Adding upstream version 124.0.1.upstream/124.0.1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 991 insertions, 0 deletions

diff --git a/third_party/rust/wast/src/component/types.rs b/third_party/rust/wast/src/component/types.rs
new file mode 100644
index 0000000000..72eced02a8
--- /dev/null
+++ b/third_party/rust/wast/src/component/types.rs
@@ -0,0 +1,991 @@
+use crate::component::*;
+use crate::core;
+use crate::kw;
+use crate::parser::Lookahead1;
+use crate::parser::Peek;
+use crate::parser::{Parse, Parser, Result};
+use crate::token::Index;
+use crate::token::LParen;
+use crate::token::{Id, NameAnnotation, Span};
+
+/// A core type declaration.
+#[derive(Debug)]
+pub struct CoreType<'a> {
+    /// Where this type was defined.
+    pub span: Span,
+    /// An optional identifier to refer to this `core type` by as part of name
+    /// resolution.
+    pub id: Option<Id<'a>>,
+    /// An optional name for this type stored in the custom `name` section.
+    pub name: Option<NameAnnotation<'a>>,
+    /// The core type's definition.
+    pub def: CoreTypeDef<'a>,
+}
+
+impl<'a> Parse<'a> for CoreType<'a> {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        let span = parser.parse::<kw::core>()?.0;
+        parser.parse::<kw::r#type>()?;
+        let id = parser.parse()?;
+        let name = parser.parse()?;
+        let def = parser.parens(|p| p.parse())?;
+
+        Ok(Self {
+            span,
+            id,
+            name,
+            def,
+        })
+    }
+}
+
+/// Represents a core type definition.
+///
+/// In the future this may be removed when module types are a part of
+/// a core module.
+#[derive(Debug)]
+pub enum CoreTypeDef<'a> {
+    /// The type definition is one of the core types.
+    Def(core::TypeDef<'a>),
+    /// The type definition is a module type.
+    Module(ModuleType<'a>),
+}
+
+impl<'a> Parse<'a> for CoreTypeDef<'a> {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        if parser.peek::<kw::module>()? {
+            parser.parse::<kw::module>()?;
+            Ok(Self::Module(parser.parse()?))
+        } else {
+            Ok(Self::Def(parser.parse()?))
+        }
+    }
+}
+
+/// A type definition for a core module.
+#[derive(Debug)]
+pub struct ModuleType<'a> {
+    /// The declarations of the module type.
+    pub decls: Vec<ModuleTypeDecl<'a>>,
+}
+
+impl<'a> Parse<'a> for ModuleType<'a> {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        parser.depth_check()?;
+        Ok(Self {
+            decls: parser.parse()?,
+        })
+    }
+}
+
+/// The declarations of a [`ModuleType`].
+#[derive(Debug)]
+pub enum ModuleTypeDecl<'a> {
+    /// A core type.
+    Type(core::Type<'a>),
+    /// An alias local to the component type.
+    Alias(Alias<'a>),
+    /// An import.
+    Import(core::Import<'a>),
+    /// An export.
+    Export(&'a str, core::ItemSig<'a>),
+}
+
+impl<'a> Parse<'a> for ModuleTypeDecl<'a> {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        let mut l = parser.lookahead1();
+        if l.peek::<kw::r#type>()? {
+            Ok(Self::Type(parser.parse()?))
+        } else if l.peek::<kw::alias>()? {
+            Ok(Self::Alias(Alias::parse_outer_core_type_alias(parser)?))
+        } else if l.peek::<kw::import>()? {
+            Ok(Self::Import(parser.parse()?))
+        } else if l.peek::<kw::export>()? {
+            parser.parse::<kw::export>()?;
+            let name = parser.parse()?;
+            let et = parser.parens(|parser| parser.parse())?;
+            Ok(Self::Export(name, et))
+        } else {
+            Err(l.error())
+        }
+    }
+}
+
+impl<'a> Parse<'a> for Vec<ModuleTypeDecl<'a>> {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        let mut decls = Vec::new();
+        while !parser.is_empty() {
+            decls.push(parser.parens(|parser| parser.parse())?);
+        }
+        Ok(decls)
+    }
+}
+
+/// A type declaration in a component.
+#[derive(Debug)]
+pub struct Type<'a> {
+    /// Where this type was defined.
+    pub span: Span,
+    /// An optional identifier to refer to this `type` by as part of name
+    /// resolution.
+    pub id: Option<Id<'a>>,
+    /// An optional name for this type stored in the custom `name` section.
+    pub name: Option<NameAnnotation<'a>>,
+    /// If present, inline export annotations which indicate names this
+    /// definition should be exported under.
+    pub exports: InlineExport<'a>,
+    /// The type definition.
+    pub def: TypeDef<'a>,
+}
+
+impl<'a> Type<'a> {
+    /// Parses a `Type` while allowing inline `(export "...")` names to be
+    /// defined.
+    pub fn parse_maybe_with_inline_exports(parser: Parser<'a>) -> Result<Self> {
+        Type::parse(parser, true)
+    }
+
+    fn parse_no_inline_exports(parser: Parser<'a>) -> Result<Self> {
+        Type::parse(parser, false)
+    }
+
+    fn parse(parser: Parser<'a>, allow_inline_exports: bool) -> Result<Self> {
+        let span = parser.parse::<kw::r#type>()?.0;
+        let id = parser.parse()?;
+        let name = parser.parse()?;
+        let exports = if allow_inline_exports {
+            parser.parse()?
+        } else {
+            Default::default()
+        };
+        let def = parser.parse()?;
+
+        Ok(Self {
+            span,
+            id,
+            name,
+            exports,
+            def,
+        })
+    }
+}
+
+/// A definition of a component type.
+#[derive(Debug)]
+pub enum TypeDef<'a> {
+    /// A defined value type.
+    Defined(ComponentDefinedType<'a>),
+    /// A component function type.
+    Func(ComponentFunctionType<'a>),
+    /// A component type.
+    Component(ComponentType<'a>),
+    /// An instance type.
+    Instance(InstanceType<'a>),
+    /// A resource type.
+    Resource(ResourceType<'a>),
+}
+
+impl<'a> Parse<'a> for TypeDef<'a> {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        if parser.peek::<LParen>()? {
+            parser.parens(|parser| {
+                let mut l = parser.lookahead1();
+                if l.peek::<kw::func>()? {
+                    parser.parse::<kw::func>()?;
+                    Ok(Self::Func(parser.parse()?))
+                } else if l.peek::<kw::component>()? {
+                    parser.parse::<kw::component>()?;
+                    Ok(Self::Component(parser.parse()?))
+                } else if l.peek::<kw::instance>()? {
+                    parser.parse::<kw::instance>()?;
+                    Ok(Self::Instance(parser.parse()?))
+                } else if l.peek::<kw::resource>()? {
+                    parser.parse::<kw::resource>()?;
+                    Ok(Self::Resource(parser.parse()?))
+                } else {
+                    Ok(Self::Defined(ComponentDefinedType::parse_non_primitive(
+                        parser, l,
+                    )?))
+                }
+            })
+        } else {
+            // Only primitive types have no parens
+            Ok(Self::Defined(ComponentDefinedType::Primitive(
+                parser.parse()?,
+            )))
+        }
+    }
+}
+
+/// A primitive value type.
+#[allow(missing_docs)]
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum PrimitiveValType {
+    Bool,
+    S8,
+    U8,
+    S16,
+    U16,
+    S32,
+    U32,
+    S64,
+    U64,
+    Float32,
+    Float64,
+    Char,
+    String,
+}
+
+impl<'a> Parse<'a> for PrimitiveValType {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        let mut l = parser.lookahead1();
+        if l.peek::<kw::bool_>()? {
+            parser.parse::<kw::bool_>()?;
+            Ok(Self::Bool)
+        } else if l.peek::<kw::s8>()? {
+            parser.parse::<kw::s8>()?;
+            Ok(Self::S8)
+        } else if l.peek::<kw::u8>()? {
+            parser.parse::<kw::u8>()?;
+            Ok(Self::U8)
+        } else if l.peek::<kw::s16>()? {
+            parser.parse::<kw::s16>()?;
+            Ok(Self::S16)
+        } else if l.peek::<kw::u16>()? {
+            parser.parse::<kw::u16>()?;
+            Ok(Self::U16)
+        } else if l.peek::<kw::s32>()? {
+            parser.parse::<kw::s32>()?;
+            Ok(Self::S32)
+        } else if l.peek::<kw::u32>()? {
+            parser.parse::<kw::u32>()?;
+            Ok(Self::U32)
+        } else if l.peek::<kw::s64>()? {
+            parser.parse::<kw::s64>()?;
+            Ok(Self::S64)
+        } else if l.peek::<kw::u64>()? {
+            parser.parse::<kw::u64>()?;
+            Ok(Self::U64)
+        } else if l.peek::<kw::float32>()? {
+            parser.parse::<kw::float32>()?;
+            Ok(Self::Float32)
+        } else if l.peek::<kw::float64>()? {
+            parser.parse::<kw::float64>()?;
+            Ok(Self::Float64)
+        } else if l.peek::<kw::char>()? {
+            parser.parse::<kw::char>()?;
+            Ok(Self::Char)
+        } else if l.peek::<kw::string>()? {
+            parser.parse::<kw::string>()?;
+            Ok(Self::String)
+        } else {
+            Err(l.error())
+        }
+    }
+}
+
+impl Peek for PrimitiveValType {
+    fn peek(cursor: crate::parser::Cursor<'_>) -> Result<bool> {
+        Ok(matches!(
+            cursor.keyword()?,
+            Some(("bool", _))
+                | Some(("s8", _))
+                | Some(("u8", _))
+                | Some(("s16", _))
+                | Some(("u16", _))
+                | Some(("s32", _))
+                | Some(("u32", _))
+                | Some(("s64", _))
+                | Some(("u64", _))
+                | Some(("float32", _))
+                | Some(("float64", _))
+                | Some(("char", _))
+                | Some(("string", _))
+        ))
+    }
+
+    fn display() -> &'static str {
+        "primitive value type"
+    }
+}
+
+/// A component value type.
+#[allow(missing_docs)]
+#[derive(Debug)]
+pub enum ComponentValType<'a> {
+    /// The value type is an inline defined type.
+    Inline(ComponentDefinedType<'a>),
+    /// The value type is an index reference to a defined type.
+    Ref(Index<'a>),
+}
+
+impl<'a> Parse<'a> for ComponentValType<'a> {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        if parser.peek::<Index<'_>>()? {
+            Ok(Self::Ref(parser.parse()?))
+        } else {
+            Ok(Self::Inline(InlineComponentValType::parse(parser)?.0))
+        }
+    }
+}
+
+impl Peek for ComponentValType<'_> {
+    fn peek(cursor: crate::parser::Cursor<'_>) -> Result<bool> {
+        Ok(Index::peek(cursor)? || ComponentDefinedType::peek(cursor)?)
+    }
+
+    fn display() -> &'static str {
+        "component value type"
+    }
+}
+
+/// An inline-only component value type.
+///
+/// This variation does not parse type indexes.
+#[allow(missing_docs)]
+#[derive(Debug)]
+pub struct InlineComponentValType<'a>(ComponentDefinedType<'a>);
+
+impl<'a> Parse<'a> for InlineComponentValType<'a> {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        if parser.peek::<LParen>()? {
+            parser.parens(|parser| {
+                Ok(Self(ComponentDefinedType::parse_non_primitive(
+                    parser,
+                    parser.lookahead1(),
+                )?))
+            })
+        } else {
+            Ok(Self(ComponentDefinedType::Primitive(parser.parse()?)))
+        }
+    }
+}
+
+// A component defined type.
+#[allow(missing_docs)]
+#[derive(Debug)]
+pub enum ComponentDefinedType<'a> {
+    Primitive(PrimitiveValType),
+    Record(Record<'a>),
+    Variant(Variant<'a>),
+    List(List<'a>),
+    Tuple(Tuple<'a>),
+    Flags(Flags<'a>),
+    Enum(Enum<'a>),
+    Option(OptionType<'a>),
+    Result(ResultType<'a>),
+    Own(Index<'a>),
+    Borrow(Index<'a>),
+}
+
+impl<'a> ComponentDefinedType<'a> {
+    fn parse_non_primitive(parser: Parser<'a>, mut l: Lookahead1<'a>) -> Result<Self> {
+        parser.depth_check()?;
+        if l.peek::<kw::record>()? {
+            Ok(Self::Record(parser.parse()?))
+        } else if l.peek::<kw::variant>()? {
+            Ok(Self::Variant(parser.parse()?))
+        } else if l.peek::<kw::list>()? {
+            Ok(Self::List(parser.parse()?))
+        } else if l.peek::<kw::tuple>()? {
+            Ok(Self::Tuple(parser.parse()?))
+        } else if l.peek::<kw::flags>()? {
+            Ok(Self::Flags(parser.parse()?))
+        } else if l.peek::<kw::enum_>()? {
+            Ok(Self::Enum(parser.parse()?))
+        } else if l.peek::<kw::option>()? {
+            Ok(Self::Option(parser.parse()?))
+        } else if l.peek::<kw::result>()? {
+            Ok(Self::Result(parser.parse()?))
+        } else if l.peek::<kw::own>()? {
+            parser.parse::<kw::own>()?;
+            Ok(Self::Own(parser.parse()?))
+        } else if l.peek::<kw::borrow>()? {
+            parser.parse::<kw::borrow>()?;
+            Ok(Self::Borrow(parser.parse()?))
+        } else {
+            Err(l.error())
+        }
+    }
+}
+
+impl Default for ComponentDefinedType<'_> {
+    fn default() -> Self {
+        Self::Primitive(PrimitiveValType::Bool)
+    }
+}
+
+impl Peek for ComponentDefinedType<'_> {
+    fn peek(cursor: crate::parser::Cursor<'_>) -> Result<bool> {
+        if PrimitiveValType::peek(cursor)? {
+            return Ok(true);
+        }
+
+        Ok(match cursor.lparen()? {
+            Some(cursor) => matches!(
+                cursor.keyword()?,
+                Some(("record", _))
+                    | Some(("variant", _))
+                    | Some(("list", _))
+                    | Some(("tuple", _))
+                    | Some(("flags", _))
+                    | Some(("enum", _))
+                    | Some(("option", _))
+                    | Some(("result", _))
+                    | Some(("own", _))
+                    | Some(("borrow", _))
+            ),
+            None => false,
+        })
+    }
+
+    fn display() -> &'static str {
+        "component defined type"
+    }
+}
+
+/// A record defined type.
+#[derive(Debug)]
+pub struct Record<'a> {
+    /// The fields of the record.
+    pub fields: Vec<RecordField<'a>>,
+}
+
+impl<'a> Parse<'a> for Record<'a> {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        parser.parse::<kw::record>()?;
+        let mut fields = Vec::new();
+        while !parser.is_empty() {
+            fields.push(parser.parens(|p| p.parse())?);
+        }
+        Ok(Self { fields })
+    }
+}
+
+/// A record type field.
+#[derive(Debug)]
+pub struct RecordField<'a> {
+    /// The name of the field.
+    pub name: &'a str,
+    /// The type of the field.
+    pub ty: ComponentValType<'a>,
+}
+
+impl<'a> Parse<'a> for RecordField<'a> {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        parser.parse::<kw::field>()?;
+        Ok(Self {
+            name: parser.parse()?,
+            ty: parser.parse()?,
+        })
+    }
+}
+
+/// A variant defined type.
+#[derive(Debug)]
+pub struct Variant<'a> {
+    /// The cases of the variant type.
+    pub cases: Vec<VariantCase<'a>>,
+}
+
+impl<'a> Parse<'a> for Variant<'a> {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        parser.parse::<kw::variant>()?;
+        let mut cases = Vec::new();
+        while !parser.is_empty() {
+            cases.push(parser.parens(|p| p.parse())?);
+        }
+        Ok(Self { cases })
+    }
+}
+
+/// A case of a variant type.
+#[derive(Debug)]
+pub struct VariantCase<'a> {
+    /// Where this `case` was defined
+    pub span: Span,
+    /// An optional identifier to refer to this case by as part of name
+    /// resolution.
+    pub id: Option<Id<'a>>,
+    /// The name of the case.
+    pub name: &'a str,
+    /// The optional type of the case.
+    pub ty: Option<ComponentValType<'a>>,
+    /// The optional refinement.
+    pub refines: Option<Refinement<'a>>,
+}
+
+impl<'a> Parse<'a> for VariantCase<'a> {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        let span = parser.parse::<kw::case>()?.0;
+        let id = parser.parse()?;
+        let name = parser.parse()?;
+        let ty = parser.parse()?;
+        let refines = if !parser.is_empty() {
+            Some(parser.parse()?)
+        } else {
+            None
+        };
+        Ok(Self {
+            span,
+            id,
+            name,
+            ty,
+            refines,
+        })
+    }
+}
+
+/// A refinement for a variant case.
+#[derive(Debug)]
+pub enum Refinement<'a> {
+    /// The refinement is referenced by index.
+    Index(Span, Index<'a>),
+    /// The refinement has been resolved to an index into
+    /// the cases of the variant.
+    Resolved(u32),
+}
+
+impl<'a> Parse<'a> for Refinement<'a> {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        parser.parens(|parser| {
+            let span = parser.parse::<kw::refines>()?.0;
+            let id = parser.parse()?;
+            Ok(Self::Index(span, id))
+        })
+    }
+}
+
+/// A list type.
+#[derive(Debug)]
+pub struct List<'a> {
+    /// The element type of the array.
+    pub element: Box<ComponentValType<'a>>,
+}
+
+impl<'a> Parse<'a> for List<'a> {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        parser.parse::<kw::list>()?;
+        Ok(Self {
+            element: Box::new(parser.parse()?),
+        })
+    }
+}
+
+/// A tuple type.
+#[derive(Debug)]
+pub struct Tuple<'a> {
+    /// The types of the fields of the tuple.
+    pub fields: Vec<ComponentValType<'a>>,
+}
+
+impl<'a> Parse<'a> for Tuple<'a> {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        parser.parse::<kw::tuple>()?;
+        let mut fields = Vec::new();
+        while !parser.is_empty() {
+            fields.push(parser.parse()?);
+        }
+        Ok(Self { fields })
+    }
+}
+
+/// A flags type.
+#[derive(Debug)]
+pub struct Flags<'a> {
+    /// The names of the individual flags.
+    pub names: Vec<&'a str>,
+}
+
+impl<'a> Parse<'a> for Flags<'a> {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        parser.parse::<kw::flags>()?;
+        let mut names = Vec::new();
+        while !parser.is_empty() {
+            names.push(parser.parse()?);
+        }
+        Ok(Self { names })
+    }
+}
+
+/// An enum type.
+#[derive(Debug)]
+pub struct Enum<'a> {
+    /// The tag names of the enum.
+    pub names: Vec<&'a str>,
+}
+
+impl<'a> Parse<'a> for Enum<'a> {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        parser.parse::<kw::enum_>()?;
+        let mut names = Vec::new();
+        while !parser.is_empty() {
+            names.push(parser.parse()?);
+        }
+        Ok(Self { names })
+    }
+}
+
+/// An optional type.
+#[derive(Debug)]
+pub struct OptionType<'a> {
+    /// The type of the value, when a value is present.
+    pub element: Box<ComponentValType<'a>>,
+}
+
+impl<'a> Parse<'a> for OptionType<'a> {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        parser.parse::<kw::option>()?;
+        Ok(Self {
+            element: Box::new(parser.parse()?),
+        })
+    }
+}
+
+/// A result type.
+#[derive(Debug)]
+pub struct ResultType<'a> {
+    /// The type on success.
+    pub ok: Option<Box<ComponentValType<'a>>>,
+    /// The type on failure.
+    pub err: Option<Box<ComponentValType<'a>>>,
+}
+
+impl<'a> Parse<'a> for ResultType<'a> {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        parser.parse::<kw::result>()?;
+
+        let ok: Option<ComponentValType> = parser.parse()?;
+        let err: Option<ComponentValType> = if parser.peek::<LParen>()? {
+            Some(parser.parens(|parser| {
+                parser.parse::<kw::error>()?;
+                parser.parse()
+            })?)
+        } else {
+            None
+        };
+
+        Ok(Self {
+            ok: ok.map(Box::new),
+            err: err.map(Box::new),
+        })
+    }
+}
+
+/// A component function type with parameters and result.
+#[derive(Debug)]
+pub struct ComponentFunctionType<'a> {
+    /// The parameters of a function, optionally each having an identifier for
+    /// name resolution and a name for the custom `name` section.
+    pub params: Box<[ComponentFunctionParam<'a>]>,
+    /// The result of a function, optionally each having an identifier for
+    /// name resolution and a name for the custom `name` section.
+    pub results: Box<[ComponentFunctionResult<'a>]>,
+}
+
+impl<'a> Parse<'a> for ComponentFunctionType<'a> {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        let mut params: Vec<ComponentFunctionParam> = Vec::new();
+        while parser.peek2::<kw::param>()? {
+            params.push(parser.parens(|p| p.parse())?);
+        }
+
+        let mut results: Vec<ComponentFunctionResult> = Vec::new();
+        while parser.peek2::<kw::result>()? {
+            results.push(parser.parens(|p| p.parse())?);
+        }
+
+        Ok(Self {
+            params: params.into(),
+            results: results.into(),
+        })
+    }
+}
+
+/// A parameter of a [`ComponentFunctionType`].
+#[derive(Debug)]
+pub struct ComponentFunctionParam<'a> {
+    /// The name of the parameter
+    pub name: &'a str,
+    /// The type of the parameter.
+    pub ty: ComponentValType<'a>,
+}
+
+impl<'a> Parse<'a> for ComponentFunctionParam<'a> {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        parser.parse::<kw::param>()?;
+        Ok(Self {
+            name: parser.parse()?,
+            ty: parser.parse()?,
+        })
+    }
+}
+
+/// A result of a [`ComponentFunctionType`].
+#[derive(Debug)]
+pub struct ComponentFunctionResult<'a> {
+    /// An optionally-specified name of this result
+    pub name: Option<&'a str>,
+    /// The type of the result.
+    pub ty: ComponentValType<'a>,
+}
+
+impl<'a> Parse<'a> for ComponentFunctionResult<'a> {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        parser.parse::<kw::result>()?;
+        Ok(Self {
+            name: parser.parse()?,
+            ty: parser.parse()?,
+        })
+    }
+}
+
+/// The type of an exported item from an component or instance type.
+#[derive(Debug)]
+pub struct ComponentExportType<'a> {
+    /// Where this export was defined.
+    pub span: Span,
+    /// The name of this export.
+    pub name: ComponentExternName<'a>,
+    /// The signature of the item.
+    pub item: ItemSig<'a>,
+}
+
+impl<'a> Parse<'a> for ComponentExportType<'a> {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        let span = parser.parse::<kw::export>()?.0;
+        let id = parser.parse()?;
+        let debug_name = parser.parse()?;
+        let name = parser.parse()?;
+        let item = parser.parens(|p| {
+            let mut item = p.parse::<ItemSigNoName<'_>>()?.0;
+            item.id = id;
+            item.name = debug_name;
+            Ok(item)
+        })?;
+        Ok(Self { span, name, item })
+    }
+}
+
+/// A type definition for a component type.
+#[derive(Debug, Default)]
+pub struct ComponentType<'a> {
+    /// The declarations of the component type.
+    pub decls: Vec<ComponentTypeDecl<'a>>,
+}
+
+impl<'a> Parse<'a> for ComponentType<'a> {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        parser.depth_check()?;
+        Ok(Self {
+            decls: parser.parse()?,
+        })
+    }
+}
+
+/// A declaration of a component type.
+#[derive(Debug)]
+pub enum ComponentTypeDecl<'a> {
+    /// A core type definition local to the component type.
+    CoreType(CoreType<'a>),
+    /// A type definition local to the component type.
+    Type(Type<'a>),
+    /// An alias local to the component type.
+    Alias(Alias<'a>),
+    /// An import of the component type.
+    Import(ComponentImport<'a>),
+    /// An export of the component type.
+    Export(ComponentExportType<'a>),
+}
+
+impl<'a> Parse<'a> for ComponentTypeDecl<'a> {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        let mut l = parser.lookahead1();
+        if l.peek::<kw::core>()? {
+            Ok(Self::CoreType(parser.parse()?))
+        } else if l.peek::<kw::r#type>()? {
+            Ok(Self::Type(Type::parse_no_inline_exports(parser)?))
+        } else if l.peek::<kw::alias>()? {
+            Ok(Self::Alias(parser.parse()?))
+        } else if l.peek::<kw::import>()? {
+            Ok(Self::Import(parser.parse()?))
+        } else if l.peek::<kw::export>()? {
+            Ok(Self::Export(parser.parse()?))
+        } else {
+            Err(l.error())
+        }
+    }
+}
+
+impl<'a> Parse<'a> for Vec<ComponentTypeDecl<'a>> {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        let mut decls = Vec::new();
+        while !parser.is_empty() {
+            decls.push(parser.parens(|parser| parser.parse())?);
+        }
+        Ok(decls)
+    }
+}
+
+/// A type definition for an instance type.
+#[derive(Debug)]
+pub struct InstanceType<'a> {
+    /// The declarations of the instance type.
+    pub decls: Vec<InstanceTypeDecl<'a>>,
+}
+
+impl<'a> Parse<'a> for InstanceType<'a> {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        parser.depth_check()?;
+        Ok(Self {
+            decls: parser.parse()?,
+        })
+    }
+}
+
+/// A declaration of an instance type.
+#[derive(Debug)]
+pub enum InstanceTypeDecl<'a> {
+    /// A core type definition local to the component type.
+    CoreType(CoreType<'a>),
+    /// A type definition local to the instance type.
+    Type(Type<'a>),
+    /// An alias local to the instance type.
+    Alias(Alias<'a>),
+    /// An export of the instance type.
+    Export(ComponentExportType<'a>),
+}
+
+impl<'a> Parse<'a> for InstanceTypeDecl<'a> {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        let mut l = parser.lookahead1();
+        if l.peek::<kw::core>()? {
+            Ok(Self::CoreType(parser.parse()?))
+        } else if l.peek::<kw::r#type>()? {
+            Ok(Self::Type(Type::parse_no_inline_exports(parser)?))
+        } else if l.peek::<kw::alias>()? {
+            Ok(Self::Alias(parser.parse()?))
+        } else if l.peek::<kw::export>()? {
+            Ok(Self::Export(parser.parse()?))
+        } else {
+            Err(l.error())
+        }
+    }
+}
+
+impl<'a> Parse<'a> for Vec<InstanceTypeDecl<'a>> {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        let mut decls = Vec::new();
+        while !parser.is_empty() {
+            decls.push(parser.parens(|parser| parser.parse())?);
+        }
+        Ok(decls)
+    }
+}
+
+/// A type definition for an instance type.
+#[derive(Debug)]
+pub struct ResourceType<'a> {
+    /// Representation, in core WebAssembly, of this resource.
+    pub rep: core::ValType<'a>,
+    /// The declarations of the instance type.
+    pub dtor: Option<CoreItemRef<'a, kw::func>>,
+}
+
+impl<'a> Parse<'a> for ResourceType<'a> {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        let rep = parser.parens(|p| {
+            p.parse::<kw::rep>()?;
+            p.parse()
+        })?;
+        let dtor = if parser.is_empty() {
+            None
+        } else {
+            Some(parser.parens(|p| {
+                p.parse::<kw::dtor>()?;
+                p.parens(|p| p.parse())
+            })?)
+        };
+        Ok(Self { rep, dtor })
+    }
+}
+
+/// A value type declaration used for values in import signatures.
+#[derive(Debug)]
+pub struct ComponentValTypeUse<'a>(pub ComponentValType<'a>);
+
+impl<'a> Parse<'a> for ComponentValTypeUse<'a> {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        match ComponentTypeUse::<'a, InlineComponentValType<'a>>::parse(parser)? {
+            ComponentTypeUse::Ref(i) => Ok(Self(ComponentValType::Ref(i.idx))),
+            ComponentTypeUse::Inline(t) => Ok(Self(ComponentValType::Inline(t.0))),
+        }
+    }
+}
+
+/// A reference to a core type defined in this component.
+///
+/// This is the same as `TypeUse`, but accepts `$T` as shorthand for
+/// `(type $T)`.
+#[derive(Debug, Clone)]
+pub enum CoreTypeUse<'a, T> {
+    /// The type that we're referencing.
+    Ref(CoreItemRef<'a, kw::r#type>),
+    /// The inline type.
+    Inline(T),
+}
+
+impl<'a, T: Parse<'a>> Parse<'a> for CoreTypeUse<'a, T> {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        // Here the core context is assumed, so no core prefix is expected
+        if parser.peek::<LParen>()? && parser.peek2::<CoreItemRef<'a, kw::r#type>>()? {
+            Ok(Self::Ref(parser.parens(|parser| parser.parse())?))
+        } else {
+            Ok(Self::Inline(parser.parse()?))
+        }
+    }
+}
+
+impl<T> Default for CoreTypeUse<'_, T> {
+    fn default() -> Self {
+        let span = Span::from_offset(0);
+        Self::Ref(CoreItemRef {
+            idx: Index::Num(0, span),
+            kind: kw::r#type(span),
+            export_name: None,
+        })
+    }
+}
+
+/// A reference to a type defined in this component.
+///
+/// This is the same as `TypeUse`, but accepts `$T` as shorthand for
+/// `(type $T)`.
+#[derive(Debug, Clone)]
+pub enum ComponentTypeUse<'a, T> {
+    /// The type that we're referencing.
+    Ref(ItemRef<'a, kw::r#type>),
+    /// The inline type.
+    Inline(T),
+}
+
+impl<'a, T: Parse<'a>> Parse<'a> for ComponentTypeUse<'a, T> {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        if parser.peek::<LParen>()? && parser.peek2::<ItemRef<'a, kw::r#type>>()? {
+            Ok(Self::Ref(parser.parens(|parser| parser.parse())?))
+        } else {
+            Ok(Self::Inline(parser.parse()?))
+        }
+    }
+}
+
+impl<T> Default for ComponentTypeUse<'_, T> {
+    fn default() -> Self {
+        let span = Span::from_offset(0);
+        Self::Ref(ItemRef {
+            idx: Index::Num(0, span),
+            kind: kw::r#type(span),
+            export_names: Vec::new(),
+        })
+    }
+}