diff --git a/tests/baselines/reference/ambientDeclarationsPatterns_merging2.errors.txt b/tests/baselines/reference/ambientDeclarationsPatterns_merging2.errors.txt
new file mode 100644
index 00000000000..67c44a528b5
--- /dev/null
+++ b/tests/baselines/reference/ambientDeclarationsPatterns_merging2.errors.txt
@@ -0,0 +1,25 @@
+tests/cases/conformance/ambient/testB.ts(1,22): error TS2305: Module '"*.foo"' has no exported member 'onlyInA'.
+tests/cases/conformance/ambient/testB.ts(1,31): error TS2305: Module '"*.foo"' has no exported member 'alsoOnlyInA'.
+
+
+==== tests/cases/conformance/ambient/types.ts (0 errors) ====
+    declare module "*.foo" {
+      let everywhere: string;
+    }
+    
+    
+==== tests/cases/conformance/ambient/testA.ts (0 errors) ====
+    import { everywhere, onlyInA, alsoOnlyInA } from "a.foo";
+    declare module "a.foo" {
+      let onlyInA: number;
+    }
+    
+==== tests/cases/conformance/ambient/testB.ts (2 errors) ====
+    import { everywhere, onlyInA, alsoOnlyInA } from "b.foo"; // Error
+                         ~~~~~~~
+!!! error TS2305: Module '"*.foo"' has no exported member 'onlyInA'.
+                                  ~~~~~~~~~~~
+!!! error TS2305: Module '"*.foo"' has no exported member 'alsoOnlyInA'.
+    declare module "a.foo" {
+      let alsoOnlyInA: number;
+    }
\ No newline at end of file
diff --git a/tests/baselines/reference/ambientDeclarationsPatterns_merging2.js b/tests/baselines/reference/ambientDeclarationsPatterns_merging2.js
new file mode 100644
index 00000000000..65726bba722
--- /dev/null
+++ b/tests/baselines/reference/ambientDeclarationsPatterns_merging2.js
@@ -0,0 +1,27 @@
+//// [tests/cases/conformance/ambient/ambientDeclarationsPatterns_merging2.ts] ////
+
+//// [types.ts]
+declare module "*.foo" {
+  let everywhere: string;
+}
+
+
+//// [testA.ts]
+import { everywhere, onlyInA, alsoOnlyInA } from "a.foo";
+declare module "a.foo" {
+  let onlyInA: number;
+}
+
+//// [testB.ts]
+import { everywhere, onlyInA, alsoOnlyInA } from "b.foo"; // Error
+declare module "a.foo" {
+  let alsoOnlyInA: number;
+}
+
+//// [types.js]
+//// [testA.js]
+"use strict";
+exports.__esModule = true;
+//// [testB.js]
+"use strict";
+exports.__esModule = true;
diff --git a/tests/baselines/reference/ambientDeclarationsPatterns_merging2.symbols b/tests/baselines/reference/ambientDeclarationsPatterns_merging2.symbols
new file mode 100644
index 00000000000..447cd999c98
--- /dev/null
+++ b/tests/baselines/reference/ambientDeclarationsPatterns_merging2.symbols
@@ -0,0 +1,34 @@
+=== tests/cases/conformance/ambient/types.ts ===
+declare module "*.foo" {
+>"*.foo" : Symbol("*.foo", Decl(types.ts, 0, 0))
+
+  let everywhere: string;
+>everywhere : Symbol(everywhere, Decl(types.ts, 1, 5))
+}
+
+
+=== tests/cases/conformance/ambient/testA.ts ===
+import { everywhere, onlyInA, alsoOnlyInA } from "a.foo";
+>everywhere : Symbol(everywhere, Decl(testA.ts, 0, 8))
+>onlyInA : Symbol(onlyInA, Decl(testA.ts, 0, 20))
+>alsoOnlyInA : Symbol(alsoOnlyInA, Decl(testA.ts, 0, 29))
+
+declare module "a.foo" {
+>"a.foo" : Symbol("a.foo", Decl(testA.ts, 0, 57), Decl(types.ts, 0, 0), Decl(testB.ts, 0, 57))
+
+  let onlyInA: number;
+>onlyInA : Symbol(onlyInA, Decl(testA.ts, 2, 5))
+}
+
+=== tests/cases/conformance/ambient/testB.ts ===
+import { everywhere, onlyInA, alsoOnlyInA } from "b.foo"; // Error
+>everywhere : Symbol(everywhere, Decl(testB.ts, 0, 8))
+>onlyInA : Symbol(onlyInA, Decl(testB.ts, 0, 20))
+>alsoOnlyInA : Symbol(alsoOnlyInA, Decl(testB.ts, 0, 29))
+
+declare module "a.foo" {
+>"a.foo" : Symbol("a.foo", Decl(testA.ts, 0, 57), Decl(types.ts, 0, 0), Decl(testB.ts, 0, 57))
+
+  let alsoOnlyInA: number;
+>alsoOnlyInA : Symbol(alsoOnlyInA, Decl(testB.ts, 2, 5))
+}
diff --git a/tests/baselines/reference/ambientDeclarationsPatterns_merging2.types b/tests/baselines/reference/ambientDeclarationsPatterns_merging2.types
new file mode 100644
index 00000000000..b4f0d50db19
--- /dev/null
+++ b/tests/baselines/reference/ambientDeclarationsPatterns_merging2.types
@@ -0,0 +1,34 @@
+=== tests/cases/conformance/ambient/types.ts ===
+declare module "*.foo" {
+>"*.foo" : typeof import("*.foo")
+
+  let everywhere: string;
+>everywhere : string
+}
+
+
+=== tests/cases/conformance/ambient/testA.ts ===
+import { everywhere, onlyInA, alsoOnlyInA } from "a.foo";
+>everywhere : string
+>onlyInA : number
+>alsoOnlyInA : number
+
+declare module "a.foo" {
+>"a.foo" : typeof import("a.foo")
+
+  let onlyInA: number;
+>onlyInA : number
+}
+
+=== tests/cases/conformance/ambient/testB.ts ===
+import { everywhere, onlyInA, alsoOnlyInA } from "b.foo"; // Error
+>everywhere : string
+>onlyInA : any
+>alsoOnlyInA : any
+
+declare module "a.foo" {
+>"a.foo" : typeof import("a.foo")
+
+  let alsoOnlyInA: number;
+>alsoOnlyInA : number
+}
diff --git a/tests/cases/conformance/ambient/ambientDeclarationsPatterns_merging2.ts b/tests/cases/conformance/ambient/ambientDeclarationsPatterns_merging2.ts
new file mode 100644
index 00000000000..7b02846c242
--- /dev/null
+++ b/tests/cases/conformance/ambient/ambientDeclarationsPatterns_merging2.ts
@@ -0,0 +1,17 @@
+// @filename: types.ts
+declare module "*.foo" {
+  let everywhere: string;
+}
+
+
+// @filename: testA.ts
+import { everywhere, onlyInA, alsoOnlyInA } from "a.foo";
+declare module "a.foo" {
+  let onlyInA: number;
+}
+
+// @filename: testB.ts
+import { everywhere, onlyInA, alsoOnlyInA } from "b.foo"; // Error
+declare module "a.foo" {
+  let alsoOnlyInA: number;
+}
\ No newline at end of file