diff --git a/internal/parser/parser.go b/internal/parser/parser.go
index 4f2ea48ffb..8ced9412b8 100644
--- a/internal/parser/parser.go
+++ b/internal/parser/parser.go
@@ -261,6 +261,7 @@ type ParserState struct {
 	scannerState                scanner.ScannerState
 	contextFlags                ast.NodeFlags
 	diagnosticsLen              int
+	jsDiagnosticsLen            int
 	statementHasAwaitIdentifier bool
 	hasParseError               bool
 }
@@ -270,6 +271,7 @@ func (p *Parser) mark() ParserState {
 		scannerState:                p.scanner.Mark(),
 		contextFlags:                p.contextFlags,
 		diagnosticsLen:              len(p.diagnostics),
+		jsDiagnosticsLen:            len(p.jsDiagnostics),
 		statementHasAwaitIdentifier: p.statementHasAwaitIdentifier,
 		hasParseError:               p.hasParseError,
 	}
@@ -280,6 +282,7 @@ func (p *Parser) rewind(state ParserState) {
 	p.token = p.scanner.Token()
 	p.contextFlags = state.contextFlags
 	p.diagnostics = p.diagnostics[0:state.diagnosticsLen]
+	p.jsDiagnostics = p.jsDiagnostics[0:state.jsDiagnosticsLen]
 	p.statementHasAwaitIdentifier = state.statementHasAwaitIdentifier
 	p.hasParseError = state.hasParseError
 }
diff --git a/testdata/baselines/reference/compiler/jsSpeculativeParsingError.symbols b/testdata/baselines/reference/compiler/jsSpeculativeParsingError.symbols
new file mode 100644
index 0000000000..f5840192c2
--- /dev/null
+++ b/testdata/baselines/reference/compiler/jsSpeculativeParsingError.symbols
@@ -0,0 +1,18 @@
+//// [tests/cases/compiler/jsSpeculativeParsingError.ts] ////
+
+=== t.js ===
+const is_morning = new Date().getHours() < 12;
+>is_morning : Symbol(is_morning, Decl(t.js, 0, 5))
+>new Date().getHours : Symbol(Date.getHours, Decl(lib.es5.d.ts, --, --))
+>Date : Symbol(Date, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --), Decl(lib.scripthost.d.ts, --, --))
+>getHours : Symbol(Date.getHours, Decl(lib.es5.d.ts, --, --))
+
+// prettier-ignore
+const greeting = ([
+>greeting : Symbol(greeting, Decl(t.js, 3, 5))
+
+  is_morning ? 'good morning' : 'good evening'
+>is_morning : Symbol(is_morning, Decl(t.js, 0, 5))
+
+]);
+
diff --git a/testdata/baselines/reference/compiler/jsSpeculativeParsingError.types b/testdata/baselines/reference/compiler/jsSpeculativeParsingError.types
new file mode 100644
index 0000000000..cae4c55f58
--- /dev/null
+++ b/testdata/baselines/reference/compiler/jsSpeculativeParsingError.types
@@ -0,0 +1,27 @@
+//// [tests/cases/compiler/jsSpeculativeParsingError.ts] ////
+
+=== t.js ===
+const is_morning = new Date().getHours() < 12;
+>is_morning : boolean
+>new Date().getHours() < 12 : boolean
+>new Date().getHours() : number
+>new Date().getHours : () => number
+>new Date() : Date
+>Date : DateConstructor
+>getHours : () => number
+>12 : 12
+
+// prettier-ignore
+const greeting = ([
+>greeting : string[]
+>([  is_morning ? 'good morning' : 'good evening']) : string[]
+>[  is_morning ? 'good morning' : 'good evening'] : string[]
+
+  is_morning ? 'good morning' : 'good evening'
+>is_morning ? 'good morning' : 'good evening' : "good evening" | "good morning"
+>is_morning : boolean
+>'good morning' : "good morning"
+>'good evening' : "good evening"
+
+]);
+
diff --git a/testdata/tests/cases/compiler/jsSpeculativeParsingError.ts b/testdata/tests/cases/compiler/jsSpeculativeParsingError.ts
new file mode 100644
index 0000000000..3fd91571fd
--- /dev/null
+++ b/testdata/tests/cases/compiler/jsSpeculativeParsingError.ts
@@ -0,0 +1,12 @@
+// @strict: true
+// @allowJs: true
+// @checkJs: true
+// @noEmit: true
+// @filename: t.js
+
+const is_morning = new Date().getHours() < 12;
+
+// prettier-ignore
+const greeting = ([
+  is_morning ? 'good morning' : 'good evening'
+]);