feat(parser): TypeScript 5.2 (#811)

- adds support for [Using
Declarations](https://devblogs.microsoft.com/typescript/announcing-typescript-5-2/#using-declarations-and-explicit-resource-management)

Closes #786

crates/oxc_ast/src/ast/js.rs

@@ -993,6 +993,7 @@ pub enum Declaration<'a> {
     VariableDeclaration(Box<'a, VariableDeclaration<'a>>),
     FunctionDeclaration(Box<'a, Function<'a>>),
     ClassDeclaration(Box<'a, Class<'a>>),
+    UsingDeclaration(Box<'a, UsingDeclaration<'a>>),
 
     TSTypeAliasDeclaration(Box<'a, TSTypeAliasDeclaration<'a>>),
     TSInterfaceDeclaration(Box<'a, TSInterfaceDeclaration<'a>>),
@@ -1069,6 +1070,18 @@ pub struct VariableDeclarator<'a> {
     pub definite: bool,
 }
 
+/// Using Declaration
+/// <https://github.com/tc39/proposal-explicit-resource-management>
+#[derive(Debug, Hash)]
+#[cfg_attr(feature = "serde", derive(Serialize), serde(tag = "type", rename_all = "camelCase"))]
+pub struct UsingDeclaration<'a> {
+    #[cfg_attr(feature = "serde", serde(flatten))]
+    pub span: Span,
+    pub is_await: bool,
+    #[cfg_attr(feature = "serde-impl", serde(default))]
+    pub declarations: Vec<'a, VariableDeclarator<'a>>,
+}
+
 /// Empty Statement
 #[derive(Debug, Hash)]
 #[cfg_attr(feature = "serde", derive(Serialize), serde(tag = "type"))]
@@ -1134,6 +1147,7 @@ pub struct ForStatement<'a> {
 pub enum ForStatementInit<'a> {
     VariableDeclaration(Box<'a, VariableDeclaration<'a>>),
     Expression(Expression<'a>),
+    UsingDeclaration(Box<'a, UsingDeclaration<'a>>),
 }
 
 impl<'a> ForStatementInit<'a> {
@@ -1172,6 +1186,7 @@ pub struct ForOfStatement<'a> {
 pub enum ForStatementLeft<'a> {
     VariableDeclaration(Box<'a, VariableDeclaration<'a>>),
     AssignmentTarget(AssignmentTarget<'a>),
+    UsingDeclaration(Box<'a, UsingDeclaration<'a>>),
 }
 
 impl<'a> ForStatementLeft<'a> {

crates/oxc_ast/src/ast_builder.rs

@@ -151,6 +151,19 @@ impl<'a> AstBuilder<'a> {
         Statement::DebuggerStatement(self.alloc(DebuggerStatement { span }))
     }
 
+    pub fn using_statement(
+        &self,
+        span: Span,
+        declarations: Vec<'a, VariableDeclarator<'a>>,
+        is_await: bool,
+    ) -> Statement<'a> {
+        Statement::Declaration(Declaration::UsingDeclaration(self.alloc(UsingDeclaration {
+            span,
+            is_await,
+            declarations,
+        })))
+    }
+
     pub fn do_while_statement(
         &self,
         span: Span,
@@ -742,6 +755,15 @@ impl<'a> AstBuilder<'a> {
         VariableDeclarator { span, kind, id, init, definite }
     }
 
+    pub fn using_declaration(
+        &self,
+        span: Span,
+        declarations: Vec<'a, VariableDeclarator<'a>>,
+        is_await: bool,
+    ) -> UsingDeclaration<'a> {
+        UsingDeclaration { span, is_await, declarations }
+    }
+
     /* ---------- Patterns ---------- */
 
     pub fn binding_pattern(

crates/oxc_ast/src/ast_kind.rs

@@ -37,6 +37,8 @@ pub enum AstKind<'a> {
     VariableDeclaration(&'a VariableDeclaration<'a>),
     VariableDeclarator(&'a VariableDeclarator<'a>),
 
+    UsingDeclaration(&'a UsingDeclaration<'a>),
+
     IdentifierName(&'a IdentifierName),
     IdentifierReference(&'a IdentifierReference),
     BindingIdentifier(&'a BindingIdentifier),
@@ -271,6 +273,8 @@ impl<'a> GetSpan for AstKind<'a> {
             Self::VariableDeclaration(x) => x.span,
             Self::VariableDeclarator(x) => x.span,
 
+            Self::UsingDeclaration(x) => x.span,
+
             Self::IdentifierName(x) => x.span,
             Self::IdentifierReference(x) => x.span,
             Self::BindingIdentifier(x) => x.span,
@@ -421,6 +425,8 @@ impl<'a> AstKind<'a> {
             Self::VariableDeclaration(_) => "VariableDeclaration".into(),
             Self::VariableDeclarator(_) => "VariableDeclarator".into(),
 
+            Self::UsingDeclaration(_) => "UsingDeclaration".into(),
+
             Self::IdentifierName(x) => format!("IdentifierName({})", x.name).into(),
             Self::IdentifierReference(x) => format!("IdentifierReference({})", x.name).into(),
             Self::BindingIdentifier(x) => format!("BindingIdentifier({})", x.name).into(),

crates/oxc_ast/src/span.rs

@@ -169,6 +169,7 @@ impl<'a> GetSpan for Declaration<'a> {
         match self {
             Self::VariableDeclaration(decl) => decl.span,
             Self::FunctionDeclaration(decl) => decl.span,
+            Self::UsingDeclaration(decl) => decl.span,
             Self::ClassDeclaration(decl) => decl.span,
             Self::TSTypeAliasDeclaration(decl) => decl.span,
             Self::TSInterfaceDeclaration(decl) => decl.span,
@@ -235,6 +236,7 @@ impl<'a> GetSpan for ForStatementInit<'a> {
         match self {
             Self::VariableDeclaration(x) => x.span,
             Self::Expression(x) => x.span(),
+            Self::UsingDeclaration(x) => x.span,
         }
     }
 }
@@ -244,6 +246,7 @@ impl<'a> GetSpan for ForStatementLeft<'a> {
         match self {
             Self::VariableDeclaration(x) => x.span,
             Self::AssignmentTarget(x) => x.span(),
+            Self::UsingDeclaration(x) => x.span,
         }
     }
 }

crates/oxc_ast/src/syntax_directed_operations.rs

@@ -95,6 +95,14 @@ impl<'a> BoundNames for VariableDeclaration<'a> {
     }
 }
 
+impl<'a> BoundNames for UsingDeclaration<'a> {
+    fn bound_names<F: FnMut(&BindingIdentifier)>(&self, f: &mut F) {
+        for declarator in &self.declarations {
+            declarator.id.bound_names(f);
+        }
+    }
+}
+
 impl<'a> BoundName for Function<'a> {
     fn bound_name<F: FnMut(&BindingIdentifier)>(&self, f: &mut F) {
         if let Some(ident) = &self.id {

crates/oxc_ast/src/visit.rs

@@ -135,6 +135,9 @@ pub trait Visit<'a>: Sized {
         let kind = AstKind::ForStatementInit(init);
         self.enter_node(kind);
         match init {
+            ForStatementInit::UsingDeclaration(decl) => {
+                self.visit_using_declaration(decl);
+            }
             ForStatementInit::VariableDeclaration(decl) => {
                 self.visit_variable_declaration(decl);
             }
@@ -167,6 +170,9 @@ pub trait Visit<'a>: Sized {
                 self.visit_variable_declaration(decl);
             }
             ForStatementLeft::AssignmentTarget(target) => self.visit_assignment_target(target),
+            ForStatementLeft::UsingDeclaration(decl) => {
+                self.visit_using_declaration(decl);
+            }
         }
     }
 
@@ -450,6 +456,15 @@ pub trait Visit<'a>: Sized {
         self.leave_node(kind);
     }
 
+    fn visit_using_declaration(&mut self, decl: &'a UsingDeclaration<'a>) {
+        let kind = AstKind::UsingDeclaration(decl);
+        self.enter_node(kind);
+        for decl in &decl.declarations {
+            self.visit_variable_declarator(decl);
+        }
+        self.leave_node(kind);
+    }
+
     /* ----------  Expression ---------- */
 
     fn visit_expression(&mut self, expr: &'a Expression<'a>) {
@@ -1264,6 +1279,7 @@ pub trait Visit<'a>: Sized {
             Declaration::VariableDeclaration(decl) => self.visit_variable_declaration(decl),
             Declaration::FunctionDeclaration(func) => self.visit_function(func),
             Declaration::ClassDeclaration(class) => self.visit_class(class),
+            Declaration::UsingDeclaration(decl) => self.visit_using_declaration(decl),
             Declaration::TSModuleDeclaration(module) => {
                 self.visit_ts_module_declaration(module);
             }

crates/oxc_ast/src/visit_mut.rs

@@ -101,6 +101,9 @@ pub trait VisitMut<'a, 'b>: Sized {
                 self.visit_variable_declaration(decl);
             }
             ForStatementInit::Expression(expr) => self.visit_expression(expr),
+            ForStatementInit::UsingDeclaration(decl) => {
+                self.visit_using_declaration(decl);
+            }
         }
     }
 
@@ -122,6 +125,9 @@ pub trait VisitMut<'a, 'b>: Sized {
                 self.visit_variable_declaration(decl);
             }
             ForStatementLeft::AssignmentTarget(target) => self.visit_assignment_target(target),
+            ForStatementLeft::UsingDeclaration(decl) => {
+                self.visit_using_declaration(decl);
+            }
         }
     }
 
@@ -212,6 +218,12 @@ pub trait VisitMut<'a, 'b>: Sized {
         }
     }
 
+    fn visit_using_declaration(&mut self, declaration: &'b mut UsingDeclaration<'a>) {
+        for decl in declaration.declarations.iter_mut() {
+            self.visit_variable_declarator(decl);
+        }
+    }
+
     /* ----------  Function ---------- */
 
     fn visit_function(&mut self, func: &'b mut Function<'a>) {
@@ -960,6 +972,7 @@ pub trait VisitMut<'a, 'b>: Sized {
             Declaration::VariableDeclaration(decl) => self.visit_variable_declaration(decl),
             Declaration::FunctionDeclaration(func) => self.visit_function(func),
             Declaration::ClassDeclaration(class) => self.visit_class(class),
+            Declaration::UsingDeclaration(decl) => self.visit_using_declaration(decl),
             Declaration::TSModuleDeclaration(module) => {
                 self.visit_ts_module_declaration(module);
             }

crates/oxc_formatter/src/gen.rs

@@ -161,6 +161,7 @@ impl<'a> Gen for ForStatement<'a> {
             match init {
                 ForStatementInit::Expression(expr) => expr.gen(p),
                 ForStatementInit::VariableDeclaration(var) => var.gen(p),
+                ForStatementInit::UsingDeclaration(decl) => decl.gen(p),
             }
         }
 
@@ -225,6 +226,7 @@ impl<'a> Gen for ForStatementLeft<'a> {
         match &self {
             ForStatementLeft::VariableDeclaration(var) => var.gen(p),
             ForStatementLeft::AssignmentTarget(target) => target.gen(p),
+            ForStatementLeft::UsingDeclaration(decl) => decl.gen(p),
         }
     }
 }
@@ -447,6 +449,10 @@ impl<'a> Gen for Declaration<'a> {
                 declaration.gen(p);
                 p.print_newline();
             }
+            Self::UsingDeclaration(declaration) => {
+                declaration.gen(p);
+                p.print_newline();
+            }
             Self::TSTypeAliasDeclaration(_)
             | Self::TSInterfaceDeclaration(_)
             | Self::TSEnumDeclaration(_)
@@ -467,6 +473,18 @@ impl<'a> Gen for VariableDeclaration<'a> {
         p.print_list(&self.declarations);
     }
 }
+impl<'a> Gen for UsingDeclaration<'a> {
+    fn gen(&self, p: &mut Formatter) {
+        if self.is_await {
+            p.print_str(b"await");
+            p.print_space();
+        }
+        p.print_str(b"using");
+        p.print_space();
+        p.print_list(&self.declarations);
+        p.print_semicolon();
+    }
+}
 
 impl<'a> Gen for VariableDeclarator<'a> {
     fn gen(&self, p: &mut Formatter) {

crates/oxc_minifier/src/printer/gen.rs

@@ -209,6 +209,7 @@ impl<'a> Gen for ForStatement<'a> {
         if let Some(init) = self.init.as_ref() {
             let ctx = Context::empty();
             match init {
+                ForStatementInit::UsingDeclaration(decl) => decl.gen(p, ctx),
                 ForStatementInit::Expression(expr) => {
                     expr.gen_expr(p, Precedence::lowest(), ctx);
                 }
@@ -267,6 +268,7 @@ impl<'a> Gen for ForOfStatement<'a> {
 impl<'a> Gen for ForStatementLeft<'a> {
     fn gen(&self, p: &mut Printer, ctx: Context) {
         match &self {
+            ForStatementLeft::UsingDeclaration(var) => var.gen(p, ctx),
             ForStatementLeft::VariableDeclaration(var) => var.gen(p, ctx),
             ForStatementLeft::AssignmentTarget(target) => target.gen(p, ctx),
         }
@@ -446,6 +448,9 @@ impl<'a> Gen for Declaration<'a> {
             Self::ClassDeclaration(declaration) => {
                 declaration.gen(p, ctx);
             }
+            Self::UsingDeclaration(declaration) => {
+                declaration.gen(p, ctx);
+            }
             Self::TSEnumDeclaration(_) => {}
         }
     }
@@ -462,6 +467,19 @@ impl<'a> Gen for VariableDeclaration<'a> {
         p.print_list(&self.declarations, ctx);
     }
 }
+impl<'a> Gen for UsingDeclaration<'a> {
+    fn gen(&self, p: &mut Printer, ctx: Context) {
+        if self.is_await {
+            p.print_str(b"await");
+            p.print(b' ');
+        }
+        p.print_str(b"using");
+        p.print(b' ');
+
+        p.print_list(&self.declarations, ctx);
+        p.print_semicolon();
+    }
+}
 
 impl<'a> Gen for VariableDeclarator<'a> {
     fn gen(&self, p: &mut Printer, ctx: Context) {

crates/oxc_parser/src/diagnostics.rs

@@ -281,3 +281,33 @@ pub struct ReturnStatementOnlyInFunctionBody(#[label] pub Span);
 #[error("TS18007: JSX expressions may not use the comma operator.")]
 #[diagnostic(help("Did you mean to write an array?"))]
 pub struct JSXExpressionsMayNotUseTheCommaOperator(#[label] pub Span);
+
+#[derive(Debug, Error, Diagnostic)]
+#[error("Line terminator not permitted before using declaration.")]
+#[diagnostic()]
+pub struct LineTerminatorBeforeUsingDeclaration(#[label] pub Span);
+
+#[derive(Debug, Error, Diagnostic)]
+#[error("Await is not allowed in using declarations.")]
+#[diagnostic()]
+pub struct AwaitInUsingDeclaration(#[label] pub Span);
+
+#[derive(Debug, Error, Diagnostic)]
+#[error("Using declarations may not have binding patterns.")]
+#[diagnostic()]
+pub struct InvalidIdentifierInUsingDeclaration(#[label] pub Span);
+
+#[derive(Debug, Error, Diagnostic)]
+#[error("The left-hand side of a for...in statement cannot be an await using declaration.")]
+#[diagnostic()]
+pub struct AwaitUsingDeclarationNotAllowedInForInStatement(#[label] pub Span);
+
+#[derive(Debug, Error, Diagnostic)]
+#[error("The left-hand side of a for...in statement cannot be an using declaration.")]
+#[diagnostic()]
+pub struct UsingDeclarationNotAllowedInForInStatement(#[label] pub Span);
+
+#[derive(Debug, Error, Diagnostic)]
+#[error("Using declarations must have an initializer.")]
+#[diagnostic()]
+pub struct UsingDeclarationsMustBeInitialized(#[label] pub Span);