From bf515e29b810e5794d4be71e5ed65276106fed86 Mon Sep 17 00:00:00 2001
From: Boshen <boshenc@gmail.com>
Date: Fri, 23 Jan 2026 22:04:38 +0800
Subject: [PATCH] feat(parser): support top-level await detection in
 unambiguous mode

Add support for detecting ES modules via top-level await in unambiguous
parsing mode, conforming with Babel's behavior.

In unambiguous mode, when `await <expr>` is encountered at the top level
and the expression is unambiguous (not an ambiguous token), the file is
detected as an ES module.

Ambiguous tokens after `await` that don't definitively indicate ESM:
- `+`, `-` (unary vs binary operators)
- `(`, `[` (call/member vs grouped expression)
- `/` (regex vs division)
- `%` (modulo operator)
- `;` (semicolon - empty await)
- Template literals
- `of`, `using` (contextual keywords)
- Newlines (ASI boundary)

Also fixes Script mode parsing where `await` at top level should always
be an identifier (not a keyword), preventing `await / 0 / u` from being
incorrectly parsed as `await /0/u` (await + regex).

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
---
 ..._prefer_logical_operator_over_ternary.snap | 19 ++---
 .../unicorn_prefer_node_protocol.snap         |  8 +-
 crates/oxc_parser/src/js/expression.rs        |  7 +-
 crates/oxc_parser/src/js/statement.rs         | 74 +++++++++++++++++++
 crates/oxc_parser/src/module_record.rs        |  8 ++
 tasks/coverage/snapshots/codegen_babel.snap   |  4 +-
 tasks/coverage/snapshots/formatter_babel.snap |  4 +-
 tasks/coverage/snapshots/minifier_babel.snap  |  4 +-
 tasks/coverage/snapshots/parser_babel.snap    | 62 +++++++---------
 tasks/coverage/snapshots/parser_misc.snap     |  8 +-
 .../coverage/snapshots/parser_typescript.snap | 21 +-----
 tasks/coverage/snapshots/semantic_babel.snap  |  4 +-
 .../coverage/snapshots/transformer_babel.snap |  4 +-
 .../coverage/snapshots/transformer_misc.snap  |  4 +-
 .../snapshots/transformer_typescript.snap     | 18 ++++-
 tasks/coverage/src/babel/mod.rs               |  2 -
 tasks/coverage/src/driver.rs                  |  3 +
 tasks/coverage/src/tools/minifier.rs          | 15 +++-
 tasks/coverage/src/tools/transformer.rs       |  6 +-
 19 files changed, 180 insertions(+), 95 deletions(-)

diff --git a/crates/oxc_linter/src/snapshots/unicorn_prefer_logical_operator_over_ternary.snap b/crates/oxc_linter/src/snapshots/unicorn_prefer_logical_operator_over_ternary.snap
index b13daeaf1659a..f0d9cd1f4cc88 100644
--- a/crates/oxc_linter/src/snapshots/unicorn_prefer_logical_operator_over_ternary.snap
+++ b/crates/oxc_linter/src/snapshots/unicorn_prefer_logical_operator_over_ternary.snap
@@ -99,26 +99,19 @@ source: crates/oxc_linter/src/tester.rs
    ╰────
   help: Either remove this `await` or add the `async` keyword to the enclosing function
 
-  × `await` is only allowed within async functions and at the top levels of modules
+  ⚠ eslint-plugin-unicorn(prefer-logical-operator-over-ternary): Prefer using a logical operator over a ternary.
    ╭─[prefer_logical_operator_over_ternary.tsx:1:1]
  1 │ await a ? await a : foo
-   · ─────
-   ╰────
-  help: Either remove this `await` or add the `async` keyword to the enclosing function
-
-  × `await` is only allowed within async functions and at the top levels of modules
-   ╭─[prefer_logical_operator_over_ternary.tsx:1:11]
- 1 │ await a ? await a : foo
-   ·           ─────
+   · ───────────────────────
    ╰────
-  help: Either remove this `await` or add the `async` keyword to the enclosing function
+  help: Switch to "||" or "??" operator
 
-  × `await` is only allowed within async functions and at the top levels of modules
+  ⚠ eslint-plugin-unicorn(prefer-logical-operator-over-ternary): Prefer using a logical operator over a ternary.
    ╭─[prefer_logical_operator_over_ternary.tsx:1:1]
  1 │ await a ? (await (a)) : (foo)
-   · ─────
+   · ─────────────────────────────
    ╰────
-  help: Either remove this `await` or add the `async` keyword to the enclosing function
+  help: Switch to "||" or "??" operator
 
   × `await` is only allowed within async functions and at the top levels of modules
    ╭─[prefer_logical_operator_over_ternary.tsx:1:2]
diff --git a/crates/oxc_linter/src/snapshots/unicorn_prefer_node_protocol.snap b/crates/oxc_linter/src/snapshots/unicorn_prefer_node_protocol.snap
index 3fba1c243fe13..bb946d03f5eac 100644
--- a/crates/oxc_linter/src/snapshots/unicorn_prefer_node_protocol.snap
+++ b/crates/oxc_linter/src/snapshots/unicorn_prefer_node_protocol.snap
@@ -105,9 +105,9 @@ source: crates/oxc_linter/src/tester.rs
    ·        ──
    ╰────
 
-  × `await` is only allowed within async functions and at the top levels of modules
-   ╭─[prefer_node_protocol.tsx:1:1]
+  ⚠ eslint-plugin-unicorn(prefer-node-protocol): Prefer using the `node:` protocol when importing Node.js builtin modules.
+   ╭─[prefer_node_protocol.tsx:1:14]
  1 │ await import('assert/strict')
-   · ─────
+   ·              ───────────────
    ╰────
-  help: Either remove this `await` or add the `async` keyword to the enclosing function
+  help: Prefer `node:assert/strict` over `assert/strict`.
diff --git a/crates/oxc_parser/src/js/expression.rs b/crates/oxc_parser/src/js/expression.rs
index 143e14dd10d48..51d511b8ca120 100644
--- a/crates/oxc_parser/src/js/expression.rs
+++ b/crates/oxc_parser/src/js/expression.rs
@@ -1476,7 +1476,7 @@ impl<'a> ParserImpl<'a> {
 
     /// ``AwaitExpression`[Yield]` :
     ///     await `UnaryExpression`[?Yield, +Await]
-    fn parse_await_expression(&mut self, lhs_span: u32) -> Expression<'a> {
+    pub(crate) fn parse_await_expression(&mut self, lhs_span: u32) -> Expression<'a> {
         let span = self.start_span();
         if !self.ctx.has_await() {
             // For `ModuleKind::Unambiguous`, defer the error until we know whether
@@ -1542,6 +1542,11 @@ impl<'a> ParserImpl<'a> {
             if self.ctx.has_await() {
                 return true;
             }
+            // In Script mode (not module, not unambiguous), `await` at top level is just an identifier.
+            // Only check lookahead for Module (top-level await) or Unambiguous mode (detection).
+            if !self.source_type.is_module() && !self.source_type.is_unambiguous() {
+                return false;
+            }
             return self.lookahead(|p| {
                 Self::next_token_is_identifier_or_keyword_or_literal_on_same_line(p, true)
             });
diff --git a/crates/oxc_parser/src/js/statement.rs b/crates/oxc_parser/src/js/statement.rs
index e84e34d75a252..d214043500885 100644
--- a/crates/oxc_parser/src/js/statement.rs
+++ b/crates/oxc_parser/src/js/statement.rs
@@ -155,6 +155,13 @@ impl<'a> ParserImpl<'a> {
             Kind::Const => self.parse_const_statement(stmt_ctx),
             Kind::Using if self.is_using_declaration() => self.parse_using_statement(stmt_ctx),
             Kind::Await if self.is_using_statement() => self.parse_using_statement(stmt_ctx),
+            Kind::Await
+                if stmt_ctx.is_top_level()
+                    && self.source_type.is_unambiguous()
+                    && self.is_unambiguous_await_statement() =>
+            {
+                self.parse_await_statement()
+            }
             Kind::Interface
             | Kind::Type
             | Kind::Module
@@ -234,6 +241,73 @@ impl<'a> ParserImpl<'a> {
         self.parse_expression_statement(span, expr)
     }
 
+    /// Check if `await` starts an unambiguous await statement.
+    ///
+    /// Returns true if:
+    /// - We're at `await`
+    /// - Not in await context (not already in async/module)
+    /// - Next token is NOT ambiguous (not +, -, (, [, /, template, of, using, newline)
+    ///
+    /// This is used in unambiguous mode to detect that `await expr` at top level
+    /// definitively makes this file an ES module.
+    pub(crate) fn is_unambiguous_await_statement(&mut self) -> bool {
+        debug_assert!(self.at(Kind::Await));
+        if self.ctx.has_await() {
+            return false;
+        }
+        self.lookahead(Self::peek_is_unambiguous_await_argument)
+    }
+
+    /// Check if the token following `await` is unambiguous (not ambiguous).
+    ///
+    /// Ambiguous tokens are those that could produce different ASTs depending on whether
+    /// the file is parsed as a script or module:
+    /// - Line break: `await\n0` could be two expression statements
+    /// - `+` / `-`: `await + 0` could be binary expression or await of unary
+    /// - `(`: `await(0)` could be call expression or await of parenthesized
+    /// - `[`: `await[0]` could be member expression or await of array
+    /// - `/`: `await /x/` could be division or await of regex
+    /// - Template: `await\`\`` could be tagged template or await of template
+    /// - `of`: `for (await of [])` ambiguity
+    /// - `using`: `await using` has special declaration semantics
+    /// - `%`: `await %x(0)` is always modulo in script mode (`await % x(0)`)
+    /// - `;`: `await;` is identifier statement, not await expression (await needs argument)
+    fn peek_is_unambiguous_await_argument(&mut self) -> bool {
+        self.bump_any(); // skip `await`
+        let token = self.cur_token();
+        if token.is_on_new_line() {
+            return false;
+        }
+        !matches!(
+            token.kind(),
+            Kind::Plus
+                | Kind::Minus
+                | Kind::LParen
+                | Kind::LBrack
+                | Kind::Slash
+                | Kind::Percent
+                | Kind::Semicolon
+                | Kind::TemplateHead
+                | Kind::NoSubstitutionTemplate
+                | Kind::Of
+                | Kind::Using
+        )
+    }
+
+    /// Parse a top-level await statement in unambiguous mode.
+    ///
+    /// This marks the file as ESM (since unambiguous await proves this is a module)
+    /// and parses the full expression (which starts with await) as an expression statement.
+    pub(crate) fn parse_await_statement(&mut self) -> Statement<'a> {
+        let span = self.start_span();
+        // Mark as ESM - unambiguous await proves this is a module
+        self.module_record_builder.found_unambiguous_await();
+        // Enable await context and parse the full expression (not just the await part)
+        // This handles cases like `await a ? b : c` where the await is part of a larger expression
+        let expr = self.context_add(Context::Await, Self::parse_expr);
+        self.parse_expression_statement(span, expr)
+    }
+
     /// Section 14.2 Block Statement
     pub(crate) fn parse_block(&mut self) -> Box<'a, BlockStatement<'a>> {
         let span = self.start_span();
diff --git a/crates/oxc_parser/src/module_record.rs b/crates/oxc_parser/src/module_record.rs
index 190efdb4f217c..4315cf0d8d065 100644
--- a/crates/oxc_parser/src/module_record.rs
+++ b/crates/oxc_parser/src/module_record.rs
@@ -199,6 +199,14 @@ impl<'a> ModuleRecordBuilder<'a> {
         self.module_record.import_metas.push(span);
     }
 
+    /// Mark as ESM when an unambiguous top-level await is encountered.
+    ///
+    /// In unambiguous mode, `await expr` where `expr` is clearly an expression (not ambiguous
+    /// like `+`, `-`, `(`, `[`, etc.) indicates this is definitely an ES module.
+    pub fn found_unambiguous_await(&mut self) {
+        self.module_record.has_module_syntax = true;
+    }
+
     pub fn visit_import_declaration(&mut self, decl: &ImportDeclaration<'a>) {
         let module_request = NameSpan::new(decl.source.value, decl.source.span);
 
diff --git a/tasks/coverage/snapshots/codegen_babel.snap b/tasks/coverage/snapshots/codegen_babel.snap
index 12a521286905c..bf07f99da066d 100644
--- a/tasks/coverage/snapshots/codegen_babel.snap
+++ b/tasks/coverage/snapshots/codegen_babel.snap
@@ -1,5 +1,5 @@
 commit: 6ef16ca4
 
 codegen_babel Summary:
-AST Parsed     : 2221/2221 (100.00%)
-Positive Passed: 2221/2221 (100.00%)
+AST Parsed     : 2225/2225 (100.00%)
+Positive Passed: 2225/2225 (100.00%)
diff --git a/tasks/coverage/snapshots/formatter_babel.snap b/tasks/coverage/snapshots/formatter_babel.snap
index dea32d16444af..2a0462c1f049b 100644
--- a/tasks/coverage/snapshots/formatter_babel.snap
+++ b/tasks/coverage/snapshots/formatter_babel.snap
@@ -1,8 +1,8 @@
 commit: 6ef16ca4
 
 formatter_babel Summary:
-AST Parsed     : 2221/2221 (100.00%)
-Positive Passed: 2215/2221 (99.73%)
+AST Parsed     : 2225/2225 (100.00%)
+Positive Passed: 2219/2225 (99.73%)
 Mismatch: tasks/coverage/babel/packages/babel-parser/test/fixtures/comments/basic/async-arrow-function/input.js
 
 Mismatch: tasks/coverage/babel/packages/babel-parser/test/fixtures/comments/basic/class-method/input.js
diff --git a/tasks/coverage/snapshots/minifier_babel.snap b/tasks/coverage/snapshots/minifier_babel.snap
index 2b4b0820d8cf5..40a84c7186418 100644
--- a/tasks/coverage/snapshots/minifier_babel.snap
+++ b/tasks/coverage/snapshots/minifier_babel.snap
@@ -1,5 +1,5 @@
 commit: 6ef16ca4
 
 minifier_babel Summary:
-AST Parsed     : 1783/1783 (100.00%)
-Positive Passed: 1783/1783 (100.00%)
+AST Parsed     : 1787/1787 (100.00%)
+Positive Passed: 1787/1787 (100.00%)
diff --git a/tasks/coverage/snapshots/parser_babel.snap b/tasks/coverage/snapshots/parser_babel.snap
index 84301aaa98337..c643a1ab30766 100644
--- a/tasks/coverage/snapshots/parser_babel.snap
+++ b/tasks/coverage/snapshots/parser_babel.snap
@@ -1,8 +1,8 @@
 commit: 6ef16ca4
 
 parser_babel Summary:
-AST Parsed     : 2217/2221 (99.82%)
-Positive Passed: 2204/2221 (99.23%)
+AST Parsed     : 2221/2225 (99.82%)
+Positive Passed: 2208/2225 (99.24%)
 Negative Passed: 1654/1689 (97.93%)
 Expect Syntax Error: tasks/coverage/babel/packages/babel-parser/test/fixtures/es2026/explicit-resource-management/invalid-for-using-of-no-initializer/input.js
 
@@ -1186,12 +1186,12 @@ Expect to Parse: tasks/coverage/babel/packages/babel-parser/test/fixtures/typesc
    ╰────
   help: In strict mode code, functions can only be declared at top level or inside a block
 
-  × `await` is only allowed within async functions and at the top levels of modules
-   ╭─[babel/packages/babel-parser/test/fixtures/core/sourcetype-commonjs/invalid-top-level-await/input.js:1:1]
+  × Expected a semicolon or an implicit semicolon after a statement, but found none
+   ╭─[babel/packages/babel-parser/test/fixtures/core/sourcetype-commonjs/invalid-top-level-await/input.js:1:6]
  1 │ await Promise.resolve();
-   · ─────
+   ·      ▲
    ╰────
-  help: Either remove this `await` or add the `async` keyword to the enclosing function
+  help: Try inserting a semicolon here
 
   × A 'yield' expression is only allowed in a generator body.
    ╭─[babel/packages/babel-parser/test/fixtures/core/sourcetype-commonjs/invalid-top-level-yield/input.js:1:1]
@@ -5128,21 +5128,21 @@ Expect to Parse: tasks/coverage/babel/packages/babel-parser/test/fixtures/typesc
    ╰────
   help: Try inserting a semicolon here
 
-  × `await` is only allowed within async functions and at the top levels of modules
-   ╭─[babel/packages/babel-parser/test/fixtures/es2017/async-functions/9/input.js:1:25]
+  × Expected a semicolon or an implicit semicolon after a statement, but found none
+   ╭─[babel/packages/babel-parser/test/fixtures/es2017/async-functions/9/input.js:1:30]
  1 │ function foo(promise) { await promise; }
-   ·                         ─────
+   ·                              ▲
    ╰────
-  help: Either remove this `await` or add the `async` keyword to the enclosing function
+  help: Try inserting a semicolon here
 
-  × `await` is only allowed within async functions and at the top levels of modules
-   ╭─[babel/packages/babel-parser/test/fixtures/es2017/async-functions/allow-await-outside-function-throw/input.js:2:10]
+  × Expected a semicolon or an implicit semicolon after a statement, but found none
+   ╭─[babel/packages/babel-parser/test/fixtures/es2017/async-functions/allow-await-outside-function-throw/input.js:2:15]
  1 │ function a() {
  2 │   return await 1
-   ·          ─────
+   ·               ▲
  3 │ }
    ╰────
-  help: Either remove this `await` or add the `async` keyword to the enclosing function
+  help: Try inserting a semicolon here
 
   × Cannot use `await` as an identifier in an async context
    ╭─[babel/packages/babel-parser/test/fixtures/es2017/async-functions/async-await-as-arrow-binding-identifier/input.js:1:7]
@@ -5186,12 +5186,12 @@ Expect to Parse: tasks/coverage/babel/packages/babel-parser/test/fixtures/typesc
  3 │ }
    ╰────
 
-  × `await` is only allowed within async functions and at the top levels of modules
-   ╭─[babel/packages/babel-parser/test/fixtures/es2017/async-functions/await-inside-arrow-expression-disallowed/input.js:1:9]
+  × Expected a semicolon or an implicit semicolon after a statement, but found none
+   ╭─[babel/packages/babel-parser/test/fixtures/es2017/async-functions/await-inside-arrow-expression-disallowed/input.js:1:14]
  1 │ () => { await x }
-   ·         ─────
+   ·              ▲
    ╰────
-  help: Either remove this `await` or add the `async` keyword to the enclosing function
+  help: Try inserting a semicolon here
 
   × await expression not allowed in formal parameter
    ╭─[babel/packages/babel-parser/test/fixtures/es2017/async-functions/await-inside-parameters/input.js:1:23]
@@ -5225,21 +5225,13 @@ Expect to Parse: tasks/coverage/babel/packages/babel-parser/test/fixtures/typesc
  3 │ }
    ╰────
 
-  × `await` is only allowed within async functions and at the top levels of modules
-   ╭─[babel/packages/babel-parser/test/fixtures/es2017/async-functions/await-inside-parameters-of-nested-function/input.js:2:20]
+  × Expected `,` or `)` but found `decimal`
+   ╭─[babel/packages/babel-parser/test/fixtures/es2017/async-functions/await-inside-parameters-of-nested-function/input.js:2:26]
  1 │ async function foo() {
  2 │   function bar(x = await 2) {}
-   ·                    ─────
- 3 │ }
-   ╰────
-  help: Either remove this `await` or add the `async` keyword to the enclosing function
-
-  × await expression not allowed in formal parameter
-   ╭─[babel/packages/babel-parser/test/fixtures/es2017/async-functions/await-inside-parameters-of-nested-function/input.js:2:20]
- 1 │ async function foo() {
- 2 │   function bar(x = await 2) {}
-   ·                    ───┬───
-   ·                       ╰── await expression not allowed in formal parameter
+   ·               ┬          ┬
+   ·               │          ╰── `,` or `)` expected
+   ·               ╰── Opened here
  3 │ }
    ╰────
 
@@ -8422,12 +8414,12 @@ Expect to Parse: tasks/coverage/babel/packages/babel-parser/test/fixtures/typesc
    ╰────
   help: Either remove this `await` or add the `async` keyword to the enclosing function
 
-  × `await` is only allowed within async functions and at the top levels of modules
-   ╭─[babel/packages/babel-parser/test/fixtures/es2022/top-level-await-script/top-level/input.js:1:1]
+  × Expected a semicolon or an implicit semicolon after a statement, but found none
+   ╭─[babel/packages/babel-parser/test/fixtures/es2022/top-level-await-script/top-level/input.js:1:6]
  1 │ await 0;
-   · ─────
+   ·      ▲
    ╰────
-  help: Either remove this `await` or add the `async` keyword to the enclosing function
+  help: Try inserting a semicolon here
 
   × Invalid regular expression: Invalid unicode flags combination `u` and `v`
    ╭─[babel/packages/babel-parser/test/fixtures/es2024/regexp-unicode-sets/uv-error/input.js:1:6]
diff --git a/tasks/coverage/snapshots/parser_misc.snap b/tasks/coverage/snapshots/parser_misc.snap
index ebce7d0fa0695..87344ce7a63a5 100644
--- a/tasks/coverage/snapshots/parser_misc.snap
+++ b/tasks/coverage/snapshots/parser_misc.snap
@@ -72,13 +72,13 @@ Negative Passed: 131/131 (100.00%)
    · ──────
    ╰────
 
-  × `await` is only allowed within async functions and at the top levels of modules
-   ╭─[misc/fail/commonjs-top-level-await.cjs:2:1]
+  × Expected a semicolon or an implicit semicolon after a statement, but found none
+   ╭─[misc/fail/commonjs-top-level-await.cjs:2:6]
  1 │ // CommonJS does NOT allow top-level await (only ES modules do)
  2 │ await Promise.resolve();
-   · ─────
+   ·      ▲
    ╰────
-  help: Either remove this `await` or add the `async` keyword to the enclosing function
+  help: Try inserting a semicolon here
 
   × Encountered diff marker
     ╭─[misc/fail/diff-markers.js:10:1]
diff --git a/tasks/coverage/snapshots/parser_typescript.snap b/tasks/coverage/snapshots/parser_typescript.snap
index 2c4bd01801704..62b864544b07e 100644
--- a/tasks/coverage/snapshots/parser_typescript.snap
+++ b/tasks/coverage/snapshots/parser_typescript.snap
@@ -3,7 +3,7 @@ commit: 7f6a8467
 parser_typescript Summary:
 AST Parsed     : 9842/9843 (99.99%)
 Positive Passed: 9837/9843 (99.94%)
-Negative Passed: 1500/2555 (58.71%)
+Negative Passed: 1499/2555 (58.67%)
 Expect Syntax Error: tasks/coverage/typescript/tests/cases/compiler/FunctionDeclaration3.ts
 
 Expect Syntax Error: tasks/coverage/typescript/tests/cases/compiler/FunctionDeclaration4.ts
@@ -1484,6 +1484,8 @@ Expect Syntax Error: tasks/coverage/typescript/tests/cases/conformance/externalM
 
 Expect Syntax Error: tasks/coverage/typescript/tests/cases/conformance/externalModules/rewriteRelativeImportExtensions/emit.ts
 
+Expect Syntax Error: tasks/coverage/typescript/tests/cases/conformance/externalModules/topLevelAwaitNonModule.ts
+
 Expect Syntax Error: tasks/coverage/typescript/tests/cases/conformance/externalModules/topLevelModuleDeclarationAndFile.ts
 
 Expect Syntax Error: tasks/coverage/typescript/tests/cases/conformance/externalModules/typeOnly/chained2.ts
@@ -19784,23 +19786,6 @@ Expect to Parse: tasks/coverage/typescript/tests/cases/conformance/statements/Va
    ·          ─────
    ╰────
 
-  × `await` is only allowed within async functions and at the top levels of modules
-   ╭─[typescript/tests/cases/conformance/externalModules/topLevelAwaitNonModule.ts:1:1]
- 1 │ await x;
-   · ─────
- 2 │ 
-   ╰────
-  help: Either remove this `await` or add the `async` keyword to the enclosing function
-
-  × `await` is only allowed within async functions and at the top levels of modules
-   ╭─[typescript/tests/cases/conformance/externalModules/topLevelAwaitNonModule.ts:5:5]
- 4 │ 
- 5 │ for await (const item of arr) {
-   ·     ─────
- 6 │   item;
-   ╰────
-  help: Either remove this `await` or add the `async` keyword to the enclosing function
-
   × Expected `=` but found `;`
     ╭─[typescript/tests/cases/conformance/externalModules/typeOnly/exportDeclaration_missingBraces.ts:11:16]
  10 │ namespace ns {
diff --git a/tasks/coverage/snapshots/semantic_babel.snap b/tasks/coverage/snapshots/semantic_babel.snap
index 6bace7e0ffe46..c48e7ff589d96 100644
--- a/tasks/coverage/snapshots/semantic_babel.snap
+++ b/tasks/coverage/snapshots/semantic_babel.snap
@@ -1,8 +1,8 @@
 commit: 6ef16ca4
 
 semantic_babel Summary:
-AST Parsed     : 2221/2221 (100.00%)
-Positive Passed: 2022/2221 (91.04%)
+AST Parsed     : 2225/2225 (100.00%)
+Positive Passed: 2026/2225 (91.06%)
 semantic Error: tasks/coverage/babel/packages/babel-parser/test/fixtures/comments/decorators/decorators-after-export/input.js
 Symbol span mismatch for "C":
 after transform: SymbolId(0): Span { start: 65, end: 66 }
diff --git a/tasks/coverage/snapshots/transformer_babel.snap b/tasks/coverage/snapshots/transformer_babel.snap
index 123a10a0138f7..c8e8ce815d446 100644
--- a/tasks/coverage/snapshots/transformer_babel.snap
+++ b/tasks/coverage/snapshots/transformer_babel.snap
@@ -1,7 +1,7 @@
 commit: 6ef16ca4
 
 transformer_babel Summary:
-AST Parsed     : 2221/2221 (100.00%)
-Positive Passed: 2220/2221 (99.95%)
+AST Parsed     : 2225/2225 (100.00%)
+Positive Passed: 2224/2225 (99.96%)
 Mismatch: tasks/coverage/babel/packages/babel-parser/test/fixtures/core/opts/allowYieldOutsideFunction-true-2/input.js
 
diff --git a/tasks/coverage/snapshots/transformer_misc.snap b/tasks/coverage/snapshots/transformer_misc.snap
index 56ef1c69aa893..7ccc8759d7902 100644
--- a/tasks/coverage/snapshots/transformer_misc.snap
+++ b/tasks/coverage/snapshots/transformer_misc.snap
@@ -1,5 +1,3 @@
 transformer_misc Summary:
 AST Parsed     : 64/64 (100.00%)
-Positive Passed: 63/64 (98.44%)
-Mismatch: tasks/coverage/misc/pass/babel-16776-s.js
-
+Positive Passed: 64/64 (100.00%)
diff --git a/tasks/coverage/snapshots/transformer_typescript.snap b/tasks/coverage/snapshots/transformer_typescript.snap
index 0b389a4f88d3a..2a2d19ec2d02a 100644
--- a/tasks/coverage/snapshots/transformer_typescript.snap
+++ b/tasks/coverage/snapshots/transformer_typescript.snap
@@ -2,8 +2,24 @@ commit: 7f6a8467
 
 transformer_typescript Summary:
 AST Parsed     : 9843/9843 (100.00%)
-Positive Passed: 9841/9843 (99.98%)
+Positive Passed: 9833/9843 (99.90%)
+Mismatch: tasks/coverage/typescript/tests/cases/compiler/jsxEmptyExpressionNotCountedAsChild.tsx
+
+Mismatch: tasks/coverage/typescript/tests/cases/compiler/jsxPartialSpread.tsx
+
+Mismatch: tasks/coverage/typescript/tests/cases/compiler/reactImportUnusedInNewJSXEmit.tsx
+
+Mismatch: tasks/coverage/typescript/tests/cases/compiler/tsxNoTypeAnnotatedSFC.tsx
+
 Mismatch: tasks/coverage/typescript/tests/cases/conformance/classes/propertyMemberDeclarations/autoAccessor2.ts
 
+Mismatch: tasks/coverage/typescript/tests/cases/conformance/declarationEmit/leaveOptionalParameterAsWritten.ts
+
 Mismatch: tasks/coverage/typescript/tests/cases/conformance/esDecorators/classDeclaration/fields/esDecorators-classDeclaration-fields-staticPrivateAccessor.ts
 
+Mismatch: tasks/coverage/typescript/tests/cases/conformance/esDecorators/classExpression/namedEvaluation/esDecorators-classExpression-namedEvaluation.8.ts
+
+Mismatch: tasks/coverage/typescript/tests/cases/conformance/esDecorators/classExpression/namedEvaluation/esDecorators-classExpression-namedEvaluation.9.ts
+
+Mismatch: tasks/coverage/typescript/tests/cases/conformance/jsx/checkJsxGenericTagHasCorrectInferences.tsx
+
diff --git a/tasks/coverage/src/babel/mod.rs b/tasks/coverage/src/babel/mod.rs
index 4ce71643167ed..e9e0ba656f819 100644
--- a/tasks/coverage/src/babel/mod.rs
+++ b/tasks/coverage/src/babel/mod.rs
@@ -51,8 +51,6 @@ impl<T: Case> Suite<T> for BabelSuite<T> {
             "typescript/arrow-function/arrow-like-in-conditional-2",
             // TypeScript allows `satisfies const`, Babel doesn't
             "typescript/cast/satisfies-const-error",
-            // Babel's heuristic for detecting module via unambiguous `await` - not in ES spec, we follow TypeScript
-            "es2022/top-level-await-unambiguous",
             // Escaped `of` binding in using declarations - not worth supporting
             "explicit-resource-management/valid-for-await-using-binding-escaped-of-of",
             "explicit-resource-management/valid-for-using-binding-escaped-of-of",
diff --git a/tasks/coverage/src/driver.rs b/tasks/coverage/src/driver.rs
index d8c8eca184c41..3ea61a4f4967b 100644
--- a/tasks/coverage/src/driver.rs
+++ b/tasks/coverage/src/driver.rs
@@ -38,6 +38,8 @@ pub struct Driver {
     pub panicked: bool,
     pub errors: Vec<OxcDiagnostic>,
     pub printed: String,
+    /// The source type detected after parsing (for unambiguous mode)
+    pub source_type: Option<SourceType>,
 }
 
 impl CompilerInterface for Driver {
@@ -74,6 +76,7 @@ impl CompilerInterface for Driver {
     fn after_parse(&mut self, parser_return: &mut ParserReturn) -> ControlFlow<()> {
         let ParserReturn { program, panicked, errors, .. } = parser_return;
         self.panicked = *panicked;
+        self.source_type = Some(program.source_type);
         self.check_ast_nodes(program);
         if self.check_comments(&program.comments) {
             return ControlFlow::Break(());
diff --git a/tasks/coverage/src/tools/minifier.rs b/tasks/coverage/src/tools/minifier.rs
index c9b00b8bad882..4c4ef1fafae34 100644
--- a/tasks/coverage/src/tools/minifier.rs
+++ b/tasks/coverage/src/tools/minifier.rs
@@ -14,8 +14,19 @@ use crate::{
 
 /// Idempotency test
 fn get_result(source_text: &str, source_type: SourceType) -> TestResult {
-    Driver { compress: Some(CompressOptions::smallest()), codegen: true, ..Driver::default() }
-        .idempotency("Compress", source_text, source_type)
+    let mut driver =
+        Driver { compress: Some(CompressOptions::smallest()), codegen: true, ..Driver::default() };
+    driver.run(source_text, source_type);
+    let printed1 = driver.printed.clone();
+    // Use detected source type from first pass (preserves module/script detection for unambiguous mode)
+    let detected_source_type = driver.source_type.unwrap_or(source_type);
+    driver.run(&printed1, detected_source_type);
+    let printed2 = driver.printed.clone();
+    if printed1 == printed2 {
+        TestResult::Passed
+    } else {
+        TestResult::Mismatch("Compress", printed1, printed2)
+    }
 }
 
 pub struct MinifierTest262Case {
diff --git a/tasks/coverage/src/tools/transformer.rs b/tasks/coverage/src/tools/transformer.rs
index 90090b228c11c..d419a436cfa8d 100644
--- a/tasks/coverage/src/tools/transformer.rs
+++ b/tasks/coverage/src/tools/transformer.rs
@@ -31,11 +31,13 @@ fn get_result(
         driver.run(source_text, source_type);
         driver.printed.clone()
     };
-    // Second pass with only JavaScript syntax
+    // Second pass with detected source type from first pass (preserves module/script detection)
+    let detected_source_type = driver.source_type.unwrap_or(source_type);
     let transformed2 = {
-        driver.run(&transformed1, SourceType::default().with_module(source_type.is_module()));
+        driver.run(&transformed1, detected_source_type);
         driver.printed.clone()
     };
+
     if transformed1 == transformed2 {
         TestResult::Passed
     } else {