diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 1b0904723df..1e1f9b27967 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -21773,9 +21773,14 @@ namespace ts {
                 return getTypeOfParameter(signature.parameters[pos]);
             }
             if (signature.hasRestParameter) {
+                // We want to return the value undefined for an out of bounds parameter position,
+                // so we need to check bounds here before calling getIndexedAccessType (which
+                // otherwise would return the type 'undefined').
                 const restType = getTypeOfSymbol(signature.parameters[paramCount]);
-                const indexType = getLiteralType(pos - paramCount);
-                return getIndexedAccessType(restType, indexType);
+                const index = pos - paramCount;
+                if (!isTupleType(restType) || restType.target.hasRestElement || index < (restType.typeArguments || emptyArray).length) {
+                    return getIndexedAccessType(restType, getLiteralType(index));
+                }
             }
             return undefined;
         }
diff --git a/tests/baselines/reference/getParameterNameAtPosition.errors.txt b/tests/baselines/reference/getParameterNameAtPosition.errors.txt
deleted file mode 100644
index 74a31fd3def..00000000000
--- a/tests/baselines/reference/getParameterNameAtPosition.errors.txt
+++ /dev/null
@@ -1,20 +0,0 @@
-tests/cases/compiler/getParameterNameAtPosition.ts(9,7): error TS2345: Argument of type 'Mock<[any]>' is not assignable to parameter of type 'Tester'.
-  Types of parameters 'args_1' and 'done' are incompatible.
-    Type '(...args: any[]) => any' is not assignable to type 'undefined'.
-
-
-==== tests/cases/compiler/getParameterNameAtPosition.ts (1 errors) ====
-    // Repro from #30171
-    
-    interface Mock<Y extends any[]> extends Function {
-        (...args: Y): any;
-    }
-    type Tester = (opts: any, done: (...args: any[]) => any) => any;
-    declare function cases(tester: Tester): void;
-    declare function fn<Y extends any[]>(implementation?: (...args: Y) => any): Mock<Y>;
-    cases(fn(opts => { }));
-          ~~~~~~~~~~~~~~~
-!!! error TS2345: Argument of type 'Mock<[any]>' is not assignable to parameter of type 'Tester'.
-!!! error TS2345:   Types of parameters 'args_1' and 'done' are incompatible.
-!!! error TS2345:     Type '(...args: any[]) => any' is not assignable to type 'undefined'.
-    
\ No newline at end of file