diff --git a/tests/baselines/reference/dontWiden.js b/tests/baselines/reference/dontWiden.js
index d4581913d1443..f9a19b5ab7320 100644
--- a/tests/baselines/reference/dontWiden.js
+++ b/tests/baselines/reference/dontWiden.js
@@ -4,6 +4,7 @@ const d = { a: 1, b: 'c' };
 
 interface SomeInterface { a: boolean }
 declare function foo<T extends any[]>(arg: T): { hi: T };
+declare function boo<T extends number[]>(arg: T): { hi: T };
 declare function bar(arg: SomeInterface): void
 declare function baz(arg: [number, 2, 3 | number]): void
 declare function bag(arg: number[]): void
@@ -19,6 +20,8 @@ bar({a: true});
 baz([1, 2, 3]);
 bag([1, 2, 3]);
 bag(e);
+boo([1, 2, 3]);
+boo(e);
 
 
 //// [dontWiden.js]
@@ -34,3 +37,5 @@ bar({ a: true });
 baz([1, 2, 3]);
 bag([1, 2, 3]);
 bag(e);
+boo([1, 2, 3]);
+boo(e);
diff --git a/tests/baselines/reference/dontWiden.symbols b/tests/baselines/reference/dontWiden.symbols
index ede7b6f989540..a38508e9696f4 100644
--- a/tests/baselines/reference/dontWiden.symbols
+++ b/tests/baselines/reference/dontWiden.symbols
@@ -19,46 +19,61 @@ declare function foo<T extends any[]>(arg: T): { hi: T };
 >hi : Symbol(hi, Decl(dontWiden.ts, 4, 48))
 >T : Symbol(T, Decl(dontWiden.ts, 4, 21))
 
+declare function boo<T extends number[]>(arg: T): { hi: T };
+>boo : Symbol(boo, Decl(dontWiden.ts, 4, 57))
+>T : Symbol(T, Decl(dontWiden.ts, 5, 21))
+>arg : Symbol(arg, Decl(dontWiden.ts, 5, 41))
+>T : Symbol(T, Decl(dontWiden.ts, 5, 21))
+>hi : Symbol(hi, Decl(dontWiden.ts, 5, 51))
+>T : Symbol(T, Decl(dontWiden.ts, 5, 21))
+
 declare function bar(arg: SomeInterface): void
->bar : Symbol(bar, Decl(dontWiden.ts, 4, 57))
->arg : Symbol(arg, Decl(dontWiden.ts, 5, 21))
+>bar : Symbol(bar, Decl(dontWiden.ts, 5, 60))
+>arg : Symbol(arg, Decl(dontWiden.ts, 6, 21))
 >SomeInterface : Symbol(SomeInterface, Decl(dontWiden.ts, 1, 27))
 
 declare function baz(arg: [number, 2, 3 | number]): void
->baz : Symbol(baz, Decl(dontWiden.ts, 5, 46))
->arg : Symbol(arg, Decl(dontWiden.ts, 6, 21))
+>baz : Symbol(baz, Decl(dontWiden.ts, 6, 46))
+>arg : Symbol(arg, Decl(dontWiden.ts, 7, 21))
 
 declare function bag(arg: number[]): void
->bag : Symbol(bag, Decl(dontWiden.ts, 6, 56))
->arg : Symbol(arg, Decl(dontWiden.ts, 7, 21))
+>bag : Symbol(bag, Decl(dontWiden.ts, 7, 56))
+>arg : Symbol(arg, Decl(dontWiden.ts, 8, 21))
 
 // As variable assignees
 const a: number[] = [1, 2, 3];
->a : Symbol(a, Decl(dontWiden.ts, 10, 5))
+>a : Symbol(a, Decl(dontWiden.ts, 11, 5))
 
 const b: SomeInterface = {a: true};
->b : Symbol(b, Decl(dontWiden.ts, 11, 5))
+>b : Symbol(b, Decl(dontWiden.ts, 12, 5))
 >SomeInterface : Symbol(SomeInterface, Decl(dontWiden.ts, 1, 27))
->a : Symbol(a, Decl(dontWiden.ts, 11, 26))
+>a : Symbol(a, Decl(dontWiden.ts, 12, 26))
 
 const e = [1, 2, 3];
->e : Symbol(e, Decl(dontWiden.ts, 12, 5))
+>e : Symbol(e, Decl(dontWiden.ts, 13, 5))
 
 // Same, but as arguments
 foo([1, 2, 3]);
 >foo : Symbol(foo, Decl(dontWiden.ts, 3, 38))
 
 bar({a: true});
->bar : Symbol(bar, Decl(dontWiden.ts, 4, 57))
->a : Symbol(a, Decl(dontWiden.ts, 16, 5))
+>bar : Symbol(bar, Decl(dontWiden.ts, 5, 60))
+>a : Symbol(a, Decl(dontWiden.ts, 17, 5))
 
 baz([1, 2, 3]);
->baz : Symbol(baz, Decl(dontWiden.ts, 5, 46))
+>baz : Symbol(baz, Decl(dontWiden.ts, 6, 46))
 
 bag([1, 2, 3]);
->bag : Symbol(bag, Decl(dontWiden.ts, 6, 56))
+>bag : Symbol(bag, Decl(dontWiden.ts, 7, 56))
 
 bag(e);
->bag : Symbol(bag, Decl(dontWiden.ts, 6, 56))
->e : Symbol(e, Decl(dontWiden.ts, 12, 5))
+>bag : Symbol(bag, Decl(dontWiden.ts, 7, 56))
+>e : Symbol(e, Decl(dontWiden.ts, 13, 5))
+
+boo([1, 2, 3]);
+>boo : Symbol(boo, Decl(dontWiden.ts, 4, 57))
+
+boo(e);
+>boo : Symbol(boo, Decl(dontWiden.ts, 4, 57))
+>e : Symbol(e, Decl(dontWiden.ts, 13, 5))
 
diff --git a/tests/baselines/reference/dontWiden.types b/tests/baselines/reference/dontWiden.types
index 5c222cf71ed9f..40ffa6344b583 100644
--- a/tests/baselines/reference/dontWiden.types
+++ b/tests/baselines/reference/dontWiden.types
@@ -25,6 +25,14 @@ declare function foo<T extends any[]>(arg: T): { hi: T };
 >hi : T
 >T : T
 
+declare function boo<T extends number[]>(arg: T): { hi: T };
+>boo : <T extends number[]>(arg: T) => { hi: T; }
+>T : T
+>arg : T
+>T : T
+>hi : T
+>T : T
+
 declare function bar(arg: SomeInterface): void
 >bar : (arg: SomeInterface) => void
 >arg : SomeInterface
@@ -97,3 +105,16 @@ bag(e);
 >bag : (arg: number[]) => void
 >e : [1, 2, 3]
 
+boo([1, 2, 3]);
+>boo([1, 2, 3]) : { hi: [1, 2, 3]; }
+>boo : <T extends number[]>(arg: T) => { hi: T; }
+>[1, 2, 3] : [1, 2, 3]
+>1 : 1
+>2 : 2
+>3 : 3
+
+boo(e);
+>boo(e) : { hi: [1, 2, 3]; }
+>boo : <T extends number[]>(arg: T) => { hi: T; }
+>e : [1, 2, 3]
+
diff --git a/tests/cases/compiler/dontWiden.ts b/tests/cases/compiler/dontWiden.ts
index 26b1719b6a791..fb437c733a072 100644
--- a/tests/cases/compiler/dontWiden.ts
+++ b/tests/cases/compiler/dontWiden.ts
@@ -5,6 +5,7 @@ const d = { a: 1, b: 'c' };
 
 interface SomeInterface { a: boolean }
 declare function foo<T extends any[]>(arg: T): { hi: T };
+declare function boo<T extends number[]>(arg: T): { hi: T };
 declare function bar(arg: SomeInterface): void
 declare function baz(arg: [number, 2, 3 | number]): void
 declare function bag(arg: number[]): void
@@ -20,3 +21,5 @@ bar({a: true});
 baz([1, 2, 3]);
 bag([1, 2, 3]);
 bag(e);
+boo([1, 2, 3]);
+boo(e);