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added code snippet help to match_bool

This commit is contained in:
Andre Bogus 2015-10-21 08:24:56 +02:00
parent 8fdeaa704c
commit da82e2d3ba
2 changed files with 69 additions and 3 deletions
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53
src/matches.rs
View File

@ -1,6 +1,7 @@
use rustc::lint::*;
use rustc_front::hir::*;
use rustc::middle::ty;
use syntax::ast::Lit_::LitBool;
use utils::{snippet, span_lint, span_help_and_lint, in_external_macro, expr_block};
@ -66,10 +67,58 @@ impl LateLintPass for MatchPass {
// check preconditions for MATCH_BOOL
// type of expression == bool
if cx.tcx.expr_ty(ex).sty == ty::TyBool {
span_lint(cx, MATCH_BOOL, expr.span,
if arms.len() == 2 && arms[0].pats.len() == 1 { // no guards
let exprs = if let PatLit(ref arm_bool) = arms[0].pats[0].node {
if let ExprLit(ref lit) = arm_bool.node {
if let LitBool(val) = lit.node {
if val {
Some((&*arms[0].body, &*arms[1].body))
} else {
Some((&*arms[1].body, &*arms[0].body))
}
} else { None }
} else { None }
} else { None };
if let Some((ref true_expr, ref false_expr)) = exprs {
if !is_unit_expr(true_expr) {
if !is_unit_expr(false_expr) {
span_help_and_lint(cx, MATCH_BOOL, expr.span,
"you seem to be trying to match on a boolean expression. \
Consider using an if..else block:",
&format!("try\nif {} {} else {}",
snippet(cx, ex.span, "b"),
expr_block(cx, true_expr, None, ".."),
expr_block(cx, false_expr, None, "..")));
} else {
span_help_and_lint(cx, MATCH_BOOL, expr.span,
"you seem to be trying to match on a boolean expression. \
Consider using an if..else block:",
&format!("try\nif {} {}",
snippet(cx, ex.span, "b"),
expr_block(cx, true_expr, None, "..")));
}
} else if !is_unit_expr(false_expr) {
span_help_and_lint(cx, MATCH_BOOL, expr.span,
"you seem to be trying to match on a boolean expression. \
Consider using an if..else block:",
&format!("try\nif !{} {}",
snippet(cx, ex.span, "b"),
expr_block(cx, false_expr, None, "..")));
} else {
span_lint(cx, MATCH_BOOL, expr.span,
"you seem to be trying to match on a boolean expression. \
Consider using an if..else block");
}
} else {
span_lint(cx, MATCH_BOOL, expr.span,
"you seem to be trying to match on a boolean expression. \
Consider using an if..else block");
}
} else {
span_lint(cx, MATCH_BOOL, expr.span,
"you seem to be trying to match on a boolean expression. \
Consider using an if..else block");
}
}
}
}

19
tests/compile-fail/matches.rs
View File

@ -48,8 +48,25 @@ fn match_bool() {
let option = 1;
match option == 1 { //~ ERROR you seem to be trying to match on a boolean expression
true => 1,
false => 0,
};
match test { //~ ERROR you seem to be trying to match on a boolean expression
true => (),
false => (),
false => { println!("Noooo!"); },
};
match test { //~ ERROR you seem to be trying to match on a boolean expression
//~^ERROR you seem to be trying to use match
//TODO: Remove duplicate warning
false => { println!("Noooo!"); },
_ => (),
};
match test { //~ ERROR you seem to be trying to match on a boolean expression
false => { println!("Noooo!"); },
true => { println!("Yes!"); },
};
// Not linted