {
+ !matches!(
+ &arg.kind,
+ ExprKind::Match(.., MatchSource::TryDesugar) | ExprKind::Path(..)
+ )
+ } else {
+ false
+ }
+ })
+ .collect::<Vec<_>>();
+ if !args_to_recover.is_empty() {
+ lint_unit_args(cx, expr, &args_to_recover);
+ }
+ },
+ _ => (),
+ }
+}
+
+fn is_questionmark_desugar_marked_call(expr: &Expr<'_>) -> bool {
+ use rustc_span::hygiene::DesugaringKind;
+ if let ExprKind::Call(ref callee, _) = expr.kind {
+ callee.span.is_desugaring(DesugaringKind::QuestionMark)
+ } else {
+ false
+ }
+}
+
+fn lint_unit_args(cx: &LateContext<'_>, expr: &Expr<'_>, args_to_recover: &[&Expr<'_>]) {
+ let mut applicability = Applicability::MachineApplicable;
+ let (singular, plural) = if args_to_recover.len() > 1 {
+ ("", "s")
+ } else {
+ ("a ", "")
+ };
+ span_lint_and_then(
+ cx,
+ UNIT_ARG,
+ expr.span,
+ &format!("passing {}unit value{} to a function", singular, plural),
+ |db| {
+ let mut or = "";
+ args_to_recover
+ .iter()
+ .filter_map(|arg| {
+ if_chain! {
+ if let ExprKind::Block(block, _) = arg.kind;
+ if block.expr.is_none();
+ if let Some(last_stmt) = block.stmts.iter().last();
+ if let StmtKind::Semi(last_expr) = last_stmt.kind;
+ if let Some(snip) = snippet_opt(cx, last_expr.span);
+ then {
+ Some((
+ last_stmt.span,
+ snip,
+ ))
+ }
+ else {
+ None
+ }
+ }
+ })
+ .for_each(|(span, sugg)| {
+ db.span_suggestion(
+ span,
+ "remove the semicolon from the last statement in the block",
+ sugg,
+ Applicability::MaybeIncorrect,
+ );
+ or = "or ";
+ applicability = Applicability::MaybeIncorrect;
+ });
+
+ let arg_snippets: Vec<String> = args_to_recover
+ .iter()
+ .filter_map(|arg| snippet_opt(cx, arg.span))
+ .collect();
+ let arg_snippets_without_empty_blocks: Vec<String> = args_to_recover
+ .iter()
+ .filter(|arg| !is_empty_block(arg))
+ .filter_map(|arg| snippet_opt(cx, arg.span))
+ .collect();
+
+ if let Some(call_snippet) = snippet_opt(cx, expr.span) {
+ let sugg = fmt_stmts_and_call(
+ cx,
+ expr,
+ &call_snippet,
+ &arg_snippets,
+ &arg_snippets_without_empty_blocks,
+ );
+
+ if arg_snippets_without_empty_blocks.is_empty() {
+ db.multipart_suggestion(
+ &format!("use {}unit literal{} instead", singular, plural),
+ args_to_recover
+ .iter()
+ .map(|arg| (arg.span, "()".to_string()))
+ .collect::<Vec<_>>(),
+ applicability,
+ );
+ } else {
+ let plural = arg_snippets_without_empty_blocks.len() > 1;
+ let empty_or_s = if plural { "s" } else { "" };
+ let it_or_them = if plural { "them" } else { "it" };
+ db.span_suggestion(
+ expr.span,
+ &format!(
+ "{}move the expression{} in front of the call and replace {} with the unit literal `()`",
+ or, empty_or_s, it_or_them
+ ),
+ sugg,
+ applicability,
+ );
+ }
+ }
+ },
+ );
+}
+
+fn is_empty_block(expr: &Expr<'_>) -> bool {
+ matches!(
+ expr.kind,
+ ExprKind::Block(
+ Block {
+ stmts: &[],
+ expr: None,
+ ..
+ },
+ _,
+ )
+ )
+}
+
+fn fmt_stmts_and_call(
+ cx: &LateContext<'_>,
+ call_expr: &Expr<'_>,
+ call_snippet: &str,
+ args_snippets: &[impl AsRef<str>],
+ non_empty_block_args_snippets: &[impl AsRef<str>],
+) -> String {
+ let call_expr_indent = indent_of(cx, call_expr.span).unwrap_or(0);
+ let call_snippet_with_replacements = args_snippets
+ .iter()
+ .fold(call_snippet.to_owned(), |acc, arg| acc.replacen(arg.as_ref(), "()", 1));
+
+ let mut stmts_and_call = non_empty_block_args_snippets
+ .iter()
+ .map(|it| it.as_ref().to_owned())
+ .collect::<Vec<_>>();
+ stmts_and_call.push(call_snippet_with_replacements);
+ stmts_and_call = stmts_and_call
+ .into_iter()
+ .map(|v| reindent_multiline(v.into(), true, Some(call_expr_indent)).into_owned())
+ .collect();
+
+ let mut stmts_and_call_snippet = stmts_and_call.join(&format!("{}{}", ";\n", " ".repeat(call_expr_indent)));
+ // expr is not in a block statement or result expression position, wrap in a block
+ let parent_node = cx.tcx.hir().find(cx.tcx.hir().get_parent_node(call_expr.hir_id));
+ if !matches!(parent_node, Some(Node::Block(_))) && !matches!(parent_node, Some(Node::Stmt(_))) {
+ let block_indent = call_expr_indent + 4;
+ stmts_and_call_snippet =
+ reindent_multiline(stmts_and_call_snippet.into(), true, Some(block_indent)).into_owned();
+ stmts_and_call_snippet = format!(
+ "{{\n{}{}\n{}}}",
+ " ".repeat(block_indent),
+ &stmts_and_call_snippet,
+ " ".repeat(call_expr_indent)
+ );
+ }
+ stmts_and_call_snippet
+}
projects / rust.git / commitdiff