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match arm
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@Medowhill
Medowhill committed May 28, 2024
1 parent 1e1e9e2 commit a24c58c
Showing 1 changed file with 95 additions and 56 deletions.
151 changes: 95 additions & 56 deletions src/tag_analysis.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -410,6 +410,10 @@ pub fn analyze(tcx: TyCtxt<'_>, conf: &Config) {
let ItemKind::Union(VariantData::Struct(fs, _), _) = item.kind else { unreachable!() };
let field_names: IndexVec<FieldIdx, _> =
fs.iter().map(|f| f.ident.name.to_ident_string()).collect();
let field_tys: IndexVec<FieldIdx, _> = fs
.iter()
.map(|f| source_map.span_to_snippet(f.ty.span).unwrap())
.collect();
let field_name_to_index = fs
.iter()
.enumerate()
Expand All @@ -421,6 +425,7 @@ pub fn analyze(tcx: TyCtxt<'_>, conf: &Config) {
variant_tags,
empty_tags,
field_names,
field_tys,
field_name_to_index,
struct_local_def_id,
index_in_struct,
Expand Down Expand Up @@ -784,6 +789,7 @@ impl {} {{
suggestions: &mut suggestions,

locals: HashMap::new(),
match_targets: HashMap::new(),
};
visitor.visit_body(hir_body);
}
Expand Down Expand Up @@ -1233,6 +1239,7 @@ struct TaggedUnion {
variant_tags: BTreeMap<FieldIdx, Vec<Tag>>,
empty_tags: Vec<Tag>,
field_names: IndexVec<FieldIdx, String>,
field_tys: IndexVec<FieldIdx, String>,
field_name_to_index: HashMap<String, FieldIdx>,
struct_local_def_id: LocalDefId,
index_in_struct: FieldIdx,
Expand All @@ -1251,6 +1258,7 @@ struct SuggestingVisitor<'a, 'tcx> {
suggestions: &'a mut Suggestions<'tcx>,

locals: HashMap<HirId, &'tcx Expr<'tcx>>,
match_targets: HashMap<Span, String>,
}

impl<'tcx> SuggestingVisitor<'_, 'tcx> {
Expand All @@ -1267,6 +1275,9 @@ impl<'tcx> SuggestingVisitor<'_, 'tcx> {
ExprKind::Field(expr_struct, _) => {
let span = expr.span.with_lo(expr_struct.span.hi());
self.suggestions.add(span, format!(".{}", union_field_name));

let s = source_map.span_to_snippet(expr_struct.span).unwrap();
self.match_targets.insert(expr.span, normalize_expr_str(&s));
}
ExprKind::Path(QPath::Resolved(_, path)) => {
let Res::Local(hir_id) = path.res else { unreachable!() };
Expand All @@ -1275,6 +1286,8 @@ impl<'tcx> SuggestingVisitor<'_, 'tcx> {
let struct_str = source_map.span_to_snippet(expr_struct.span).unwrap();
self.suggestions
.add(expr.span, format!("{}.{}", struct_str, union_field_name));
self.match_targets
.insert(expr.span, normalize_expr_str(&struct_str));
}
_ => unreachable!("{:?}", expr),
}
Expand All @@ -1291,12 +1304,6 @@ impl<'tcx> SuggestingVisitor<'_, 'tcx> {
let pat = if tu.empty_tags.contains(&tag) {
format!("{}::Empty{}", tu.name, tag)
} else {
assert!(matches!(arm.body.kind, ExprKind::Block(_, _)));
let pos = arm.body.span.lo() + BytePos(1);
let span = arm.body.span.with_lo(pos).with_hi(pos);
self.suggestions
.add(span, "let mut __v = __v as *mut _;".to_string());

let f = tu
.variant_tags
.iter()
Expand All @@ -1310,6 +1317,14 @@ impl<'tcx> SuggestingVisitor<'_, 'tcx> {
},
)
.unwrap();

assert!(matches!(arm.body.kind, ExprKind::Block(_, _)));
let pos = arm.body.span.lo() + BytePos(1);
let span = arm.body.span.with_lo(pos).with_hi(pos);
let f_ty = &tu.field_tys[f];
let code = format!("let mut __v = __v as *mut {};", f_ty);
self.suggestions.add(span, code);

let f_name = &tu.field_names[f];
format!("{}::{}{}(ref mut __v)", tu.name, f_name, tag)
};
Expand Down Expand Up @@ -1423,57 +1438,75 @@ impl<'tcx> SuggestingVisitor<'_, 'tcx> {
}
}
} else if let Some(tu) = self.unions.get(&did) {
let (ctx, _) = get_expr_context(expr, self.tcx);
match ctx {
ExprContext::Value => {
let call = format!("get_{}()", field.name);
self.suggestions.add(field.span, call);
}
ExprContext::Store(_) | ExprContext::Address => {
let span = expr.span.shrink_to_lo();
self.suggestions.add(span, "(*".to_string());

let ItemKind::Union(VariantData::Struct(fs, _), _) =
self.tcx.hir().expect_item(did).kind
else {
unreachable!()
};
let (i, _) = fs
.iter()
.enumerate()
.find(|(_, f)| f.ident.name == field.name)
.unwrap();
let tags = &tu.variant_tags[&FieldIdx::from(i)];

let call = if tags.len() == 1 {
format!("deref_{}_mut())", field.name)
} else {
let ts = &self.structs[&tu.struct_local_def_id];
let field_name = &ts.field_names[ts.tag_index];
let ExprKind::Field(e2, _) = e.kind else { unreachable!() };
let tag = format!(
"{}.{}",
source_map.span_to_snippet(e2.span).unwrap(),
field_name,
);
format!("deref_{}_mut({}()))", field.name, tag)
};
self.suggestions.add(field.span, call);

let root = get_root(expr);
if let ExprKind::Unary(UnOp::Deref, e) = root.kind {
let ty = self.typeck.expr_ty(e);
if let TyKind::RawPtr(TypeAndMut {
mutbl: Mutability::Not,
ty,
}) = ty.kind()
{
let span = e.span.shrink_to_lo();
self.suggestions.add(span, "(".to_string());
let matched = if let Some((match_span, _)) = self
.access_in_matches
.iter()
.find(|(_, ams)| ams.iter().any(|am| am.arm_span.contains(expr.span)))
{
let s1 = &self.match_targets[match_span];
let ExprKind::Field(expr_struct, _) = e.kind else { unreachable!() };
let struct_str = source_map.span_to_snippet(expr_struct.span).unwrap();
let s2 = normalize_expr_str(&struct_str);
s1 == &s2
} else {
false
};

if matched {
self.suggestions.add(expr.span, "(*__v)".to_string());
} else {
let (ctx, _) = get_expr_context(expr, self.tcx);
match ctx {
ExprContext::Value => {
let call = format!("get_{}()", field.name);
self.suggestions.add(field.span, call);
}
ExprContext::Store(_) | ExprContext::Address => {
let span = expr.span.shrink_to_lo();
self.suggestions.add(span, "(*".to_string());

let ItemKind::Union(VariantData::Struct(fs, _), _) =
self.tcx.hir().expect_item(did).kind
else {
unreachable!()
};
let (i, _) = fs
.iter()
.enumerate()
.find(|(_, f)| f.ident.name == field.name)
.unwrap();
let tags = &tu.variant_tags[&FieldIdx::from(i)];

let call = if tags.len() == 1 {
format!("deref_{}_mut())", field.name)
} else {
let ts = &self.structs[&tu.struct_local_def_id];
let field_name = &ts.field_names[ts.tag_index];
let ExprKind::Field(e2, _) = e.kind else { unreachable!() };
let tag = format!(
"{}.{}",
source_map.span_to_snippet(e2.span).unwrap(),
field_name,
);
format!("deref_{}_mut({}()))", field.name, tag)
};
self.suggestions.add(field.span, call);

let root = get_root(expr);
if let ExprKind::Unary(UnOp::Deref, e) = root.kind {
let ty = self.typeck.expr_ty(e);
if let TyKind::RawPtr(TypeAndMut {
mutbl: Mutability::Not,
ty,
}) = ty.kind()
{
let span = e.span.shrink_to_lo();
self.suggestions.add(span, "(".to_string());

let span = e.span.shrink_to_hi();
let cast = format!(" as *mut crate::{:?})", ty);
self.suggestions.add(span, cast);
let span = e.span.shrink_to_hi();
let cast = format!(" as *mut crate::{:?})", ty);
self.suggestions.add(span, cast);
}
}
}
}
Expand Down Expand Up @@ -1995,3 +2028,9 @@ fn unwrap_cast<'a, 'tcx>(e: &'a Expr<'tcx>) -> &'a Expr<'tcx> {
let ExprKind::Cast(e, _) = e.kind else { return e };
unwrap_cast(e)
}

fn normalize_expr_str(s: &str) -> String {
s.chars()
.filter(|&c| !c.is_whitespace() && c != '(' && c != ')')
.collect()
}

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