feat(isolated-declarations): report error for expando functions

crates/oxc_isolated_declarations/src/diagnostics.rs

@@ -112,7 +112,6 @@ pub fn implicitly_adding_undefined_to_type(span: Span) -> OxcDiagnostic {
     .with_label(span)
 }
 
-#[allow(dead_code)]
 pub fn function_with_assigning_properties(span: Span) -> OxcDiagnostic {
     OxcDiagnostic::error(
         "TS9023: Assigning properties to functions without declaring them is not supported with --isolatedDeclarations. Add an explicit declaration for the properties assigned to this function.",

crates/oxc_isolated_declarations/src/lib.rs

@@ -19,11 +19,13 @@ mod types;
 
 use std::{cell::RefCell, collections::VecDeque, mem};
 
+use diagnostics::function_with_assigning_properties;
 use oxc_allocator::Allocator;
 #[allow(clippy::wildcard_imports)]
 use oxc_ast::{ast::*, AstBuilder, Visit};
 use oxc_diagnostics::OxcDiagnostic;
 use oxc_span::{Atom, SourceType, SPAN};
+use rustc_hash::FxHashSet;
 
 use crate::scope::ScopeTree;
 
@@ -95,6 +97,8 @@ impl<'a> IsolatedDeclarations<'a> {
         &mut self,
         stmts: &oxc_allocator::Vec<'a, Statement<'a>>,
     ) -> oxc_allocator::Vec<'a, Statement<'a>> {
+        self.report_error_for_expando_function(stmts);
+
         let mut new_ast_stmts = self.ast.new_vec::<Statement<'a>>();
         for stmt in Self::remove_function_overloads_implementation(self.ast.copy(stmts)) {
             if let Some(decl) = stmt.as_declaration() {
@@ -112,13 +116,16 @@ impl<'a> IsolatedDeclarations<'a> {
         &mut self,
         stmts: &oxc_allocator::Vec<'a, Statement<'a>>,
     ) -> oxc_allocator::Vec<'a, Statement<'a>> {
+        self.report_error_for_expando_function(stmts);
+
         // https://github.com/microsoft/TypeScript/pull/58912
         let mut need_empty_export_marker = true;
 
         let mut new_stmts = Vec::new();
         let mut variables_declarations = VecDeque::new();
         let mut variable_transformed_indexes = VecDeque::new();
         let mut transformed_indexes = Vec::new();
+
         // 1. Collect all declarations, module declarations
         // 2. Transform export declarations
         // 3. Collect all bindings / reference from module declarations
@@ -393,6 +400,81 @@ impl<'a> IsolatedDeclarations<'a> {
         })
     }
 
+    pub fn report_error_for_expando_function(&self, stmts: &oxc_allocator::Vec<'a, Statement<'a>>) {
+        let mut can_expando_function_names = FxHashSet::default();
+        for stmt in stmts {
+            match stmt {
+                Statement::ExportNamedDeclaration(decl) => match decl.declaration.as_ref() {
+                    Some(Declaration::FunctionDeclaration(func)) => {
+                        if func.body.is_some() {
+                            if let Some(id) = func.id.as_ref() {
+                                can_expando_function_names.insert(id.name.clone());
+                            }
+                        }
+                    }
+                    Some(Declaration::VariableDeclaration(decl)) => {
+                        for declarator in &decl.declarations {
+                            if declarator.id.type_annotation.is_none()
+                                && declarator.init.as_ref().is_some_and(Expression::is_function)
+                            {
+                                if let Some(name) = declarator.id.get_identifier() {
+                                    can_expando_function_names.insert(name.clone());
+                                }
+                            }
+                        }
+                    }
+                    _ => (),
+                },
+                Statement::ExportDefaultDeclaration(decl) => {
+                    if let ExportDefaultDeclarationKind::FunctionDeclaration(func) =
+                        &decl.declaration
+                    {
+                        if func.body.is_some() {
+                            if let Some(id) = func.id.as_ref() {
+                                can_expando_function_names.insert(id.name.clone());
+                            }
+                        }
+                    }
+                }
+                Statement::FunctionDeclaration(func) => {
+                    if func.body.is_some() {
+                        if let Some(id) = func.id.as_ref() {
+                            can_expando_function_names.insert(id.name.clone());
+                        }
+                    }
+                }
+                Statement::VariableDeclaration(decl) => {
+                    for declarator in &decl.declarations {
+                        if declarator.id.type_annotation.is_none()
+                            && declarator.init.as_ref().is_some_and(Expression::is_function)
+                        {
+                            if let Some(name) = declarator.id.get_identifier() {
+                                can_expando_function_names.insert(name.clone());
+                            }
+                        }
+                    }
+                }
+                Statement::ExpressionStatement(stmt) => {
+                    if let Expression::AssignmentExpression(assignment) = &stmt.expression {
+                        if let AssignmentTarget::StaticMemberExpression(static_member_expr) =
+                            &assignment.left
+                        {
+                            if let Expression::Identifier(ident) = &static_member_expr.object {
+                                if can_expando_function_names.contains(&ident.name) {
+                                    self.error(function_with_assigning_properties(
+                                        static_member_expr.span,
+                                    ));
+                                }
+                            }
+                        }
+                    }
+                }
+
+                _ => {}
+            }
+        }
+    }
+
     pub fn is_declare(&self) -> bool {
         // If we are in a module block, we don't need to add declare
         !self.scope.is_ts_module_block_flag()

crates/oxc_isolated_declarations/tests/fixtures/expando-function.ts

@@ -0,0 +1,28 @@
+export function foo(): void {}
+foo.apply = () => {}
+foo.call = ()=> {}
+foo.bind = ()=> {}
+foo.caller = ()=> {}
+foo.toString = ()=> {}
+foo.length = 10
+foo.length = 10
+
+export const bar = (): void => {}
+bar.apply = () => {}
+bar.call = ()=> {}
+bar.bind = ()=> {}
+bar.caller = ()=> {}
+bar.toString = ()=> {}
+bar.length = 10
+bar.length = 10
+
+export namespace NS {
+  export const bar = (): void => {}
+  bar.apply = () => {}
+  bar.call = ()=> {}
+  bar.bind = ()=> {}
+  bar.caller = ()=> {}
+  bar.toString = ()=> {}
+  bar.length = 10
+  bar.length = 10
+}

crates/oxc_isolated_declarations/tests/snapshots/expando-function.snap

@@ -0,0 +1,224 @@
+---
+source: crates/oxc_isolated_declarations/tests/mod.rs
+input_file: crates/oxc_isolated_declarations/tests/fixtures/expando-function.ts
+---
+==================== .D.TS ====================
+
+export declare function foo(): void;
+export declare const bar: () => void;
+export declare module NS {
+	export const bar: () => void;
+}
+
+
+==================== Errors ====================
+
+  x TS9023: Assigning properties to functions without declaring them is not
+  | supported with --isolatedDeclarations. Add an explicit declaration for the
+  | properties assigned to this function.
+   ,-[7:1]
+ 6 | export function foo(): void {}
+ 7 | foo.apply = () => {}
+   : ^^^^^^^^^
+ 8 | foo.call = ()=> {}
+   `----
+
+  x TS9023: Assigning properties to functions without declaring them is not
+  | supported with --isolatedDeclarations. Add an explicit declaration for the
+  | properties assigned to this function.
+   ,-[8:1]
+ 7 | foo.apply = () => {}
+ 8 | foo.call = ()=> {}
+   : ^^^^^^^^
+ 9 | foo.bind = ()=> {}
+   `----
+
+  x TS9023: Assigning properties to functions without declaring them is not
+  | supported with --isolatedDeclarations. Add an explicit declaration for the
+  | properties assigned to this function.
+    ,-[9:1]
+  8 | foo.call = ()=> {}
+  9 | foo.bind = ()=> {}
+    : ^^^^^^^^
+ 10 | foo.caller = ()=> {}
+    `----
+
+  x TS9023: Assigning properties to functions without declaring them is not
+  | supported with --isolatedDeclarations. Add an explicit declaration for the
+  | properties assigned to this function.
+    ,-[10:1]
+  9 | foo.bind = ()=> {}
+ 10 | foo.caller = ()=> {}
+    : ^^^^^^^^^^
+ 11 | foo.toString = ()=> {}
+    `----
+
+  x TS9023: Assigning properties to functions without declaring them is not
+  | supported with --isolatedDeclarations. Add an explicit declaration for the
+  | properties assigned to this function.
+    ,-[11:1]
+ 10 | foo.caller = ()=> {}
+ 11 | foo.toString = ()=> {}
+    : ^^^^^^^^^^^^
+ 12 | foo.length = 10
+    `----
+
+  x TS9023: Assigning properties to functions without declaring them is not
+  | supported with --isolatedDeclarations. Add an explicit declaration for the
+  | properties assigned to this function.
+    ,-[12:1]
+ 11 | foo.toString = ()=> {}
+ 12 | foo.length = 10
+    : ^^^^^^^^^^
+ 13 | foo.length = 10
+    `----
+
+  x TS9023: Assigning properties to functions without declaring them is not
+  | supported with --isolatedDeclarations. Add an explicit declaration for the
+  | properties assigned to this function.
+    ,-[13:1]
+ 12 | foo.length = 10
+ 13 | foo.length = 10
+    : ^^^^^^^^^^
+ 14 | 
+    `----
+
+  x TS9023: Assigning properties to functions without declaring them is not
+  | supported with --isolatedDeclarations. Add an explicit declaration for the
+  | properties assigned to this function.
+    ,-[16:1]
+ 15 | export const bar = (): void => {}
+ 16 | bar.apply = () => {}
+    : ^^^^^^^^^
+ 17 | bar.call = ()=> {}
+    `----
+
+  x TS9023: Assigning properties to functions without declaring them is not
+  | supported with --isolatedDeclarations. Add an explicit declaration for the
+  | properties assigned to this function.
+    ,-[17:1]
+ 16 | bar.apply = () => {}
+ 17 | bar.call = ()=> {}
+    : ^^^^^^^^
+ 18 | bar.bind = ()=> {}
+    `----
+
+  x TS9023: Assigning properties to functions without declaring them is not
+  | supported with --isolatedDeclarations. Add an explicit declaration for the
+  | properties assigned to this function.
+    ,-[18:1]
+ 17 | bar.call = ()=> {}
+ 18 | bar.bind = ()=> {}
+    : ^^^^^^^^
+ 19 | bar.caller = ()=> {}
+    `----
+
+  x TS9023: Assigning properties to functions without declaring them is not
+  | supported with --isolatedDeclarations. Add an explicit declaration for the
+  | properties assigned to this function.
+    ,-[19:1]
+ 18 | bar.bind = ()=> {}
+ 19 | bar.caller = ()=> {}
+    : ^^^^^^^^^^
+ 20 | bar.toString = ()=> {}
+    `----
+
+  x TS9023: Assigning properties to functions without declaring them is not
+  | supported with --isolatedDeclarations. Add an explicit declaration for the
+  | properties assigned to this function.
+    ,-[20:1]
+ 19 | bar.caller = ()=> {}
+ 20 | bar.toString = ()=> {}
+    : ^^^^^^^^^^^^
+ 21 | bar.length = 10
+    `----
+
+  x TS9023: Assigning properties to functions without declaring them is not
+  | supported with --isolatedDeclarations. Add an explicit declaration for the
+  | properties assigned to this function.
+    ,-[21:1]
+ 20 | bar.toString = ()=> {}
+ 21 | bar.length = 10
+    : ^^^^^^^^^^
+ 22 | bar.length = 10
+    `----
+
+  x TS9023: Assigning properties to functions without declaring them is not
+  | supported with --isolatedDeclarations. Add an explicit declaration for the
+  | properties assigned to this function.
+    ,-[22:1]
+ 21 | bar.length = 10
+ 22 | bar.length = 10
+    : ^^^^^^^^^^
+ 23 | 
+    `----
+
+  x TS9023: Assigning properties to functions without declaring them is not
+  | supported with --isolatedDeclarations. Add an explicit declaration for the
+  | properties assigned to this function.
+    ,-[26:3]
+ 25 |   export const bar = (): void => {}
+ 26 |   bar.apply = () => {}
+    :   ^^^^^^^^^
+ 27 |   bar.call = ()=> {}
+    `----
+
+  x TS9023: Assigning properties to functions without declaring them is not
+  | supported with --isolatedDeclarations. Add an explicit declaration for the
+  | properties assigned to this function.
+    ,-[27:3]
+ 26 |   bar.apply = () => {}
+ 27 |   bar.call = ()=> {}
+    :   ^^^^^^^^
+ 28 |   bar.bind = ()=> {}
+    `----
+
+  x TS9023: Assigning properties to functions without declaring them is not
+  | supported with --isolatedDeclarations. Add an explicit declaration for the
+  | properties assigned to this function.
+    ,-[28:3]
+ 27 |   bar.call = ()=> {}
+ 28 |   bar.bind = ()=> {}
+    :   ^^^^^^^^
+ 29 |   bar.caller = ()=> {}
+    `----
+
+  x TS9023: Assigning properties to functions without declaring them is not
+  | supported with --isolatedDeclarations. Add an explicit declaration for the
+  | properties assigned to this function.
+    ,-[29:3]
+ 28 |   bar.bind = ()=> {}
+ 29 |   bar.caller = ()=> {}
+    :   ^^^^^^^^^^
+ 30 |   bar.toString = ()=> {}
+    `----
+
+  x TS9023: Assigning properties to functions without declaring them is not
+  | supported with --isolatedDeclarations. Add an explicit declaration for the
+  | properties assigned to this function.
+    ,-[30:3]
+ 29 |   bar.caller = ()=> {}
+ 30 |   bar.toString = ()=> {}
+    :   ^^^^^^^^^^^^
+ 31 |   bar.length = 10
+    `----
+
+  x TS9023: Assigning properties to functions without declaring them is not
+  | supported with --isolatedDeclarations. Add an explicit declaration for the
+  | properties assigned to this function.
+    ,-[31:3]
+ 30 |   bar.toString = ()=> {}
+ 31 |   bar.length = 10
+    :   ^^^^^^^^^^
+ 32 |   bar.length = 10
+    `----
+
+  x TS9023: Assigning properties to functions without declaring them is not
+  | supported with --isolatedDeclarations. Add an explicit declaration for the
+  | properties assigned to this function.
+    ,-[32:3]
+ 31 |   bar.length = 10
+ 32 |   bar.length = 10
+    :   ^^^^^^^^^^
+ 33 | }
+    `----