Remove union types (#1180)

* Fix formatting for Rust 1.72.0

* Remove union types

---------

Co-authored-by: Alex Crichton <alex@alexcrichton.com>

Author: lann

crates/wasm-compose/src/encoding.rs

@@ -702,7 +702,6 @@ impl<'a> TypeEncoder<'a> {
             wasmparser::types::ComponentDefinedType::Enum(cases) => {
                 Self::enum_type(&mut state.cur.encodable, cases)
             }
-            wasmparser::types::ComponentDefinedType::Union(u) => self.union(state, u),
             wasmparser::types::ComponentDefinedType::Option(ty) => self.option(state, *ty),
             wasmparser::types::ComponentDefinedType::Result { ok, err } => {
                 self.result(state, *ok, *err)
@@ -789,18 +788,6 @@ impl<'a> TypeEncoder<'a> {
         index
     }
 
-    fn union(&self, state: &mut TypeState<'a>, union: &wasmparser::types::UnionType) -> u32 {
-        let types = union
-            .types
-            .iter()
-            .map(|ty| self.component_val_type(state, *ty))
-            .collect::<Vec<_>>();
-
-        let index = state.cur.encodable.type_count();
-        state.cur.encodable.ty().defined_type().union(types);
-        index
-    }
-
     fn option(&self, state: &mut TypeState<'a>, ty: wasmparser::types::ComponentValType) -> u32 {
         let ty = self.component_val_type(state, ty);
 
@@ -1297,11 +1284,6 @@ impl DependencyRegistrar<'_, '_> {
                     }
                 }
             }
-            types::ComponentDefinedType::Union(r) => {
-                for ty in r.types.iter() {
-                    self.val_type(*ty);
-                }
-            }
             types::ComponentDefinedType::Result { ok, err } => {
                 if let Some(ok) = ok {
                     self.val_type(*ok);

crates/wasm-compose/tests/compositions/complex-import/composed.wat

@@ -63,8 +63,8 @@
           (export (;24;) "enum1" (type (eq 23)))
           (type (;25;) (func (param "x" 24)))
           (export (;17;) "r" (func (type 25)))
-          (type (;26;) (union s8 string 14))
-          (export (;27;) "union1" (type (eq 26)))
+          (type (;26;) (option 14))
+          (export (;27;) "option1" (type (eq 26)))
           (type (;28;) (func (param "x" 27)))
           (export (;18;) "s" (func (type 28)))
           (type (;29;) (variant (case "a" s8) (case "b" u8) (case "c" s16) (case "d" u16) (case "e" s32) (case "f" u32) (case "g" s64) (case "h" u64) (case "i" float32) (case "j" float64) (case "k" bool) (case "l" string) (case "m" 14)))
@@ -96,8 +96,8 @@
       (export (;3;) "flags1" (type (eq 2)))
       (type (;4;) (enum "a" "b" "c"))
       (export (;5;) "enum1" (type (eq 4)))
-      (type (;6;) (union s8 string 1))
-      (export (;7;) "union1" (type (eq 6)))
+      (type (;6;) (option 1))
+      (export (;7;) "option1" (type (eq 6)))
       (type (;8;) (variant (case "a" s8) (case "b" u8) (case "c" s16) (case "d" u16) (case "e" s32) (case "f" u32) (case "g" s64) (case "h" u64) (case "i" float32) (case "j" float64) (case "k" bool) (case "l" string) (case "m" 1)))
       (export (;9;) "variant1" (type (eq 8)))
       (type (;10;) (func))

crates/wasm-compose/tests/compositions/complex/a.wat

@@ -25,8 +25,8 @@
   (type $t21' (enum "a" "b" "c"))
   (export $t21 "enum1" (type $t21'))
   (type $t22 (func (param "x" $t21)))
-  (type $t23' (union s8 string $t13))
-  (export $t23 "union1" (type $t23'))
+  (type $t23' (option $t13))
+  (export $t23 "option1" (type $t23'))
   (type $t24 (func (param "x" $t23)))
   (type $t25' (variant (case "a" s8) (case "b" u8) (case "c" s16) (case "d" u16) (case "e" s32) (case "f" u32) (case "g" s64) (case "h" u64) (case "i" float32) (case "j" float64) (case "k" bool) (case "l" string) (case "m" $t13)))
   (export $t25 "variant1" (type $t25'))

crates/wasm-compose/tests/compositions/complex/b.wat

@@ -45,8 +45,8 @@
       (export $t5 "enum1"  (type (eq $t5')))
       (type $f18 (func (param "x" $t5)))
       (export "r" (func (type $f18)))
-      (type $t6' (union s8 string $t1))
-      (export $t6 "union1"  (type (eq $t6')))
+      (type $t6' (option $t1))
+      (export $t6 "option1"  (type (eq $t6')))
       (type $f19 (func (param "x" $t6)))
       (export "s" (func (type $f19)))
       (type $t7' (variant (case "a" s8) (case "b" u8) (case "c" s16) (case "d" u16) (case "e" s32) (case "f" u32) (case "g" s64) (case "h" u64) (case "i" float32) (case "j" float64) (case "k" bool) (case "l" string) (case "m" $t1)))

crates/wasm-compose/tests/compositions/complex/composed.wat

@@ -60,8 +60,8 @@
         (export (;24;) "enum1" (type (eq 23)))
         (type (;25;) (func (param "x" 24)))
         (export (;17;) "r" (func (type 25)))
-        (type (;26;) (union s8 string 14))
-        (export (;27;) "union1" (type (eq 26)))
+        (type (;26;) (option 14))
+        (export (;27;) "option1" (type (eq 26)))
         (type (;28;) (func (param "x" 27)))
         (export (;18;) "s" (func (type 28)))
         (type (;29;) (variant (case "a" s8) (case "b" u8) (case "c" s16) (case "d" u16) (case "e" s32) (case "f" u32) (case "g" s64) (case "h" u64) (case "i" float32) (case "j" float64) (case "k" bool) (case "l" string) (case "m" 14)))
@@ -344,8 +344,8 @@
     (type $t21' (;23;) (enum "a" "b" "c"))
     (export $t21 (;24;) "enum1" (type $t21'))
     (type $t22 (;25;) (func (param "x" $t21)))
-    (type $t23' (;26;) (union s8 string $t13))
-    (export $t23 (;27;) "union1" (type $t23'))
+    (type $t23' (;26;) (option $t13))
+    (export $t23 (;27;) "option1" (type $t23'))
     (type $t24 (;28;) (func (param "x" $t23)))
     (type $t25' (;29;) (variant (case "a" s8) (case "b" u8) (case "c" s16) (case "d" u16) (case "e" s32) (case "f" u32) (case "g" s64) (case "h" u64) (case "i" float32) (case "j" float64) (case "k" bool) (case "l" string) (case "m" $t13)))
     (export $t25 (;30;) "variant1" (type $t25'))

crates/wasm-encoder/src/component/types.rs

@@ -642,21 +642,6 @@ impl ComponentDefinedTypeEncoder<'_> {
         }
     }
 
-    /// Define a union type.
-    pub fn union<I, T>(self, types: I)
-    where
-        I: IntoIterator<Item = T>,
-        I::IntoIter: ExactSizeIterator,
-        T: Into<ComponentValType>,
-    {
-        let types = types.into_iter();
-        self.0.push(0x6C);
-        types.len().encode(self.0);
-        for ty in types {
-            ty.into().encode(self.0);
-        }
-    }
-
     /// Define an option type.
     pub fn option(self, ty: impl Into<ComponentValType>) {
         self.0.push(0x6B);

crates/wasm-smith/src/component.rs

@@ -1453,20 +1453,6 @@ impl ComponentBuilder {
         Ok(EnumType { variants })
     }
 
-    fn arbitrary_union_type(&self, u: &mut Unstructured, type_fuel: &mut u32) -> Result<UnionType> {
-        let mut variants = vec![];
-        arbitrary_loop(u, 1, 100, |u| {
-            *type_fuel = type_fuel.saturating_sub(1);
-            if *type_fuel == 0 {
-                return Ok(false);
-            }
-
-            variants.push(self.arbitrary_component_val_type(u)?);
-            Ok(true)
-        })?;
-        Ok(UnionType { variants })
-    }
-
     fn arbitrary_option_type(&self, u: &mut Unstructured) -> Result<OptionType> {
         Ok(OptionType {
             inner_ty: self.arbitrary_component_val_type(u)?,
@@ -1491,7 +1477,7 @@ impl ComponentBuilder {
         u: &mut Unstructured,
         type_fuel: &mut u32,
     ) -> Result<DefinedType> {
-        match u.int_in_range(0..=9)? {
+        match u.int_in_range(0..=8)? {
             0 => Ok(DefinedType::Primitive(
                 self.arbitrary_primitive_val_type(u)?,
             )),
@@ -1505,9 +1491,8 @@ impl ComponentBuilder {
             4 => Ok(DefinedType::Tuple(self.arbitrary_tuple_type(u, type_fuel)?)),
             5 => Ok(DefinedType::Flags(self.arbitrary_flags_type(u, type_fuel)?)),
             6 => Ok(DefinedType::Enum(self.arbitrary_enum_type(u, type_fuel)?)),
-            7 => Ok(DefinedType::Union(self.arbitrary_union_type(u, type_fuel)?)),
-            8 => Ok(DefinedType::Option(self.arbitrary_option_type(u)?)),
-            9 => Ok(DefinedType::Result(self.arbitrary_result_type(u)?)),
+            7 => Ok(DefinedType::Option(self.arbitrary_option_type(u)?)),
+            8 => Ok(DefinedType::Result(self.arbitrary_result_type(u)?)),
             _ => unreachable!(),
         }
     }
@@ -2120,7 +2105,6 @@ enum DefinedType {
     Tuple(TupleType),
     Flags(FlagsType),
     Enum(EnumType),
-    Union(UnionType),
     Option(OptionType),
     Result(ResultType),
 }
@@ -2155,11 +2139,6 @@ struct EnumType {
     variants: Vec<KebabString>,
 }
 
-#[derive(Clone, Debug, PartialEq, Eq, Hash)]
-struct UnionType {
-    variants: Vec<ComponentValType>,
-}
-
 #[derive(Clone, Debug, PartialEq, Eq, Hash)]
 struct OptionType {
     inner_ty: ComponentValType,

crates/wasm-smith/src/component/encode.rs

@@ -251,9 +251,6 @@ impl DefinedType {
             Self::Enum(ty) => {
                 enc.enum_type(ty.variants.iter().map(|v| v.as_str()));
             }
-            Self::Union(ty) => {
-                enc.union(ty.variants.iter().copied());
-            }
             Self::Option(ty) => {
                 enc.option(ty.inner_ty);
             }

crates/wasmparser/src/limits.rs

@@ -47,7 +47,6 @@ pub const MAX_WASM_VARIANT_CASES: usize = 1000;
 pub const MAX_WASM_TUPLE_TYPES: usize = 1000;
 pub const MAX_WASM_FLAG_NAMES: usize = 1000;
 pub const MAX_WASM_ENUM_CASES: usize = 1000;
-pub const MAX_WASM_UNION_TYPES: usize = 1000;
 pub const MAX_WASM_INSTANTIATION_EXPORTS: usize = 100_000;
 pub const MAX_WASM_CANONICAL_OPTIONS: usize = 10;
 pub const MAX_WASM_INSTANTIATION_ARGS: usize = 100_000;

crates/wasmparser/src/readers/component/types.rs

@@ -470,8 +470,6 @@ pub enum ComponentDefinedType<'a> {
     Flags(Box<[&'a str]>),
     /// The type is an enum with the given tags.
     Enum(Box<[&'a str]>),
-    /// The type is a union of the given value types.
-    Union(Box<[ComponentValType]>),
     /// The type is an option of the given value type.
     Option(ComponentValType),
     /// The type is a result type.
@@ -516,11 +514,7 @@ impl<'a> ComponentDefinedType<'a> {
                     .read_iter(MAX_WASM_ENUM_CASES, "enum cases")?
                     .collect::<Result<_>>()?,
             ),
-            0x6c => ComponentDefinedType::Union(
-                reader
-                    .read_iter(MAX_WASM_UNION_TYPES, "union types")?
-                    .collect::<Result<_>>()?,
-            ),
+            // NOTE: 0x6c (union) removed
             0x6b => ComponentDefinedType::Option(reader.read()?),
             0x6a => ComponentDefinedType::Result {
                 ok: reader.read()?,