diff --git a/src/create-module-declaration.js b/src/create-module-declaration.js
index bb64d4f..81b8682 100644
--- a/src/create-module-declaration.js
+++ b/src/create-module-declaration.js
@@ -279,12 +279,13 @@ export function create_module_declaration(id, entry, created, resolve) {
 						if (identifier && name) {
 							const pos = identifier.getStart(module.ast);
 							const loc = module.locator(pos);
+
 							if (loc) {
-								if (module.source) {
-									// the sourcemaps generated by TypeScript are very inaccurate, borderline useless.
-									// we need to fix them up here. TODO is it only inaccurate in the JSDoc case?
-									const segments = module.source.mappings?.[loc.line - 1];
+								// the sourcemaps generated by TypeScript are very inaccurate, borderline useless.
+								// we need to fix them up here. TODO is it only inaccurate in the JSDoc case?
+								const segments = module.source?.mappings?.[loc.line - 1];
 
+								if (module.source && segments) {
 									// find the segments immediately before and after the generated column
 									const index = segments.findIndex((segment) => segment[0] >= loc.column);
 
diff --git a/test/samples/ignores-missing-sourcemap-segments/input/index.js b/test/samples/ignores-missing-sourcemap-segments/input/index.js
new file mode 100644
index 0000000..ca4fc69
--- /dev/null
+++ b/test/samples/ignores-missing-sourcemap-segments/input/index.js
@@ -0,0 +1,5 @@
+export const object = {
+	answer: 42
+};
+
+export function hello() {}
diff --git a/test/samples/ignores-missing-sourcemap-segments/output/index.d.ts b/test/samples/ignores-missing-sourcemap-segments/output/index.d.ts
new file mode 100644
index 0000000..cf27525
--- /dev/null
+++ b/test/samples/ignores-missing-sourcemap-segments/output/index.d.ts
@@ -0,0 +1,8 @@
+declare module 'ignores-missing-sourcemap-segments' {
+	export function hello(): void;
+	export namespace object {
+		const answer: number;
+	}
+}
+
+//# sourceMappingURL=index.d.ts.map
diff --git a/test/samples/ignores-missing-sourcemap-segments/output/index.d.ts.map b/test/samples/ignores-missing-sourcemap-segments/output/index.d.ts.map
new file mode 100644
index 0000000..e1bbe17
--- /dev/null
+++ b/test/samples/ignores-missing-sourcemap-segments/output/index.d.ts.map
@@ -0,0 +1,17 @@
+{
+	"version": 3,
+	"file": "index.d.ts",
+	"names": [
+		"hello",
+		"object"
+	],
+	"sources": [
+		"../input/index.js",
+		"../input/index.d.ts"
+	],
+	"sourcesContent": [
+		null,
+		null
+	],
+	"mappings": ";iBAIgBA,KAAKA;kBCHJC,MAAMA"
+}
\ No newline at end of file