fix: [x; _] bug

crates/erg_compiler/context/eval.rs

@@ -1809,6 +1809,10 @@ impl Context {
                 }
                 Ok(array_t(union, TyParam::value(len)))
             }
+            TyParam::UnsizedArray(elem) => {
+                let elem = self.convert_tp_into_type(*elem)?;
+                Ok(unknown_len_array_t(elem))
+            }
             TyParam::Set(tps) => {
                 let mut union = Type::Never;
                 for tp in tps.iter() {
@@ -1874,6 +1878,10 @@ impl Context {
                 }
                 Ok(ValueObj::Array(new.into()))
             }
+            TyParam::UnsizedArray(elem) => {
+                let elem = self.convert_tp_into_value(*elem)?;
+                Ok(ValueObj::UnsizedArray(Box::new(elem)))
+            }
             TyParam::Tuple(tys) => {
                 let mut new = vec![];
                 for elem in tys {
@@ -1978,6 +1986,13 @@ impl Context {
                 }
                 Ok(TyParam::Array(new_arr))
             }
+            ValueObj::UnsizedArray(elem) => {
+                let tp = match Self::convert_value_into_tp(*elem) {
+                    Ok(tp) => tp,
+                    Err(tp) => tp,
+                };
+                Ok(TyParam::UnsizedArray(Box::new(tp)))
+            }
             ValueObj::Tuple(vs) => {
                 let mut new_ts = vec![];
                 for v in vs.iter().cloned() {

crates/erg_compiler/ty/typaram.rs

@@ -237,6 +237,7 @@ pub enum TyParam {
     Value(ValueObj),
     Type(Box<Type>),
     Array(Vec<TyParam>),
+    UnsizedArray(Box<TyParam>),
     Tuple(Vec<TyParam>),
     Set(Set<TyParam>),
     Dict(Dict<TyParam, TyParam>),
@@ -280,6 +281,7 @@ impl PartialEq for TyParam {
             (Self::Value(l), Self::Value(r)) => l == r,
             (Self::Type(l), Self::Type(r)) => l == r,
             (Self::Array(l), Self::Array(r)) => l == r,
+            (Self::UnsizedArray(l), Self::UnsizedArray(r)) => l == r,
             (Self::Tuple(l), Self::Tuple(r)) => l == r,
             (Self::Dict(l), Self::Dict(r)) => l == r,
             (Self::Record(l), Self::Record(r)) => l == r,
@@ -423,6 +425,11 @@ impl LimitedDisplay for TyParam {
                 }
                 write!(f, "]")
             }
+            Self::UnsizedArray(elem) => {
+                write!(f, "[")?;
+                elem.limited_fmt(f, limit - 1)?;
+                write!(f, "; _]")
+            }
             Self::Set(st) => {
                 write!(f, "{{")?;
                 for (i, t) in st.iter().enumerate() {

tests/should_ok/container_class.er

@@ -0,0 +1,3 @@
+D = Class { Int: [Str; _] }
+_ = D.new {:}
+_ = D.new {1: ["a"]}

tests/test.rs

@@ -65,6 +65,11 @@ fn exec_comprehension() -> Result<(), ()> {
     expect_success("tests/should_ok/comprehension.er", 0)
 }
 
+#[test]
+fn exec_container_class() -> Result<(), ()> {
+    expect_success("tests/should_ok/container_class.er", 0)
+}
+
 #[test]
 fn exec_control() -> Result<(), ()> {
     expect_success("examples/control.er", 2)