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//! FIXME: write short doc here
use std::sync::Arc;
use hir_def::{path::path, resolver::HasResolver, AdtId, FunctionId};
use hir_expand::diagnostics::DiagnosticSink;
use ra_syntax::{ast, AstPtr};
use rustc_hash::FxHashSet;
use crate::{
db::HirDatabase,
diagnostics::{MissingFields, MissingMatchArms, MissingOkInTailExpr},
utils::variant_data,
ApplicationTy, InferenceResult, Ty, TypeCtor,
_match::{is_useful, MatchCheckCtx, Matrix, PatStack, Usefulness},
};
pub use hir_def::{
body::{
scope::{ExprScopes, ScopeEntry, ScopeId},
Body, BodySourceMap, ExprPtr, ExprSource, PatPtr, PatSource,
},
expr::{
ArithOp, Array, BinaryOp, BindingAnnotation, CmpOp, Expr, ExprId, Literal, LogicOp,
MatchArm, Ordering, Pat, PatId, RecordFieldPat, RecordLitField, Statement, UnaryOp,
},
LocalStructFieldId, VariantId,
};
pub struct ExprValidator<'a, 'b: 'a> {
func: FunctionId,
infer: Arc<InferenceResult>,
sink: &'a mut DiagnosticSink<'b>,
}
impl<'a, 'b> ExprValidator<'a, 'b> {
pub fn new(
func: FunctionId,
infer: Arc<InferenceResult>,
sink: &'a mut DiagnosticSink<'b>,
) -> ExprValidator<'a, 'b> {
ExprValidator { func, infer, sink }
}
pub fn validate_body(&mut self, db: &dyn HirDatabase) {
let body = db.body(self.func.into());
for (id, expr) in body.exprs.iter() {
if let Some((variant_def, missed_fields, true)) =
record_literal_missing_fields(db, &self.infer, id, expr)
{
// XXX: only look at source_map if we do have missing fields
let (_, source_map) = db.body_with_source_map(self.func.into());
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::RecordLit(record_lit) = expr.to_node(&root) {
if let Some(field_list) = record_lit.record_field_list() {
let variant_data = variant_data(db.upcast(), variant_def);
let missed_fields = missed_fields
.into_iter()
.map(|idx| variant_data.fields()[idx].name.clone())
.collect();
self.sink.push(MissingFields {
file: source_ptr.file_id,
field_list: AstPtr::new(&field_list),
missed_fields,
})
}
}
}
}
}
if let Expr::Match { expr, arms } = expr {
self.validate_match(id, *expr, arms, db, self.infer.clone());
}
}
let body_expr = &body[body.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,
match_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_ty = match infer.type_of_expr.get(match_expr) {
Some(ty) => ty,
// If we can't resolve the type of the match expression
// we cannot perform exhaustiveness checks.
None => return,
};
let cx = MatchCheckCtx { body, infer: infer.clone(), db };
let pats = arms.iter().map(|arm| arm.pat);
let mut seen = Matrix::empty();
for pat in pats {
// We skip any patterns whose type we cannot resolve.
//
// This could lead to false positives in this diagnostic, so
// it might be better to skip the entire diagnostic if we either
// cannot resolve a match arm or determine that the match arm has
// the wrong type.
if let Some(pat_ty) = infer.type_of_pat.get(pat) {
// We only include patterns whose type matches the type
// of the match expression. If we had a InvalidMatchArmPattern
// diagnostic or similar we could raise that in an else
// block here.
//
// When comparing the types, we also have to consider that rustc
// will automatically de-reference the match expression type if
// necessary.
//
// FIXME we should use the type checker for this.
if pat_ty == match_expr_ty
|| match_expr_ty
.as_reference()
.map(|(match_expr_ty, _)| match_expr_ty == pat_ty)
.unwrap_or(false)
{
// 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()) {
Ok(Usefulness::Useful) => (),
// if a wildcard pattern is not useful, then all patterns are covered
Ok(Usefulness::NotUseful) => return,
// this path is for unimplemented checks, so we err on the side of not
// reporting any errors
_ => 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(match_expr), Some(arms)) =
(match_expr.expr(), match_expr.match_arm_list())
{
self.sink.push(MissingMatchArms {
file: source_ptr.file_id,
match_expr: AstPtr::new(&match_expr),
arms: AstPtr::new(&arms),
})
}
}
}
}
}
fn validate_results_in_tail_expr(&mut self, body_id: ExprId, id: ExprId, db: &dyn HirDatabase) {
// the mismatch will be on the whole block currently
let mismatch = match self.infer.type_mismatch_for_expr(body_id) {
Some(m) => m,
None => return,
};
let std_result_path = path![std::result::Result];
let resolver = self.func.resolver(db.upcast());
let std_result_enum = match resolver.resolve_known_enum(db.upcast(), &std_result_path) {
Some(it) => it,
_ => return,
};
let std_result_ctor = TypeCtor::Adt(AdtId::EnumId(std_result_enum));
let params = match &mismatch.expected {
Ty::Apply(ApplicationTy { ctor, parameters }) if ctor == &std_result_ctor => parameters,
_ => return,
};
if params.len() == 2 && params[0] == mismatch.actual {
let (_, source_map) = db.body_with_source_map(self.func.into());
if let Ok(source_ptr) = source_map.expr_syntax(id) {
if let Some(expr) = source_ptr.value.left() {
self.sink.push(MissingOkInTailExpr { file: source_ptr.file_id, expr });
}
}
}
}
}
pub fn record_literal_missing_fields(
db: &dyn HirDatabase,
infer: &InferenceResult,
id: ExprId,
expr: &Expr,
) -> Option<(VariantId, Vec<LocalStructFieldId>, /*exhaustive*/ bool)> {
let (fields, exhausitve) = match expr {
Expr::RecordLit { path: _, fields, spread } => (fields, spread.is_none()),
_ => return None,
};
let variant_def = infer.variant_resolution_for_expr(id)?;
if let VariantId::UnionId(_) = variant_def {
return None;
}
let variant_data = variant_data(db.upcast(), variant_def);
let specified_fields: FxHashSet<_> = fields.iter().map(|f| &f.name).collect();
let missed_fields: Vec<LocalStructFieldId> = variant_data
.fields()
.iter()
.filter_map(|(f, d)| if specified_fields.contains(&d.name) { None } else { Some(f) })
.collect();
if missed_fields.is_empty() {
return None;
}
Some((variant_def, missed_fields, exhausitve))
}
pub fn record_pattern_missing_fields(
db: &dyn HirDatabase,
infer: &InferenceResult,
id: PatId,
pat: &Pat,
) -> Option<(VariantId, Vec<LocalStructFieldId>)> {
let fields = match pat {
Pat::Record { path: _, args } => args,
_ => return None,
};
let variant_def = infer.variant_resolution_for_pat(id)?;
if let VariantId::UnionId(_) = variant_def {
return None;
}
let variant_data = variant_data(db.upcast(), variant_def);
let specified_fields: FxHashSet<_> = fields.iter().map(|f| &f.name).collect();
let missed_fields: Vec<LocalStructFieldId> = variant_data
.fields()
.iter()
.filter_map(|(f, d)| if specified_fields.contains(&d.name) { None } else { Some(f) })
.collect();
if missed_fields.is_empty() {
return None;
}
Some((variant_def, missed_fields))
}
|
