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missing match arms diagnostic

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This commit is contained in:
Josh Mcguigan 2020-03-24 04:40:58 -07:00
parent b7e5d94bda
commit 8c378af721
12 changed files with 1048 additions and 11 deletions
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53
crates/ra_hir_ty/src/expr.rs
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@ -14,9 +14,10 @@ use rustc_hash::FxHashSet;
use crate::{
db::HirDatabase,
diagnostics::{MissingFields, MissingOkInTailExpr},
diagnostics::{MissingFields, MissingMatchArms, MissingOkInTailExpr},
utils::variant_data,
ApplicationTy, InferenceResult, Ty, TypeCtor,
_match::{is_useful, MatchCheckCtx, Matrix, PatStack, Usefulness},
};
pub use hir_def::{
@ -52,15 +53,63 @@ impl<'a, 'b> ExprValidator<'a, 'b> {
for e in body.exprs.iter() {
if let (id, Expr::RecordLit { path, fields, spread }) = e {
self.validate_record_literal(id, path, fields, *spread, db);
} else if let (id, Expr::Match { expr, arms }) = e {
self.validate_match(id, *expr, arms, db, self.infer.clone());
}
}
let body_expr = &body[body.body_expr];
if let Expr::Block { statements: _, tail: Some(t) } = body_expr {
if let Expr::Block { tail: Some(t), .. } = body_expr {
self.validate_results_in_tail_expr(body.body_expr, *t, db);
}
}
fn validate_match(
&mut self,
id: ExprId,
expr: ExprId,
arms: &[MatchArm],
db: &dyn HirDatabase,
infer: Arc<InferenceResult>,
) {
let (body, source_map): (Arc<Body>, Arc<BodySourceMap>) =
db.body_with_source_map(self.func.into());
let match_expr: &hir_def::expr::Expr = &body[expr];
let cx = MatchCheckCtx { body: body.clone(), match_expr, infer, db };
let pats = arms.iter().map(|arm| arm.pat);
let mut seen = Matrix::empty();
for pat in pats {
// If we had a NotUsefulMatchArm diagnostic, we could
// check the usefulness of each pattern as we added it
// to the matrix here.
let v = PatStack::from_pattern(pat);
seen.push(&cx, v);
}
match is_useful(&cx, &seen, &PatStack::from_wild()) {
Usefulness::Useful => (),
// if a wildcard pattern is not useful, then all patterns are covered
Usefulness::NotUseful => return,
}
if let Ok(source_ptr) = source_map.expr_syntax(id) {
if let Some(expr) = source_ptr.value.left() {
let root = source_ptr.file_syntax(db.upcast());
if let ast::Expr::MatchExpr(match_expr) = expr.to_node(&root) {
if let Some(arms) = match_expr.match_arm_list() {
self.sink.push(MissingMatchArms {
file: source_ptr.file_id,
arms: AstPtr::new(&arms),
})
}
}
}
}
}
fn validate_record_literal(
&mut self,
id: ExprId,