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Merge pull request #275 from Manishearth/shadow

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extended pattern matching
This commit is contained in:
llogiq 2015-09-02 08:56:12 +02:00
commit 2086f97bbd
4 changed files with 88 additions and 32 deletions
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81
src/shadow.rs
View File

@ -6,7 +6,7 @@ use syntax::visit::FnKind;
use rustc::lint::{Context, LintArray, LintPass};
use rustc::middle::def::Def::{DefVariant, DefStruct};
use utils::{in_external_macro, snippet, span_lint};
use utils::{in_external_macro, snippet, span_lint, span_note_and_lint};
declare_lint!(pub SHADOW_SAME, Allow,
"rebinding a name to itself, e.g. `let mut x = &mut x`");
@ -60,8 +60,12 @@ fn check_decl(cx: &Context, decl: &Decl, bindings: &mut Vec<Name>) {
if let DeclLocal(ref local) = decl.node {
let Local{ ref pat, ref ty, ref init, id: _, span } = **local;
if let &Some(ref t) = ty { check_ty(cx, t, bindings) }
if let &Some(ref o) = init { check_expr(cx, o, bindings) }
check_pat(cx, pat, init, span, bindings);
if let &Some(ref o) = init {
check_expr(cx, o, bindings);
check_pat(cx, pat, &Some(o), span, bindings);
} else {
check_pat(cx, pat, &None, span, bindings);
}
}
}
@ -72,8 +76,8 @@ fn is_binding(cx: &Context, pat: &Pat) -> bool {
}
}
fn check_pat<T>(cx: &Context, pat: &Pat, init: &Option<T>, span: Span,
bindings: &mut Vec<Name>) where T: Deref<Target=Expr> {
fn check_pat(cx: &Context, pat: &Pat, init: &Option<&Expr>, span: Span,
bindings: &mut Vec<Name>) {
//TODO: match more stuff / destructuring
match pat.node {
PatIdent(_, ref ident, ref inner) => {
@ -88,22 +92,55 @@ fn check_pat<T>(cx: &Context, pat: &Pat, init: &Option<T>, span: Span,
if let Some(ref p) = *inner { check_pat(cx, p, init, span, bindings); }
},
//PatEnum(Path, Option<Vec<P<Pat>>>),
//PatQPath(QSelf, Path),
//PatStruct(Path, Vec<Spanned<FieldPat>>, bool),
//PatTup(Vec<P<Pat>>),
PatStruct(_, ref pfields, _) =>
if let Some(ref init_struct) = *init {
if let ExprStruct(_, ref efields, _) = init_struct.node {
for field in pfields {
let ident = field.node.ident;
let efield = efields.iter()
.find(|ref f| f.ident.node == ident)
.map(|f| &*f.expr);
check_pat(cx, &field.node.pat, &efield, span, bindings);
}
} else {
for field in pfields {
check_pat(cx, &field.node.pat, init, span, bindings);
}
}
} else {
for field in pfields {
check_pat(cx, &field.node.pat, &None, span, bindings);
}
},
PatTup(ref inner) =>
if let Some(ref init_tup) = *init {
if let ExprTup(ref tup) = init_tup.node {
for (i, p) in inner.iter().enumerate() {
check_pat(cx, p, &Some(&tup[i]), p.span, bindings);
}
} else {
for p in inner {
check_pat(cx, p, init, span, bindings);
}
}
} else {
for p in inner {
check_pat(cx, p, &None, span, bindings);
}
},
PatBox(ref inner) => {
if let Some(ref initp) = *init {
match initp.node {
ExprBox(_, ref inner_init) =>
check_pat(cx, inner, &Some(&**inner_init), span, bindings),
//TODO: ExprCall on Box::new
_ => check_pat(cx, inner, init, span, bindings),
if let ExprBox(_, ref inner_init) = initp.node {
check_pat(cx, inner, &Some(&**inner_init), span, bindings);
} else {
check_pat(cx, inner, init, span, bindings);
}
} else {
check_pat(cx, inner, init, span, bindings);
}
},
//PatRegion(P<Pat>, Mutability),
PatRegion(ref inner, _) =>
check_pat(cx, inner, init, span, bindings),
//PatRange(P<Expr>, P<Expr>),
//PatVec(Vec<P<Pat>>, Option<P<Pat>>, Vec<P<Pat>>),
_ => (),
@ -112,7 +149,7 @@ fn check_pat<T>(cx: &Context, pat: &Pat, init: &Option<T>, span: Span,
fn lint_shadow<T>(cx: &Context, name: Name, span: Span, lspan: Span, init:
&Option<T>) where T: Deref<Target=Expr> {
if let &Some(ref expr) = init {
if let Some(ref expr) = *init {
if is_self_shadow(name, expr) {
span_lint(cx, SHADOW_SAME, span, &format!(
"{} is shadowed by itself in {}",
@ -120,20 +157,22 @@ fn lint_shadow<T>(cx: &Context, name: Name, span: Span, lspan: Span, init:
snippet(cx, expr.span, "..")));
} else {
if contains_self(name, expr) {
span_lint(cx, SHADOW_REUSE, span, &format!(
span_note_and_lint(cx, SHADOW_REUSE, lspan, &format!(
"{} is shadowed by {} which reuses the original value",
snippet(cx, lspan, "_"),
snippet(cx, expr.span, "..")));
snippet(cx, expr.span, "..")),
expr.span, "initialization happens here");
} else {
span_lint(cx, SHADOW_UNRELATED, span, &format!(
"{} is shadowed by {} in this declaration",
span_note_and_lint(cx, SHADOW_UNRELATED, lspan, &format!(
"{} is shadowed by {}",
snippet(cx, lspan, "_"),
snippet(cx, expr.span, "..")));
snippet(cx, expr.span, "..")),
expr.span, "initialization happens here");
}
}
} else {
span_lint(cx, SHADOW_UNRELATED, span, &format!(
"{} is shadowed in this declaration", snippet(cx, lspan, "_")));
"{} shadows a previous declaration", snippet(cx, lspan, "_")));
}
}

17
src/utils.rs
View File

@ -177,7 +177,7 @@ pub fn span_lint(cx: &Context, lint: &'static Lint, sp: Span, msg: &str) {
pub fn span_help_and_lint(cx: &Context, lint: &'static Lint, span: Span,
msg: &str, help: &str) {
span_lint(cx, lint, span, msg);
cx.span_lint(lint, span, msg);
if cx.current_level(lint) != Level::Allow {
cx.sess().fileline_help(span, &format!("{}\nfor further information \
visit https://github.com/Manishearth/rust-clippy/wiki#{}",
@ -185,6 +185,21 @@ pub fn span_help_and_lint(cx: &Context, lint: &'static Lint, span: Span,
}
}
pub fn span_note_and_lint(cx: &Context, lint: &'static Lint, span: Span,
msg: &str, note_span: Span, note: &str) {
cx.span_lint(lint, span, msg);
if cx.current_level(lint) != Level::Allow {
if note_span == span {
cx.sess().fileline_note(note_span, note)
} else {
cx.sess().span_note(note_span, note)
}
cx.sess().fileline_help(span, &format!("for further information visit \
https://github.com/Manishearth/rust-clippy/wiki#{}",
lint.name_lower()))
}
}
/// return the base type for references and raw pointers
pub fn walk_ptrs_ty(ty: ty::Ty) -> ty::Ty {
match ty.sty {

2
tests/compile-fail/matches.rs
View File

@ -39,6 +39,7 @@ fn single_match(){
}
fn ref_pats() {
{
let ref v = Some(0);
match v { //~ERROR instead of prefixing all patterns with `&`
&Some(v) => println!("{:?}", v),
@ -48,6 +49,7 @@ fn ref_pats() {
&Some(v) => println!("some"),
other => println!("other"),
}
}
let ref tup = (1, 2);
match tup { //~ERROR instead of prefixing all patterns with `&`
&(v, 1) => println!("{}", v),

2
tests/compile-fail/shadow.rs
View File

@ -18,7 +18,7 @@ fn main() {
let x = (1, x); //~ERROR: x is shadowed by (1, x) which reuses
let x = first(x); //~ERROR: x is shadowed by first(x) which reuses
let y = 1;
let x = y; //~ERROR: x is shadowed by y in this declaration
let x = y; //~ERROR: x is shadowed by y
let o = Some(1u8);