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Fix wrong suggestion for redundant_closure_call

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Fixes #1684
This commit is contained in:
Michael Wright 2018-11-14 08:01:39 +02:00
parent 6cc502dda0
commit e2e892b59b
2 changed files with 50 additions and 16 deletions
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61
clippy_lints/src/misc_early.rs
View File

@ -15,7 +15,7 @@ use if_chain::if_chain;
use std::char;
use crate::syntax::ast::*;
use crate::syntax::source_map::Span;
use crate::syntax::visit::FnKind;
use crate::syntax::visit::{FnKind, Visitor, walk_expr};
use crate::utils::{constants, snippet, snippet_opt, span_help_and_lint, span_lint, span_lint_and_then};
use crate::rustc_errors::Applicability;
@ -199,6 +199,31 @@ impl LintPass for MiscEarly {
}
}
// Used to find `return` statements or equivalents e.g. `?`
struct ReturnVisitor {
found_return: bool,
}
impl ReturnVisitor {
fn new() -> ReturnVisitor {
ReturnVisitor {
found_return: false,
}
}
}
impl<'ast> Visitor<'ast> for ReturnVisitor {
fn visit_expr(&mut self, ex: &'ast Expr) {
if let ExprKind::Ret(_) = ex.node {
self.found_return = true;
} else if let ExprKind::Try(_) = ex.node {
self.found_return = true;
}
walk_expr(self, ex)
}
}
impl EarlyLintPass for MiscEarly {
fn check_generics(&mut self, cx: &EarlyContext<'_>, gen: &Generics) {
for param in &gen.params {
@ -311,21 +336,25 @@ impl EarlyLintPass for MiscEarly {
match expr.node {
ExprKind::Call(ref paren, _) => if let ExprKind::Paren(ref closure) = paren.node {
if let ExprKind::Closure(_, _, _, ref decl, ref block, _) = closure.node {
span_lint_and_then(
cx,
REDUNDANT_CLOSURE_CALL,
expr.span,
"Try not to call a closure in the expression where it is declared.",
|db| if decl.inputs.is_empty() {
let hint = snippet(cx, block.span, "..").into_owned();
db.span_suggestion_with_applicability(
expr.span,
"Try doing something like: ",
hint,
Applicability::MachineApplicable, // snippet
);
},
);
let mut visitor = ReturnVisitor::new();
visitor.visit_expr(block);
if !visitor.found_return {
span_lint_and_then(
cx,
REDUNDANT_CLOSURE_CALL,
expr.span,
"Try not to call a closure in the expression where it is declared.",
|db| if decl.inputs.is_empty() {
let hint = snippet(cx, block.span, "..").into_owned();
db.span_suggestion_with_applicability(
expr.span,
"Try doing something like: ",
hint,
Applicability::MachineApplicable, // snippet
);
},
);
}
}
},
ExprKind::Unary(UnOp::Neg, ref inner) => if let ExprKind::Unary(UnOp::Neg, _) = inner.node {

5
tests/ui/redundant_closure_call.rs
View File

@ -28,4 +28,9 @@ fn main() {
i = closure(3);
i = closure(4);
#[allow(clippy::needless_return)]
(|| return 2)();
(|| -> Option<i32> { None? })();
(|| -> Result<i32, i32> { r#try!(Err(2)) })();
}