-use clippy_utils::diagnostics::{span_lint_and_help, span_lint_and_sugg};
+use clippy_utils::diagnostics::span_lint_and_sugg;
use clippy_utils::macros::FormatArgsExpn;
+use clippy_utils::source::snippet_with_applicability;
use clippy_utils::{is_expn_of, match_function_call, paths};
use if_chain::if_chain;
use rustc_errors::Applicability;
-use rustc_hir::{Expr, ExprKind};
+use rustc_hir::def::Res;
+use rustc_hir::{BindingAnnotation, Block, BlockCheckMode, Expr, ExprKind, Node, PatKind, QPath, Stmt, StmtKind};
use rustc_lint::{LateContext, LateLintPass};
use rustc_session::{declare_lint_pass, declare_tool_lint};
use rustc_span::sym;
/// ```rust
/// # use std::io::Write;
/// # let bar = "furchtbar";
- /// // this would be clearer as `eprintln!("foo: {:?}", bar);`
/// writeln!(&mut std::io::stderr(), "foo: {:?}", bar).unwrap();
+ /// writeln!(&mut std::io::stdout(), "foo: {:?}", bar).unwrap();
+ /// ```
+ ///
+ /// Use instead:
+ /// ```rust
+ /// # use std::io::Write;
+ /// # let bar = "furchtbar";
+ /// eprintln!("foo: {:?}", bar);
+ /// println!("foo: {:?}", bar);
/// ```
#[clippy::version = "pre 1.29.0"]
pub EXPLICIT_WRITE,
fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
if_chain! {
// match call to unwrap
- if let ExprKind::MethodCall(unwrap_fun, _, [write_call], _) = 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 let ExprKind::MethodCall(write_fun, _, [write_recv, write_arg], _) = write_call.kind;
+ if let ExprKind::MethodCall(write_fun, [write_recv, write_arg], _) = look_in_block(cx, &write_call.kind);
if write_fun.ident.name == sym!(write_fmt);
// match calls to std::io::stdout() / std::io::stderr ()
if let Some(dest_name) = if match_function_call(cx, write_recv, &paths::STDOUT).is_some() {
"print".into(),
)
};
- let msg = format!("use of `{}.unwrap()`", used);
- if let [write_output] = *format_args.format_string_parts {
- let mut write_output = write_output.to_string();
- if write_output.ends_with('\n') {
- write_output.pop();
- }
-
- let sugg = format!("{}{}!(\"{}\")", prefix, sugg_mac, write_output.escape_default());
- span_lint_and_sugg(
- cx,
- EXPLICIT_WRITE,
- expr.span,
- &msg,
- "try this",
- sugg,
- Applicability::MachineApplicable
- );
- } else {
- // We don't have a proper suggestion
- let help = format!("consider using `{}{}!` instead", prefix, sugg_mac);
- span_lint_and_help(cx, EXPLICIT_WRITE, expr.span, &msg, None, &help);
- }
+ let mut applicability = Applicability::MachineApplicable;
+ let inputs_snippet = snippet_with_applicability(
+ cx,
+ format_args.inputs_span(),
+ "..",
+ &mut applicability,
+ );
+ span_lint_and_sugg(
+ cx,
+ EXPLICIT_WRITE,
+ expr.span,
+ &format!("use of `{}.unwrap()`", used),
+ "try this",
+ format!("{}{}!({})", prefix, sugg_mac, inputs_snippet),
+ applicability,
+ )
}
}
}
}
+
+/// If `kind` is a block that looks like `{ let result = $expr; result }` then
+/// returns $expr. Otherwise returns `kind`.
+fn look_in_block<'tcx, 'hir>(cx: &LateContext<'tcx>, kind: &'tcx ExprKind<'hir>) -> &'tcx ExprKind<'hir> {
+ if_chain! {
+ if let ExprKind::Block(block, _label @ None) = kind;
+ if let Block {
+ stmts: [Stmt { kind: StmtKind::Local(local), .. }],
+ expr: Some(expr_end_of_block),
+ rules: BlockCheckMode::DefaultBlock,
+ ..
+ } = block;
+
+ // Find id of the local that expr_end_of_block resolves to
+ if let ExprKind::Path(QPath::Resolved(None, expr_path)) = expr_end_of_block.kind;
+ if let Res::Local(expr_res) = expr_path.res;
+ if let Some(Node::Pat(res_pat)) = cx.tcx.hir().find(expr_res);
+
+ // Find id of the local we found in the block
+ if let PatKind::Binding(BindingAnnotation::Unannotated, local_hir_id, _ident, None) = local.pat.kind;
+
+ // If those two are the same hir id
+ if res_pat.hir_id == local_hir_id;
+
+ if let Some(init) = local.init;
+ then {
+ return &init.kind;
+ }
+ }
+ kind
+}