diff --git a/crates/wast/src/ast/expr.rs b/crates/wast/src/ast/expr.rs
index 1febe48..f0b563c 100644
--- a/crates/wast/src/ast/expr.rs
+++ b/crates/wast/src/ast/expr.rs
@@ -1,4 +1,4 @@
-use crate::ast::{self, kw};
+use crate::ast::{self, kw, RefType};
 use crate::parser::{Parse, Parser, Result};
 use std::mem;
 
@@ -411,8 +411,8 @@ instructions! {
         TableSize(TableArg<'a>) : [0xfc, 0x10] : "table.size",
         TableGrow(TableArg<'a>) : [0xfc, 0x0f] : "table.grow",
 
-        RefNull : [0xd0] : "ref.null",
-        RefIsNull : [0xd1] : "ref.is_null",
+        RefNull(RefType<'a>) : [0xd0] : "ref.null",
+        RefIsNull(RefType<'a>) : [0xd1] : "ref.is_null",
         RefHost(u32) : [0xff] : "ref.host", // only used in test harness
         RefFunc(ast::Index<'a>) : [0xd2] : "ref.func",
 
diff --git a/crates/wast/src/ast/mod.rs b/crates/wast/src/ast/mod.rs
index 35eaf29..07cd6df 100644
--- a/crates/wast/src/ast/mod.rs
+++ b/crates/wast/src/ast/mod.rs
@@ -348,6 +348,8 @@ pub mod kw {
     custom_keyword!(exn);
     custom_keyword!(exnref);
     custom_keyword!(export);
+    custom_keyword!(r#extern = "extern");
+    custom_keyword!(externref);
     custom_keyword!(eq);
     custom_keyword!(eqref);
     custom_keyword!(f32);
diff --git a/crates/wast/src/ast/table.rs b/crates/wast/src/ast/table.rs
index a59bb3a..eee4b24 100644
--- a/crates/wast/src/ast/table.rs
+++ b/crates/wast/src/ast/table.rs
@@ -208,12 +208,12 @@ impl<'a> ElemPayload<'a> {
             let func = parser.parens(|p| match p.parse::<Option<kw::item>>()? {
                 Some(_) => {
                     if parser.peek::<ast::LParen>() {
-                        parser.parens(parse_ref_func)
+                        parser.parens(|p| parse_ref_func(p, ty))
                     } else {
-                        parse_ref_func(parser)
+                        parse_ref_func(parser, ty)
                     }
                 }
-                None => parse_ref_func(p),
+                None => parse_ref_func(parser, ty),
             })?;
             exprs.push(func);
         }
@@ -221,10 +221,14 @@ impl<'a> ElemPayload<'a> {
     }
 }
 
-fn parse_ref_func<'a>(parser: Parser<'a>) -> Result<Option<ast::Index<'a>>> {
+fn parse_ref_func<'a>(parser: Parser<'a>, ty: ast::TableElemType) -> Result<Option<ast::Index<'a>>> {
     let mut l = parser.lookahead1();
     if l.peek::<kw::ref_null>() {
         parser.parse::<kw::ref_null>()?;
+        let null_ty: ast::RefType = parser.parse()?;
+        if null_ty != ty.into() {
+            return Err(parser.error("elem segment item doesn't match elem segment type"));
+        }
         Ok(None)
     } else if l.peek::<kw::ref_func>() {
         parser.parse::<kw::ref_func>()?;
diff --git a/crates/wast/src/ast/types.rs b/crates/wast/src/ast/types.rs
index e0afc46..797792e 100644
--- a/crates/wast/src/ast/types.rs
+++ b/crates/wast/src/ast/types.rs
@@ -12,14 +12,7 @@ pub enum ValType<'a> {
     V128,
     I8,
     I16,
-    Funcref,
-    Anyref,
-    Nullref,
-    Exnref,
-    Ref(ast::Index<'a>),
-    Optref(ast::Index<'a>),
-    Eqref,
-    I31ref,
+    Ref(RefType<'a>),
     Rtt(ast::Index<'a>),
 }
 
@@ -49,52 +42,27 @@ impl<'a> Parse<'a> for ValType<'a> {
             Ok(ValType::I16)
         } else if l.peek::<kw::funcref>() {
             parser.parse::<kw::funcref>()?;
-            Ok(ValType::Funcref)
+            Ok(ValType::Ref(RefType::Func))
         } else if l.peek::<kw::anyfunc>() {
             parser.parse::<kw::anyfunc>()?;
-            Ok(ValType::Funcref)
+            Ok(ValType::Ref(RefType::Func))
+        } else if l.peek::<kw::externref>() {
+            parser.parse::<kw::externref>()?;
+            Ok(ValType::Ref(RefType::Extern))
         } else if l.peek::<kw::anyref>() {
+            // Parse `anyref` as an alias of `externref` until all tests are
+            // ported to use the new name
             parser.parse::<kw::anyref>()?;
-            Ok(ValType::Anyref)
-        } else if l.peek::<kw::nullref>() {
-            parser.parse::<kw::nullref>()?;
-            Ok(ValType::Nullref)
+            Ok(ValType::Ref(RefType::Extern))
         } else if l.peek::<ast::LParen>() {
             parser.parens(|p| {
                 let mut l = parser.lookahead1();
                 if l.peek::<kw::r#ref>() {
                     p.parse::<kw::r#ref>()?;
-
-                    let mut l = parser.lookahead1();
-                    if l.peek::<kw::func>() {
-                        parser.parse::<kw::func>()?;
-                        Ok(ValType::Funcref)
-                    } else if l.peek::<kw::any>() {
-                        parser.parse::<kw::any>()?;
-                        Ok(ValType::Anyref)
-                    } else if l.peek::<kw::null>() {
-                        parser.parse::<kw::null>()?;
-                        Ok(ValType::Nullref)
-                    } else if l.peek::<kw::exn>() {
-                        parser.parse::<kw::exn>()?;
-                        Ok(ValType::Exnref)
-                    } else if l.peek::<kw::eq>() {
-                        parser.parse::<kw::eq>()?;
-                        Ok(ValType::Eqref)
-                    } else if l.peek::<kw::i31>() {
-                        parser.parse::<kw::i31>()?;
-                        Ok(ValType::I31ref)
-                    } else if l.peek::<kw::opt>() {
-                        parser.parse::<kw::opt>()?;
-                        Ok(ValType::Optref(parser.parse()?))
-                    } else if l.peek::<ast::Index>() {
-                        Ok(ValType::Ref(parser.parse()?))
-                    } else {
-                        Err(l.error())
-                    }
+                    Ok(ValType::Ref(p.parse()?))
                 } else if l.peek::<kw::optref>() {
                     p.parse::<kw::optref>()?;
-                    Ok(ValType::Optref(parser.parse()?))
+                    Ok(ValType::Ref(RefType::OptType(parser.parse()?)))
                 } else if l.peek::<kw::rtt>() {
                     p.parse::<kw::rtt>()?;
                     Ok(ValType::Rtt(parser.parse()?))
@@ -104,13 +72,80 @@ impl<'a> Parse<'a> for ValType<'a> {
             })
         } else if l.peek::<kw::exnref>() {
             parser.parse::<kw::exnref>()?;
-            Ok(ValType::Exnref)
+            Ok(ValType::Ref(RefType::Exn))
         } else if l.peek::<kw::eqref>() {
             parser.parse::<kw::eqref>()?;
-            Ok(ValType::Eqref)
+            Ok(ValType::Ref(RefType::Eq))
         } else if l.peek::<kw::i31ref>() {
             parser.parse::<kw::i31ref>()?;
-            Ok(ValType::I31ref)
+            Ok(ValType::Ref(RefType::I31))
+        } else {
+            Err(l.error())
+        }
+    }
+}
+
+/// The reference value types for a wasm module.
+#[allow(missing_docs)]
+#[derive(Debug, PartialEq, Eq, Hash, Copy, Clone)]
+pub enum RefType<'a> {
+    /// An untyped function reference: funcref. This is part of the reference
+    /// types proposal.
+    Func,
+    /// A reference to any host value: externref. This was originally known as
+    /// anyref when it was the supertype of all reference value types. This is
+    /// part of the reference types proposal.
+    Extern,
+    /// A reference to an exception: exnref. This is part of the exception
+    /// handling proposal.
+    Exn,
+    /// A reference that has an identity that can be compared: eqref. This is
+    /// part of the GC proposal.
+    Eq,
+    /// An unboxed 31-bit integer: i31ref. This may be going away if there is no common
+    /// supertype of all reference types. Part of the GC proposal.
+    I31,
+    /// A reference to a function, struct, or array: ref T. This is part of the
+    /// GC proposal.
+    Type(ast::Index<'a>),
+    /// A nullable reference to a function, struct, or array: optref T. This is
+    /// part of the GC proposal.
+    OptType(ast::Index<'a>),
+}
+
+impl<'a> From<TableElemType> for RefType<'a> {
+    fn from(elem: TableElemType) -> Self {
+        match elem {
+            TableElemType::Funcref => RefType::Func,
+            TableElemType::Externref => RefType::Extern,
+            TableElemType::Exnref => RefType::Exn,
+        }
+    }
+}
+
+impl<'a> Parse<'a> for RefType<'a> {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        let mut l = parser.lookahead1();
+        if l.peek::<kw::func>() {
+            parser.parse::<kw::func>()?;
+            Ok(RefType::Func)
+        } else if l.peek::<kw::r#extern>() {
+            parser.parse::<kw::r#extern>()?;
+            Ok(RefType::Extern)
+        } else if l.peek::<kw::exn>() {
+            parser.parse::<kw::exn>()?;
+            Ok(RefType::Exn)
+        } else if l.peek::<kw::eq>() {
+            parser.parse::<kw::eq>()?;
+            Ok(RefType::Eq)
+        } else if l.peek::<kw::i31>() {
+            parser.parse::<kw::i31>()?;
+            Ok(RefType::I31)
+        } else if l.peek::<kw::opt>() {
+            parser.parse::<kw::opt>()?;
+            Ok(RefType::OptType(parser.parse()?))
+        } else if l.peek::<ast::Index>() {
+            Ok(RefType::Type(parser.parse()?))
         } else {
             Err(l.error())
         }
@@ -146,16 +181,12 @@ impl<'a> Parse<'a> for GlobalType<'a> {
 }
 
 /// List of different kinds of table types we can have.
-///
-/// Currently there's only one, a `funcref`.
 #[derive(Copy, Clone, Debug)]
 pub enum TableElemType {
     /// An element for a table that is a list of functions.
     Funcref,
-    /// An element for a table that is a list of `anyref` values.
-    Anyref,
-    /// An element for a table that is a list of `nullref` values.
-    Nullref,
+    /// An element for a table that is a list of `externref` values.
+    Externref,
     /// An element for a table that is a list of `exnref` values.
     Exnref,
 }
@@ -172,11 +203,13 @@ impl<'a> Parse<'a> for TableElemType {
             parser.parse::<kw::funcref>()?;
             Ok(TableElemType::Funcref)
         } else if l.peek::<kw::anyref>() {
+            // Parse `anyref` as an alias of `externref` until all tests are
+            // ported to use the new name
             parser.parse::<kw::anyref>()?;
-            Ok(TableElemType::Anyref)
-        } else if l.peek::<kw::nullref>() {
-            parser.parse::<kw::nullref>()?;
-            Ok(TableElemType::Nullref)
+            Ok(TableElemType::Externref)
+        } else if l.peek::<kw::externref>() {
+            parser.parse::<kw::externref>()?;
+            Ok(TableElemType::Externref)
         } else if l.peek::<kw::exnref>() {
             parser.parse::<kw::exnref>()?;
             Ok(TableElemType::Exnref)
@@ -190,7 +223,7 @@ impl Peek for TableElemType {
     fn peek(cursor: Cursor<'_>) -> bool {
         kw::funcref::peek(cursor)
             || kw::anyref::peek(cursor)
-            || kw::nullref::peek(cursor)
+            || kw::externref::peek(cursor)
             || /* legacy */ kw::anyfunc::peek(cursor)
             || kw::exnref::peek(cursor)
     }
diff --git a/crates/wast/src/binary.rs b/crates/wast/src/binary.rs
index e68890f..96add44 100644
--- a/crates/wast/src/binary.rs
+++ b/crates/wast/src/binary.rs
@@ -250,24 +250,33 @@ impl<'a> Encode for ValType<'a> {
             ValType::V128 => e.push(0x7b),
             ValType::I8 => e.push(0x7a),
             ValType::I16 => e.push(0x79),
-            ValType::Funcref => e.push(0x70),
-            ValType::Anyref => e.push(0x6f),
-            ValType::Nullref => e.push(0x6e),
-            ValType::Ref(index) => {
-                e.push(0x6d);
+            ValType::Ref(ty) => {
+                ty.encode(e);
+            }
+            ValType::Rtt(index) => {
+                e.push(0x69);
                 index.encode(e);
             }
-            ValType::Optref(index) => {
-                e.push(0x6c);
+        }
+    }
+}
+
+impl<'a> Encode for RefType<'a> {
+    fn encode(&self, e: &mut Vec<u8>) {
+        match self {
+            RefType::Func => e.push(0x70),
+            RefType::Extern => e.push(0x6f),
+            RefType::Eq => e.push(0x6b),
+            RefType::I31 => e.push(0x6a),
+            RefType::Exn => e.push(0x68),
+            RefType::Type(index) => {
+                e.push(0x6d);
                 index.encode(e);
             }
-            ValType::Eqref => e.push(0x6b),
-            ValType::I31ref => e.push(0x6a),
-            ValType::Rtt(index) => {
-                e.push(0x69);
+            RefType::OptType(index) => {
+                e.push(0x6c);
                 index.encode(e);
             }
-            ValType::Exnref => e.push(0x68),
         }
     }
 }
@@ -329,10 +338,9 @@ impl Encode for TableType {
 impl Encode for TableElemType {
     fn encode(&self, e: &mut Vec<u8>) {
         match self {
-            TableElemType::Funcref => ValType::Funcref.encode(e),
-            TableElemType::Anyref => ValType::Anyref.encode(e),
-            TableElemType::Nullref => ValType::Nullref.encode(e),
-            TableElemType::Exnref => ValType::Exnref.encode(e),
+            TableElemType::Funcref => RefType::Func.encode(e),
+            TableElemType::Externref => RefType::Extern.encode(e),
+            TableElemType::Exnref => RefType::Exn.encode(e),
         }
     }
 }
@@ -517,7 +525,7 @@ impl Encode for ElemPayload<'_> {
     fn encode(&self, e: &mut Vec<u8>) {
         match self {
             ElemPayload::Indices(v) => v.encode(e),
-            ElemPayload::Exprs { exprs, .. } => {
+            ElemPayload::Exprs { exprs, ty } => {
                 exprs.len().encode(e);
                 for idx in exprs {
                     match idx {
@@ -525,7 +533,7 @@ impl Encode for ElemPayload<'_> {
                             Instruction::RefFunc(*idx).encode(e);
                         }
                         None => {
-                            Instruction::RefNull.encode(e);
+                            Instruction::RefNull((*ty).into()).encode(e);
                         }
                     }
                     Instruction::End(None).encode(e);
diff --git a/crates/wast/src/resolve/names.rs b/crates/wast/src/resolve/names.rs
index e0619f7..19acef7 100644
--- a/crates/wast/src/resolve/names.rs
+++ b/crates/wast/src/resolve/names.rs
@@ -209,7 +209,20 @@ impl<'a> Resolver<'a> {
 
     fn resolve_valtype(&self, ty: &mut ValType<'a>) -> Result<(), Error> {
         match ty {
-            ValType::Ref(i) | ValType::Optref(i) | ValType::Rtt(i) => {
+            ValType::Ref(ty) => self.resolve_reftype(ty)?,
+            ValType::Rtt(i) => {
+                self.ns(Ns::Type)
+                    .resolve(i)
+                    .map_err(|id| self.resolve_error(id, "type"))?;
+            }
+            _ => {}
+        }
+        Ok(())
+    }
+
+    fn resolve_reftype(&self, ty: &mut RefType<'a>) -> Result<(), Error> {
+        match ty {
+            RefType::Type(i) | RefType::OptType(i) => {
                 self.ns(Ns::Type)
                     .resolve(i)
                     .map_err(|id| self.resolve_error(id, "type"))?;
@@ -548,6 +561,8 @@ impl<'a, 'b> ExprResolver<'a, 'b> {
                 self.resolver.resolve_valtype(&mut s.to)
             }
 
+            RefNull(ty) | RefIsNull(ty) => self.resolver.resolve_reftype(ty),
+
             _ => Ok(()),
         }
     }
diff --git a/tests/regression/gc-struct.wat b/tests/regression/gc-struct.wat
index 0c3bf43..9aec0cc 100644
--- a/tests/regression/gc-struct.wat
+++ b/tests/regression/gc-struct.wat
@@ -21,6 +21,5 @@
   (func
     struct.narrow i32 f32
     struct.narrow anyref funcref
-    struct.narrow anyref nullref
   )
 )
diff --git a/tests/wabt.rs b/tests/wabt.rs
index 75ea51c..c20f366 100644
--- a/tests/wabt.rs
+++ b/tests/wabt.rs
@@ -505,5 +505,23 @@ fn skip_test(test: &Path, contents: &str) -> bool {
         return true;
     }
 
+    // Waiting for wabt to remove subtyping from reference-types.
+    if test
+        .iter()
+        .any(|x| x == "bulk-memory-operations" || x == "reference-types")
+        || test.ends_with("reference-types.txt")
+        || test.ends_with("all-features.txt")
+        || test.ends_with("all-features.txt")
+        || test.ends_with("bulk-memory-named.txt")
+        || test.ends_with("reference-types-named.txt")
+        || test.ends_with("table-grow.txt")
+        || test.ends_with("result-exnref.txt")
+        || test.ends_with("global-exnref.txt")
+        || test.ends_with("global.txt")
+        || test.ends_with("bulk-memory.txt")
+    {
+        return true;
+    }
+
     false
 }