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Diffstat (limited to 'crates/hir-def/src/data/adt.rs')
| -rw-r--r-- | crates/hir-def/src/data/adt.rs | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/crates/hir-def/src/data/adt.rs b/crates/hir-def/src/data/adt.rs index a70710e565..ba54451e59 100644 --- a/crates/hir-def/src/data/adt.rs +++ b/crates/hir-def/src/data/adt.rs @@ -14,6 +14,7 @@ use triomphe::Arc; use crate::{ builtin_type::{BuiltinInt, BuiltinUint}, db::DefDatabase, + hir::Expr, item_tree::{ AttrOwner, Field, FieldParent, FieldsShape, ItemTree, ModItem, RawVisibilityId, TreeId, }, @@ -317,6 +318,27 @@ impl EnumData { _ => IntegerType::Pointer(true), } } + + // [Adopted from rustc](https://github.com/rust-lang/rust/blob/bd53aa3bf7a24a70d763182303bd75e5fc51a9af/compiler/rustc_middle/src/ty/adt.rs#L446-L448) + pub fn is_payload_free(&self, db: &dyn DefDatabase) -> bool { + self.variants.iter().all(|(v, _)| { + // The condition check order is slightly modified from rustc + // to improve performance by early returning with relatively fast checks + let variant = &db.enum_variant_data(*v).variant_data; + if !variant.fields().is_empty() { + return false; + } + // The outer if condition is whether this variant has const ctor or not + if !matches!(variant.kind(), StructKind::Unit) { + let body = db.body((*v).into()); + // A variant with explicit discriminant + if body.exprs[body.body_expr] != Expr::Missing { + return false; + } + } + true + }) + } } impl EnumVariantData { |