diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index b1d39a4c09161..5da6244b552cb 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -4840,15 +4840,60 @@ namespace ts {
             }
         }
 
-        function getDefaultOfTypeParameter(typeParameter: TypeParameter): Type {
+        /**
+         * Gets the default type for a type parameter.
+         *
+         * If the type parameter is the result of an instantiation, this gets the instantiated
+         * default type of its target. If the type parameter has no default type, `undefined`
+         * is returned.
+         *
+         * This function *does not* perform a circularity check.
+         */
+        function getDefaultFromTypeParameter(typeParameter: TypeParameter): Type | undefined {
+            if (!typeParameter.default) {
+                if (typeParameter.target) {
+                    const targetDefault = getDefaultFromTypeParameter(typeParameter.target);
+                    typeParameter.default = targetDefault ? instantiateType(targetDefault, typeParameter.mapper) : noConstraintOrDefaultType;
+                }
+                else {
+                    const defaultDeclaration = typeParameter.symbol && forEach(typeParameter.symbol.declarations, decl => isTypeParameter(decl) && decl.default);
+                    typeParameter.default = defaultDeclaration ? getTypeFromTypeNode(defaultDeclaration) : noConstraintOrDefaultType;
+                }
+            }
+            return typeParameter.default === noConstraintOrDefaultType ? undefined : typeParameter.default;
+        }
+
+        /**
+         * Gets the default type for a type parameter.
+         *
+         * If the type parameter is the result of an instantiation, this gets the instantiated
+         * default type of its target. If the type parameter has no default type, or if the default
+         * type circularly references the type parameter, `undefined` is returned.
+         *
+         * This function *does* perform a circularity check.
+         */
+        function getDefaultOfTypeParameter(typeParameter: TypeParameter): Type | undefined {
             return hasNonCircularDefault(typeParameter) ? getDefaultFromTypeParameter(typeParameter) : undefined;
         }
 
-        function hasNonCircularDefault(type: TypeParameter) {
-            return getResolvedDefault(type) !== circularConstraintOrDefaultType;
+        /**
+         * Determines whether a type parameter has a non-circular default type.
+         *
+         * Note that this function also returns `true` if a type parameter *does not* have a
+         * default type.
+         */
+        function hasNonCircularDefault(typeParameter: TypeParameter): boolean {
+            return getResolvedDefault(typeParameter) !== circularConstraintOrDefaultType;
         }
 
-        function getResolvedDefault(typeParameter: TypeParameter) {
+        /**
+         * Resolves the default type of a type parameter.
+         *
+         * If the type parameter has no default, the `noConstraintOrDefaultType` singleton is
+         * returned. If the type parameter has a circular default, the
+         * `circularConstraintOrDefaultType` singleton is returned.
+         */
+        function getResolvedDefault(typeParameter: TypeParameter): Type {
             if (!typeParameter.resolvedDefault) {
                 if (!pushTypeResolution(typeParameter, TypeSystemPropertyName.ResolvedDefault)) {
                     return circularConstraintOrDefaultType;
@@ -4863,6 +4908,12 @@ namespace ts {
             return typeParameter.resolvedDefault;
         }
 
+        /**
+         * Recursively resolves the default type for a type.
+         *
+         * If the type is a union or intersection type and any of its constituents is a circular
+         * reference, the `circularConstraintOrDefaultType` singleton is returned.
+         */
         function getResolvedDefaultWorker(type: Type): Type {
             if (type.flags & TypeFlags.TypeParameter) {
                 return getResolvedDefault(<TypeParameter>type);
@@ -5173,6 +5224,14 @@ namespace ts {
             return minTypeArgumentCount;
         }
 
+        /**
+         * Fill in default types for unsupplied type arguments. If `typeArguments` is undefined
+         * when a default type is supplied, a new array will be created and returned.
+         *
+         * @param typeArguments The supplied type arguments.
+         * @param typeParameters The requested type parameters.
+         * @param minTypeArgumentCount The minimum number of required type arguments.
+         */
         function fillMissingTypeArguments(typeArguments: Type[] | undefined, typeParameters: TypeParameter[] | undefined, minTypeArgumentCount: number) {
             const numTypeParameters = typeParameters ? typeParameters.length : 0;
             if (numTypeParameters) {
@@ -5488,20 +5547,6 @@ namespace ts {
             return typeParameter.constraint === noConstraintOrDefaultType ? undefined : typeParameter.constraint;
         }
 
-        function getDefaultFromTypeParameter(typeParameter: TypeParameter): Type | undefined {
-            if (!typeParameter.default) {
-                if (typeParameter.target) {
-                    const targetDefault = getDefaultFromTypeParameter(typeParameter.target);
-                    typeParameter.default = targetDefault ? instantiateType(targetDefault, typeParameter.mapper) : noConstraintOrDefaultType;
-                }
-                else {
-                    const defaultDeclaration = typeParameter.symbol && forEach(typeParameter.symbol.declarations, decl => isTypeParameter(decl) && decl.default);
-                    typeParameter.default = defaultDeclaration ? getTypeFromTypeNode(defaultDeclaration) : noConstraintOrDefaultType;
-                }
-            }
-            return typeParameter.default === noConstraintOrDefaultType ? undefined : typeParameter.default;
-        }
-
         function getParentSymbolOfTypeParameter(typeParameter: TypeParameter): Symbol {
             return getSymbolOfNode(getDeclarationOfKind(typeParameter.symbol, SyntaxKind.TypeParameter).parent);
         }
@@ -13535,6 +13580,7 @@ namespace ts {
                         ? createInferenceContext(originalCandidate, /*inferUnionTypes*/ false)
                         : undefined;
 
+                    // fix each supplied type argument in the inference context
                     if (typeArguments) {
                         for (let i = 0; i < typeArguments.length; i++) {
                             inferenceContext.inferredTypes[i] = getTypeFromTypeNode(typeArguments[i]);
@@ -13545,8 +13591,10 @@ namespace ts {
                     while (true) {
                         candidate = originalCandidate;
                         if (candidate.typeParameters) {
-                            typeArgumentsAreValid = typeArguments ? checkTypeArguments(candidate, typeArguments, inferenceContext.inferredTypes, /*reportErrors*/ false) : true;
+                            // Check any supplied type arguments against the candidate.
+                            typeArgumentsAreValid = !typeArguments || checkTypeArguments(candidate, typeArguments, inferenceContext.inferredTypes, /*reportErrors*/ false);
                             if (typeArgumentsAreValid) {
+                                // Infer any unsupplied type arguments for the candidate.
                                 inferTypeArguments(node, candidate, args, excludeArgument, inferenceContext);
                                 typeArgumentsAreValid = inferenceContext.failedTypeParameterIndex === undefined;
                             }
diff --git a/tests/baselines/reference/genericDefaults.js b/tests/baselines/reference/genericDefaults.js
index aeedbd5d9e162..c61a42c965101 100644
--- a/tests/baselines/reference/genericDefaults.js
+++ b/tests/baselines/reference/genericDefaults.js
@@ -42,6 +42,28 @@ const f03c06 = f03<number, number>();
 const f03c07 = f03<number, number>(1);
 const f03c08 = f03<number, number>(1, 2);
 
+declare function f04<T, U = T | { a: number }>(a?: T, b?: U): [T, U];
+const f04c00 = f04();
+const f04c01 = f04(1);
+const f04c02 = f04(1, 1);
+const f04c03 = f04<number>();
+const f04c04 = f04<number>(1);
+const f04c05 = f04<number>(1, 2);
+const f04c06 = f04<number, number>();
+const f04c07 = f04<number, number>(1);
+const f04c08 = f04<number, number>(1, 2);
+
+declare function f05<T, U = T & { a: number }>(a?: T, b?: U): [T, U];
+const f05c00 = f05();
+const f05c01 = f05(1);
+const f05c02 = f05(1, 1);
+const f05c03 = f05<number>();
+const f05c04 = f05<number>(1);
+const f05c05 = f05<number>(1, 2);
+const f05c06 = f05<number, number>();
+const f05c07 = f05<number, number>(1);
+const f05c08 = f05<number, number>(1, 2);
+
 interface i00<T = number> { a: T; }
 const i00c00 = (<i00>x).a;
 const i00c01 = (<i00<number>>x).a;
@@ -120,6 +142,24 @@ var f03c05 = f03(1, 2);
 var f03c06 = f03();
 var f03c07 = f03(1);
 var f03c08 = f03(1, 2);
+var f04c00 = f04();
+var f04c01 = f04(1);
+var f04c02 = f04(1, 1);
+var f04c03 = f04();
+var f04c04 = f04(1);
+var f04c05 = f04(1, 2);
+var f04c06 = f04();
+var f04c07 = f04(1);
+var f04c08 = f04(1, 2);
+var f05c00 = f05();
+var f05c01 = f05(1);
+var f05c02 = f05(1, 1);
+var f05c03 = f05();
+var f05c04 = f05(1);
+var f05c05 = f05(1, 2);
+var f05c06 = f05();
+var f05c07 = f05(1);
+var f05c08 = f05(1, 2);
 var i00c00 = x.a;
 var i00c01 = x.a;
 var i01c00 = x.a;
@@ -187,6 +227,46 @@ declare const f03c05: [number, number];
 declare const f03c06: [number, number];
 declare const f03c07: [number, number];
 declare const f03c08: [number, number];
+declare function f04<T, U = T | {
+    a: number;
+}>(a?: T, b?: U): [T, U];
+declare const f04c00: [{}, {} | {
+    a: number;
+}];
+declare const f04c01: [number, number | {
+    a: number;
+}];
+declare const f04c02: [number, number];
+declare const f04c03: [number, number | {
+    a: number;
+}];
+declare const f04c04: [number, number | {
+    a: number;
+}];
+declare const f04c05: [number, number];
+declare const f04c06: [number, number];
+declare const f04c07: [number, number];
+declare const f04c08: [number, number];
+declare function f05<T, U = T & {
+    a: number;
+}>(a?: T, b?: U): [T, U];
+declare const f05c00: [{}, {} & {
+    a: number;
+}];
+declare const f05c01: [number, number & {
+    a: number;
+}];
+declare const f05c02: [number, number];
+declare const f05c03: [number, number & {
+    a: number;
+}];
+declare const f05c04: [number, number & {
+    a: number;
+}];
+declare const f05c05: [number, number];
+declare const f05c06: [number, number];
+declare const f05c07: [number, number];
+declare const f05c08: [number, number];
 interface i00<T = number> {
     a: T;
 }
diff --git a/tests/baselines/reference/genericDefaults.symbols b/tests/baselines/reference/genericDefaults.symbols
index fe8dff0412ee6..a43b6fa9f4363 100644
--- a/tests/baselines/reference/genericDefaults.symbols
+++ b/tests/baselines/reference/genericDefaults.symbols
@@ -178,213 +178,311 @@ const f03c08 = f03<number, number>(1, 2);
 >f03c08 : Symbol(f03c08, Decl(genericDefaults.ts, 41, 5))
 >f03 : Symbol(f03, Decl(genericDefaults.ts, 30, 43))
 
+declare function f04<T, U = T | { a: number }>(a?: T, b?: U): [T, U];
+>f04 : Symbol(f04, Decl(genericDefaults.ts, 41, 41))
+>T : Symbol(T, Decl(genericDefaults.ts, 43, 21))
+>U : Symbol(U, Decl(genericDefaults.ts, 43, 23))
+>T : Symbol(T, Decl(genericDefaults.ts, 43, 21))
+>a : Symbol(a, Decl(genericDefaults.ts, 43, 33))
+>a : Symbol(a, Decl(genericDefaults.ts, 43, 47))
+>T : Symbol(T, Decl(genericDefaults.ts, 43, 21))
+>b : Symbol(b, Decl(genericDefaults.ts, 43, 53))
+>U : Symbol(U, Decl(genericDefaults.ts, 43, 23))
+>T : Symbol(T, Decl(genericDefaults.ts, 43, 21))
+>U : Symbol(U, Decl(genericDefaults.ts, 43, 23))
+
+const f04c00 = f04();
+>f04c00 : Symbol(f04c00, Decl(genericDefaults.ts, 44, 5))
+>f04 : Symbol(f04, Decl(genericDefaults.ts, 41, 41))
+
+const f04c01 = f04(1);
+>f04c01 : Symbol(f04c01, Decl(genericDefaults.ts, 45, 5))
+>f04 : Symbol(f04, Decl(genericDefaults.ts, 41, 41))
+
+const f04c02 = f04(1, 1);
+>f04c02 : Symbol(f04c02, Decl(genericDefaults.ts, 46, 5))
+>f04 : Symbol(f04, Decl(genericDefaults.ts, 41, 41))
+
+const f04c03 = f04<number>();
+>f04c03 : Symbol(f04c03, Decl(genericDefaults.ts, 47, 5))
+>f04 : Symbol(f04, Decl(genericDefaults.ts, 41, 41))
+
+const f04c04 = f04<number>(1);
+>f04c04 : Symbol(f04c04, Decl(genericDefaults.ts, 48, 5))
+>f04 : Symbol(f04, Decl(genericDefaults.ts, 41, 41))
+
+const f04c05 = f04<number>(1, 2);
+>f04c05 : Symbol(f04c05, Decl(genericDefaults.ts, 49, 5))
+>f04 : Symbol(f04, Decl(genericDefaults.ts, 41, 41))
+
+const f04c06 = f04<number, number>();
+>f04c06 : Symbol(f04c06, Decl(genericDefaults.ts, 50, 5))
+>f04 : Symbol(f04, Decl(genericDefaults.ts, 41, 41))
+
+const f04c07 = f04<number, number>(1);
+>f04c07 : Symbol(f04c07, Decl(genericDefaults.ts, 51, 5))
+>f04 : Symbol(f04, Decl(genericDefaults.ts, 41, 41))
+
+const f04c08 = f04<number, number>(1, 2);
+>f04c08 : Symbol(f04c08, Decl(genericDefaults.ts, 52, 5))
+>f04 : Symbol(f04, Decl(genericDefaults.ts, 41, 41))
+
+declare function f05<T, U = T & { a: number }>(a?: T, b?: U): [T, U];
+>f05 : Symbol(f05, Decl(genericDefaults.ts, 52, 41))
+>T : Symbol(T, Decl(genericDefaults.ts, 54, 21))
+>U : Symbol(U, Decl(genericDefaults.ts, 54, 23))
+>T : Symbol(T, Decl(genericDefaults.ts, 54, 21))
+>a : Symbol(a, Decl(genericDefaults.ts, 54, 33))
+>a : Symbol(a, Decl(genericDefaults.ts, 54, 47))
+>T : Symbol(T, Decl(genericDefaults.ts, 54, 21))
+>b : Symbol(b, Decl(genericDefaults.ts, 54, 53))
+>U : Symbol(U, Decl(genericDefaults.ts, 54, 23))
+>T : Symbol(T, Decl(genericDefaults.ts, 54, 21))
+>U : Symbol(U, Decl(genericDefaults.ts, 54, 23))
+
+const f05c00 = f05();
+>f05c00 : Symbol(f05c00, Decl(genericDefaults.ts, 55, 5))
+>f05 : Symbol(f05, Decl(genericDefaults.ts, 52, 41))
+
+const f05c01 = f05(1);
+>f05c01 : Symbol(f05c01, Decl(genericDefaults.ts, 56, 5))
+>f05 : Symbol(f05, Decl(genericDefaults.ts, 52, 41))
+
+const f05c02 = f05(1, 1);
+>f05c02 : Symbol(f05c02, Decl(genericDefaults.ts, 57, 5))
+>f05 : Symbol(f05, Decl(genericDefaults.ts, 52, 41))
+
+const f05c03 = f05<number>();
+>f05c03 : Symbol(f05c03, Decl(genericDefaults.ts, 58, 5))
+>f05 : Symbol(f05, Decl(genericDefaults.ts, 52, 41))
+
+const f05c04 = f05<number>(1);
+>f05c04 : Symbol(f05c04, Decl(genericDefaults.ts, 59, 5))
+>f05 : Symbol(f05, Decl(genericDefaults.ts, 52, 41))
+
+const f05c05 = f05<number>(1, 2);
+>f05c05 : Symbol(f05c05, Decl(genericDefaults.ts, 60, 5))
+>f05 : Symbol(f05, Decl(genericDefaults.ts, 52, 41))
+
+const f05c06 = f05<number, number>();
+>f05c06 : Symbol(f05c06, Decl(genericDefaults.ts, 61, 5))
+>f05 : Symbol(f05, Decl(genericDefaults.ts, 52, 41))
+
+const f05c07 = f05<number, number>(1);
+>f05c07 : Symbol(f05c07, Decl(genericDefaults.ts, 62, 5))
+>f05 : Symbol(f05, Decl(genericDefaults.ts, 52, 41))
+
+const f05c08 = f05<number, number>(1, 2);
+>f05c08 : Symbol(f05c08, Decl(genericDefaults.ts, 63, 5))
+>f05 : Symbol(f05, Decl(genericDefaults.ts, 52, 41))
+
 interface i00<T = number> { a: T; }
->i00 : Symbol(i00, Decl(genericDefaults.ts, 41, 41))
->T : Symbol(T, Decl(genericDefaults.ts, 43, 14))
->a : Symbol(i00.a, Decl(genericDefaults.ts, 43, 27))
->T : Symbol(T, Decl(genericDefaults.ts, 43, 14))
+>i00 : Symbol(i00, Decl(genericDefaults.ts, 63, 41))
+>T : Symbol(T, Decl(genericDefaults.ts, 65, 14))
+>a : Symbol(i00.a, Decl(genericDefaults.ts, 65, 27))
+>T : Symbol(T, Decl(genericDefaults.ts, 65, 14))
 
 const i00c00 = (<i00>x).a;
->i00c00 : Symbol(i00c00, Decl(genericDefaults.ts, 44, 5))
->(<i00>x).a : Symbol(i00.a, Decl(genericDefaults.ts, 43, 27))
->i00 : Symbol(i00, Decl(genericDefaults.ts, 41, 41))
+>i00c00 : Symbol(i00c00, Decl(genericDefaults.ts, 66, 5))
+>(<i00>x).a : Symbol(i00.a, Decl(genericDefaults.ts, 65, 27))
+>i00 : Symbol(i00, Decl(genericDefaults.ts, 63, 41))
 >x : Symbol(x, Decl(genericDefaults.ts, 0, 13))
->a : Symbol(i00.a, Decl(genericDefaults.ts, 43, 27))
+>a : Symbol(i00.a, Decl(genericDefaults.ts, 65, 27))
 
 const i00c01 = (<i00<number>>x).a;
->i00c01 : Symbol(i00c01, Decl(genericDefaults.ts, 45, 5))
->(<i00<number>>x).a : Symbol(i00.a, Decl(genericDefaults.ts, 43, 27))
->i00 : Symbol(i00, Decl(genericDefaults.ts, 41, 41))
+>i00c01 : Symbol(i00c01, Decl(genericDefaults.ts, 67, 5))
+>(<i00<number>>x).a : Symbol(i00.a, Decl(genericDefaults.ts, 65, 27))
+>i00 : Symbol(i00, Decl(genericDefaults.ts, 63, 41))
 >x : Symbol(x, Decl(genericDefaults.ts, 0, 13))
->a : Symbol(i00.a, Decl(genericDefaults.ts, 43, 27))
+>a : Symbol(i00.a, Decl(genericDefaults.ts, 65, 27))
 
 interface i01<T, U = T> { a: [T, U]; }
->i01 : Symbol(i01, Decl(genericDefaults.ts, 45, 34))
->T : Symbol(T, Decl(genericDefaults.ts, 47, 14))
->U : Symbol(U, Decl(genericDefaults.ts, 47, 16))
->T : Symbol(T, Decl(genericDefaults.ts, 47, 14))
->a : Symbol(i01.a, Decl(genericDefaults.ts, 47, 25))
->T : Symbol(T, Decl(genericDefaults.ts, 47, 14))
->U : Symbol(U, Decl(genericDefaults.ts, 47, 16))
+>i01 : Symbol(i01, Decl(genericDefaults.ts, 67, 34))
+>T : Symbol(T, Decl(genericDefaults.ts, 69, 14))
+>U : Symbol(U, Decl(genericDefaults.ts, 69, 16))
+>T : Symbol(T, Decl(genericDefaults.ts, 69, 14))
+>a : Symbol(i01.a, Decl(genericDefaults.ts, 69, 25))
+>T : Symbol(T, Decl(genericDefaults.ts, 69, 14))
+>U : Symbol(U, Decl(genericDefaults.ts, 69, 16))
 
 const i01c00 = (<i01<number>>x).a;
->i01c00 : Symbol(i01c00, Decl(genericDefaults.ts, 48, 5))
->(<i01<number>>x).a : Symbol(i01.a, Decl(genericDefaults.ts, 47, 25))
->i01 : Symbol(i01, Decl(genericDefaults.ts, 45, 34))
+>i01c00 : Symbol(i01c00, Decl(genericDefaults.ts, 70, 5))
+>(<i01<number>>x).a : Symbol(i01.a, Decl(genericDefaults.ts, 69, 25))
+>i01 : Symbol(i01, Decl(genericDefaults.ts, 67, 34))
 >x : Symbol(x, Decl(genericDefaults.ts, 0, 13))
->a : Symbol(i01.a, Decl(genericDefaults.ts, 47, 25))
+>a : Symbol(i01.a, Decl(genericDefaults.ts, 69, 25))
 
 const i01c01 = (<i01<number, string>>x).a;
->i01c01 : Symbol(i01c01, Decl(genericDefaults.ts, 49, 5))
->(<i01<number, string>>x).a : Symbol(i01.a, Decl(genericDefaults.ts, 47, 25))
->i01 : Symbol(i01, Decl(genericDefaults.ts, 45, 34))
+>i01c01 : Symbol(i01c01, Decl(genericDefaults.ts, 71, 5))
+>(<i01<number, string>>x).a : Symbol(i01.a, Decl(genericDefaults.ts, 69, 25))
+>i01 : Symbol(i01, Decl(genericDefaults.ts, 67, 34))
 >x : Symbol(x, Decl(genericDefaults.ts, 0, 13))
->a : Symbol(i01.a, Decl(genericDefaults.ts, 47, 25))
+>a : Symbol(i01.a, Decl(genericDefaults.ts, 69, 25))
 
 interface i02<T extends number, U = T> { a: [T, U]; }
->i02 : Symbol(i02, Decl(genericDefaults.ts, 49, 42))
->T : Symbol(T, Decl(genericDefaults.ts, 51, 14))
->U : Symbol(U, Decl(genericDefaults.ts, 51, 31))
->T : Symbol(T, Decl(genericDefaults.ts, 51, 14))
->a : Symbol(i02.a, Decl(genericDefaults.ts, 51, 40))
->T : Symbol(T, Decl(genericDefaults.ts, 51, 14))
->U : Symbol(U, Decl(genericDefaults.ts, 51, 31))
+>i02 : Symbol(i02, Decl(genericDefaults.ts, 71, 42))
+>T : Symbol(T, Decl(genericDefaults.ts, 73, 14))
+>U : Symbol(U, Decl(genericDefaults.ts, 73, 31))
+>T : Symbol(T, Decl(genericDefaults.ts, 73, 14))
+>a : Symbol(i02.a, Decl(genericDefaults.ts, 73, 40))
+>T : Symbol(T, Decl(genericDefaults.ts, 73, 14))
+>U : Symbol(U, Decl(genericDefaults.ts, 73, 31))
 
 const i02c00 = (<i02<number>>x).a;
->i02c00 : Symbol(i02c00, Decl(genericDefaults.ts, 52, 5))
->(<i02<number>>x).a : Symbol(i02.a, Decl(genericDefaults.ts, 51, 40))
->i02 : Symbol(i02, Decl(genericDefaults.ts, 49, 42))
+>i02c00 : Symbol(i02c00, Decl(genericDefaults.ts, 74, 5))
+>(<i02<number>>x).a : Symbol(i02.a, Decl(genericDefaults.ts, 73, 40))
+>i02 : Symbol(i02, Decl(genericDefaults.ts, 71, 42))
 >x : Symbol(x, Decl(genericDefaults.ts, 0, 13))
->a : Symbol(i02.a, Decl(genericDefaults.ts, 51, 40))
+>a : Symbol(i02.a, Decl(genericDefaults.ts, 73, 40))
 
 const i02c01 = (<i02<1>>x).a;
->i02c01 : Symbol(i02c01, Decl(genericDefaults.ts, 53, 5))
->(<i02<1>>x).a : Symbol(i02.a, Decl(genericDefaults.ts, 51, 40))
->i02 : Symbol(i02, Decl(genericDefaults.ts, 49, 42))
+>i02c01 : Symbol(i02c01, Decl(genericDefaults.ts, 75, 5))
+>(<i02<1>>x).a : Symbol(i02.a, Decl(genericDefaults.ts, 73, 40))
+>i02 : Symbol(i02, Decl(genericDefaults.ts, 71, 42))
 >x : Symbol(x, Decl(genericDefaults.ts, 0, 13))
->a : Symbol(i02.a, Decl(genericDefaults.ts, 51, 40))
+>a : Symbol(i02.a, Decl(genericDefaults.ts, 73, 40))
 
 const i02c02 = (<i02<number, number>>x).a;
->i02c02 : Symbol(i02c02, Decl(genericDefaults.ts, 54, 5))
->(<i02<number, number>>x).a : Symbol(i02.a, Decl(genericDefaults.ts, 51, 40))
->i02 : Symbol(i02, Decl(genericDefaults.ts, 49, 42))
+>i02c02 : Symbol(i02c02, Decl(genericDefaults.ts, 76, 5))
+>(<i02<number, number>>x).a : Symbol(i02.a, Decl(genericDefaults.ts, 73, 40))
+>i02 : Symbol(i02, Decl(genericDefaults.ts, 71, 42))
 >x : Symbol(x, Decl(genericDefaults.ts, 0, 13))
->a : Symbol(i02.a, Decl(genericDefaults.ts, 51, 40))
+>a : Symbol(i02.a, Decl(genericDefaults.ts, 73, 40))
 
 const i02c03 = (<i02<1, number>>x).a;
->i02c03 : Symbol(i02c03, Decl(genericDefaults.ts, 55, 5))
->(<i02<1, number>>x).a : Symbol(i02.a, Decl(genericDefaults.ts, 51, 40))
->i02 : Symbol(i02, Decl(genericDefaults.ts, 49, 42))
+>i02c03 : Symbol(i02c03, Decl(genericDefaults.ts, 77, 5))
+>(<i02<1, number>>x).a : Symbol(i02.a, Decl(genericDefaults.ts, 73, 40))
+>i02 : Symbol(i02, Decl(genericDefaults.ts, 71, 42))
 >x : Symbol(x, Decl(genericDefaults.ts, 0, 13))
->a : Symbol(i02.a, Decl(genericDefaults.ts, 51, 40))
+>a : Symbol(i02.a, Decl(genericDefaults.ts, 73, 40))
 
 const i02c04 = (<i02<number, 1>>x).a;
->i02c04 : Symbol(i02c04, Decl(genericDefaults.ts, 56, 5))
->(<i02<number, 1>>x).a : Symbol(i02.a, Decl(genericDefaults.ts, 51, 40))
->i02 : Symbol(i02, Decl(genericDefaults.ts, 49, 42))
+>i02c04 : Symbol(i02c04, Decl(genericDefaults.ts, 78, 5))
+>(<i02<number, 1>>x).a : Symbol(i02.a, Decl(genericDefaults.ts, 73, 40))
+>i02 : Symbol(i02, Decl(genericDefaults.ts, 71, 42))
 >x : Symbol(x, Decl(genericDefaults.ts, 0, 13))
->a : Symbol(i02.a, Decl(genericDefaults.ts, 51, 40))
+>a : Symbol(i02.a, Decl(genericDefaults.ts, 73, 40))
 
 interface i03<T extends number, U extends T = T> { a: [T, U]; }
->i03 : Symbol(i03, Decl(genericDefaults.ts, 56, 37))
->T : Symbol(T, Decl(genericDefaults.ts, 58, 14))
->U : Symbol(U, Decl(genericDefaults.ts, 58, 31))
->T : Symbol(T, Decl(genericDefaults.ts, 58, 14))
->T : Symbol(T, Decl(genericDefaults.ts, 58, 14))
->a : Symbol(i03.a, Decl(genericDefaults.ts, 58, 50))
->T : Symbol(T, Decl(genericDefaults.ts, 58, 14))
->U : Symbol(U, Decl(genericDefaults.ts, 58, 31))
+>i03 : Symbol(i03, Decl(genericDefaults.ts, 78, 37))
+>T : Symbol(T, Decl(genericDefaults.ts, 80, 14))
+>U : Symbol(U, Decl(genericDefaults.ts, 80, 31))
+>T : Symbol(T, Decl(genericDefaults.ts, 80, 14))
+>T : Symbol(T, Decl(genericDefaults.ts, 80, 14))
+>a : Symbol(i03.a, Decl(genericDefaults.ts, 80, 50))
+>T : Symbol(T, Decl(genericDefaults.ts, 80, 14))
+>U : Symbol(U, Decl(genericDefaults.ts, 80, 31))
 
 const i03c00 = (<i03<number>>x).a;
->i03c00 : Symbol(i03c00, Decl(genericDefaults.ts, 59, 5))
->(<i03<number>>x).a : Symbol(i03.a, Decl(genericDefaults.ts, 58, 50))
->i03 : Symbol(i03, Decl(genericDefaults.ts, 56, 37))
+>i03c00 : Symbol(i03c00, Decl(genericDefaults.ts, 81, 5))
+>(<i03<number>>x).a : Symbol(i03.a, Decl(genericDefaults.ts, 80, 50))
+>i03 : Symbol(i03, Decl(genericDefaults.ts, 78, 37))
 >x : Symbol(x, Decl(genericDefaults.ts, 0, 13))
->a : Symbol(i03.a, Decl(genericDefaults.ts, 58, 50))
+>a : Symbol(i03.a, Decl(genericDefaults.ts, 80, 50))
 
 const i03c01 = (<i03<1>>x).a;
->i03c01 : Symbol(i03c01, Decl(genericDefaults.ts, 60, 5))
->(<i03<1>>x).a : Symbol(i03.a, Decl(genericDefaults.ts, 58, 50))
->i03 : Symbol(i03, Decl(genericDefaults.ts, 56, 37))
+>i03c01 : Symbol(i03c01, Decl(genericDefaults.ts, 82, 5))
+>(<i03<1>>x).a : Symbol(i03.a, Decl(genericDefaults.ts, 80, 50))
+>i03 : Symbol(i03, Decl(genericDefaults.ts, 78, 37))
 >x : Symbol(x, Decl(genericDefaults.ts, 0, 13))
->a : Symbol(i03.a, Decl(genericDefaults.ts, 58, 50))
+>a : Symbol(i03.a, Decl(genericDefaults.ts, 80, 50))
 
 const i03c02 = (<i03<number, number>>x).a;
->i03c02 : Symbol(i03c02, Decl(genericDefaults.ts, 61, 5))
->(<i03<number, number>>x).a : Symbol(i03.a, Decl(genericDefaults.ts, 58, 50))
->i03 : Symbol(i03, Decl(genericDefaults.ts, 56, 37))
+>i03c02 : Symbol(i03c02, Decl(genericDefaults.ts, 83, 5))
+>(<i03<number, number>>x).a : Symbol(i03.a, Decl(genericDefaults.ts, 80, 50))
+>i03 : Symbol(i03, Decl(genericDefaults.ts, 78, 37))
 >x : Symbol(x, Decl(genericDefaults.ts, 0, 13))
->a : Symbol(i03.a, Decl(genericDefaults.ts, 58, 50))
+>a : Symbol(i03.a, Decl(genericDefaults.ts, 80, 50))
 
 const i03c03 = (<i03<1, 1>>x).a;
->i03c03 : Symbol(i03c03, Decl(genericDefaults.ts, 62, 5))
->(<i03<1, 1>>x).a : Symbol(i03.a, Decl(genericDefaults.ts, 58, 50))
->i03 : Symbol(i03, Decl(genericDefaults.ts, 56, 37))
+>i03c03 : Symbol(i03c03, Decl(genericDefaults.ts, 84, 5))
+>(<i03<1, 1>>x).a : Symbol(i03.a, Decl(genericDefaults.ts, 80, 50))
+>i03 : Symbol(i03, Decl(genericDefaults.ts, 78, 37))
 >x : Symbol(x, Decl(genericDefaults.ts, 0, 13))
->a : Symbol(i03.a, Decl(genericDefaults.ts, 58, 50))
+>a : Symbol(i03.a, Decl(genericDefaults.ts, 80, 50))
 
 const i03c04 = (<i03<number, 1>>x).a;
->i03c04 : Symbol(i03c04, Decl(genericDefaults.ts, 63, 5))
->(<i03<number, 1>>x).a : Symbol(i03.a, Decl(genericDefaults.ts, 58, 50))
->i03 : Symbol(i03, Decl(genericDefaults.ts, 56, 37))
+>i03c04 : Symbol(i03c04, Decl(genericDefaults.ts, 85, 5))
+>(<i03<number, 1>>x).a : Symbol(i03.a, Decl(genericDefaults.ts, 80, 50))
+>i03 : Symbol(i03, Decl(genericDefaults.ts, 78, 37))
 >x : Symbol(x, Decl(genericDefaults.ts, 0, 13))
->a : Symbol(i03.a, Decl(genericDefaults.ts, 58, 50))
+>a : Symbol(i03.a, Decl(genericDefaults.ts, 80, 50))
 
 interface Base01<T> { a: T; }
->Base01 : Symbol(Base01, Decl(genericDefaults.ts, 63, 37), Decl(genericDefaults.ts, 68, 13))
->T : Symbol(T, Decl(genericDefaults.ts, 65, 17))
->a : Symbol(Base01.a, Decl(genericDefaults.ts, 65, 21))
->T : Symbol(T, Decl(genericDefaults.ts, 65, 17))
+>Base01 : Symbol(Base01, Decl(genericDefaults.ts, 85, 37), Decl(genericDefaults.ts, 90, 13))
+>T : Symbol(T, Decl(genericDefaults.ts, 87, 17))
+>a : Symbol(Base01.a, Decl(genericDefaults.ts, 87, 21))
+>T : Symbol(T, Decl(genericDefaults.ts, 87, 17))
 
 interface Base01Constructor { new <T = number>(a?: T): Base01<T>; }
->Base01Constructor : Symbol(Base01Constructor, Decl(genericDefaults.ts, 65, 29))
->T : Symbol(T, Decl(genericDefaults.ts, 66, 35))
->a : Symbol(a, Decl(genericDefaults.ts, 66, 47))
->T : Symbol(T, Decl(genericDefaults.ts, 66, 35))
->Base01 : Symbol(Base01, Decl(genericDefaults.ts, 63, 37), Decl(genericDefaults.ts, 68, 13))
->T : Symbol(T, Decl(genericDefaults.ts, 66, 35))
+>Base01Constructor : Symbol(Base01Constructor, Decl(genericDefaults.ts, 87, 29))
+>T : Symbol(T, Decl(genericDefaults.ts, 88, 35))
+>a : Symbol(a, Decl(genericDefaults.ts, 88, 47))
+>T : Symbol(T, Decl(genericDefaults.ts, 88, 35))
+>Base01 : Symbol(Base01, Decl(genericDefaults.ts, 85, 37), Decl(genericDefaults.ts, 90, 13))
+>T : Symbol(T, Decl(genericDefaults.ts, 88, 35))
 
 declare const Base01: Base01Constructor;
->Base01 : Symbol(Base01, Decl(genericDefaults.ts, 63, 37), Decl(genericDefaults.ts, 68, 13))
->Base01Constructor : Symbol(Base01Constructor, Decl(genericDefaults.ts, 65, 29))
+>Base01 : Symbol(Base01, Decl(genericDefaults.ts, 85, 37), Decl(genericDefaults.ts, 90, 13))
+>Base01Constructor : Symbol(Base01Constructor, Decl(genericDefaults.ts, 87, 29))
 
 const Base01c00 = new Base01();
->Base01c00 : Symbol(Base01c00, Decl(genericDefaults.ts, 69, 5))
->Base01 : Symbol(Base01, Decl(genericDefaults.ts, 63, 37), Decl(genericDefaults.ts, 68, 13))
+>Base01c00 : Symbol(Base01c00, Decl(genericDefaults.ts, 91, 5))
+>Base01 : Symbol(Base01, Decl(genericDefaults.ts, 85, 37), Decl(genericDefaults.ts, 90, 13))
 
 const Base01c01 = new Base01(1);
->Base01c01 : Symbol(Base01c01, Decl(genericDefaults.ts, 70, 5))
->Base01 : Symbol(Base01, Decl(genericDefaults.ts, 63, 37), Decl(genericDefaults.ts, 68, 13))
+>Base01c01 : Symbol(Base01c01, Decl(genericDefaults.ts, 92, 5))
+>Base01 : Symbol(Base01, Decl(genericDefaults.ts, 85, 37), Decl(genericDefaults.ts, 90, 13))
 
 const Base01c02 = new Base01<number>();
->Base01c02 : Symbol(Base01c02, Decl(genericDefaults.ts, 71, 5))
->Base01 : Symbol(Base01, Decl(genericDefaults.ts, 63, 37), Decl(genericDefaults.ts, 68, 13))
+>Base01c02 : Symbol(Base01c02, Decl(genericDefaults.ts, 93, 5))
+>Base01 : Symbol(Base01, Decl(genericDefaults.ts, 85, 37), Decl(genericDefaults.ts, 90, 13))
 
 const Base01c03 = new Base01<number>(1);
->Base01c03 : Symbol(Base01c03, Decl(genericDefaults.ts, 72, 5))
->Base01 : Symbol(Base01, Decl(genericDefaults.ts, 63, 37), Decl(genericDefaults.ts, 68, 13))
+>Base01c03 : Symbol(Base01c03, Decl(genericDefaults.ts, 94, 5))
+>Base01 : Symbol(Base01, Decl(genericDefaults.ts, 85, 37), Decl(genericDefaults.ts, 90, 13))
 
 declare class Derived01<T> extends Base01<T> { }
->Derived01 : Symbol(Derived01, Decl(genericDefaults.ts, 72, 40))
->T : Symbol(T, Decl(genericDefaults.ts, 74, 24))
->Base01 : Symbol(Base01, Decl(genericDefaults.ts, 63, 37), Decl(genericDefaults.ts, 68, 13))
->T : Symbol(T, Decl(genericDefaults.ts, 74, 24))
+>Derived01 : Symbol(Derived01, Decl(genericDefaults.ts, 94, 40))
+>T : Symbol(T, Decl(genericDefaults.ts, 96, 24))
+>Base01 : Symbol(Base01, Decl(genericDefaults.ts, 85, 37), Decl(genericDefaults.ts, 90, 13))
+>T : Symbol(T, Decl(genericDefaults.ts, 96, 24))
 
 const Derived01c00 = new Derived01();
->Derived01c00 : Symbol(Derived01c00, Decl(genericDefaults.ts, 75, 5))
->Derived01 : Symbol(Derived01, Decl(genericDefaults.ts, 72, 40))
+>Derived01c00 : Symbol(Derived01c00, Decl(genericDefaults.ts, 97, 5))
+>Derived01 : Symbol(Derived01, Decl(genericDefaults.ts, 94, 40))
 
 const Derived01c01 = new Derived01(1);
->Derived01c01 : Symbol(Derived01c01, Decl(genericDefaults.ts, 76, 5))
->Derived01 : Symbol(Derived01, Decl(genericDefaults.ts, 72, 40))
+>Derived01c01 : Symbol(Derived01c01, Decl(genericDefaults.ts, 98, 5))
+>Derived01 : Symbol(Derived01, Decl(genericDefaults.ts, 94, 40))
 
 const Derived01c02 = new Derived01<number>();
->Derived01c02 : Symbol(Derived01c02, Decl(genericDefaults.ts, 77, 5))
->Derived01 : Symbol(Derived01, Decl(genericDefaults.ts, 72, 40))
+>Derived01c02 : Symbol(Derived01c02, Decl(genericDefaults.ts, 99, 5))
+>Derived01 : Symbol(Derived01, Decl(genericDefaults.ts, 94, 40))
 
 const Derived01c03 = new Derived01<number>(1);
->Derived01c03 : Symbol(Derived01c03, Decl(genericDefaults.ts, 78, 5))
->Derived01 : Symbol(Derived01, Decl(genericDefaults.ts, 72, 40))
+>Derived01c03 : Symbol(Derived01c03, Decl(genericDefaults.ts, 100, 5))
+>Derived01 : Symbol(Derived01, Decl(genericDefaults.ts, 94, 40))
 
 declare class Derived02<T = string> extends Base01<T> { }
->Derived02 : Symbol(Derived02, Decl(genericDefaults.ts, 78, 46))
->T : Symbol(T, Decl(genericDefaults.ts, 80, 24))
->Base01 : Symbol(Base01, Decl(genericDefaults.ts, 63, 37), Decl(genericDefaults.ts, 68, 13))
->T : Symbol(T, Decl(genericDefaults.ts, 80, 24))
+>Derived02 : Symbol(Derived02, Decl(genericDefaults.ts, 100, 46))
+>T : Symbol(T, Decl(genericDefaults.ts, 102, 24))
+>Base01 : Symbol(Base01, Decl(genericDefaults.ts, 85, 37), Decl(genericDefaults.ts, 90, 13))
+>T : Symbol(T, Decl(genericDefaults.ts, 102, 24))
 
 const Derived02c00 = new Derived02();
->Derived02c00 : Symbol(Derived02c00, Decl(genericDefaults.ts, 81, 5))
->Derived02 : Symbol(Derived02, Decl(genericDefaults.ts, 78, 46))
+>Derived02c00 : Symbol(Derived02c00, Decl(genericDefaults.ts, 103, 5))
+>Derived02 : Symbol(Derived02, Decl(genericDefaults.ts, 100, 46))
 
 const Derived02c01 = new Derived02(1);
->Derived02c01 : Symbol(Derived02c01, Decl(genericDefaults.ts, 82, 5))
->Derived02 : Symbol(Derived02, Decl(genericDefaults.ts, 78, 46))
+>Derived02c01 : Symbol(Derived02c01, Decl(genericDefaults.ts, 104, 5))
+>Derived02 : Symbol(Derived02, Decl(genericDefaults.ts, 100, 46))
 
 const Derived02c02 = new Derived02<number>();
->Derived02c02 : Symbol(Derived02c02, Decl(genericDefaults.ts, 83, 5))
->Derived02 : Symbol(Derived02, Decl(genericDefaults.ts, 78, 46))
+>Derived02c02 : Symbol(Derived02c02, Decl(genericDefaults.ts, 105, 5))
+>Derived02 : Symbol(Derived02, Decl(genericDefaults.ts, 100, 46))
 
 const Derived02c03 = new Derived02<number>(1);
->Derived02c03 : Symbol(Derived02c03, Decl(genericDefaults.ts, 84, 5))
->Derived02 : Symbol(Derived02, Decl(genericDefaults.ts, 78, 46))
+>Derived02c03 : Symbol(Derived02c03, Decl(genericDefaults.ts, 106, 5))
+>Derived02 : Symbol(Derived02, Decl(genericDefaults.ts, 100, 46))
 
diff --git a/tests/baselines/reference/genericDefaults.types b/tests/baselines/reference/genericDefaults.types
index c693d4e4048d0..7f50e03744c04 100644
--- a/tests/baselines/reference/genericDefaults.types
+++ b/tests/baselines/reference/genericDefaults.types
@@ -242,6 +242,140 @@ const f03c08 = f03<number, number>(1, 2);
 >1 : 1
 >2 : 2
 
+declare function f04<T, U = T | { a: number }>(a?: T, b?: U): [T, U];
+>f04 : <T, U = T | { a: number; }>(a?: T, b?: U) => [T, U]
+>T : T
+>U : U
+>T : T
+>a : number
+>a : T
+>T : T
+>b : U
+>U : U
+>T : T
+>U : U
+
+const f04c00 = f04();
+>f04c00 : [{}, {} | { a: number; }]
+>f04() : [{}, {} | { a: number; }]
+>f04 : <T, U = T | { a: number; }>(a?: T, b?: U) => [T, U]
+
+const f04c01 = f04(1);
+>f04c01 : [number, number | { a: number; }]
+>f04(1) : [number, number | { a: number; }]
+>f04 : <T, U = T | { a: number; }>(a?: T, b?: U) => [T, U]
+>1 : 1
+
+const f04c02 = f04(1, 1);
+>f04c02 : [number, number]
+>f04(1, 1) : [number, number]
+>f04 : <T, U = T | { a: number; }>(a?: T, b?: U) => [T, U]
+>1 : 1
+>1 : 1
+
+const f04c03 = f04<number>();
+>f04c03 : [number, number | { a: number; }]
+>f04<number>() : [number, number | { a: number; }]
+>f04 : <T, U = T | { a: number; }>(a?: T, b?: U) => [T, U]
+
+const f04c04 = f04<number>(1);
+>f04c04 : [number, number | { a: number; }]
+>f04<number>(1) : [number, number | { a: number; }]
+>f04 : <T, U = T | { a: number; }>(a?: T, b?: U) => [T, U]
+>1 : 1
+
+const f04c05 = f04<number>(1, 2);
+>f04c05 : [number, number]
+>f04<number>(1, 2) : [number, number]
+>f04 : <T, U = T | { a: number; }>(a?: T, b?: U) => [T, U]
+>1 : 1
+>2 : 2
+
+const f04c06 = f04<number, number>();
+>f04c06 : [number, number]
+>f04<number, number>() : [number, number]
+>f04 : <T, U = T | { a: number; }>(a?: T, b?: U) => [T, U]
+
+const f04c07 = f04<number, number>(1);
+>f04c07 : [number, number]
+>f04<number, number>(1) : [number, number]
+>f04 : <T, U = T | { a: number; }>(a?: T, b?: U) => [T, U]
+>1 : 1
+
+const f04c08 = f04<number, number>(1, 2);
+>f04c08 : [number, number]
+>f04<number, number>(1, 2) : [number, number]
+>f04 : <T, U = T | { a: number; }>(a?: T, b?: U) => [T, U]
+>1 : 1
+>2 : 2
+
+declare function f05<T, U = T & { a: number }>(a?: T, b?: U): [T, U];
+>f05 : <T, U = T & { a: number; }>(a?: T, b?: U) => [T, U]
+>T : T
+>U : U
+>T : T
+>a : number
+>a : T
+>T : T
+>b : U
+>U : U
+>T : T
+>U : U
+
+const f05c00 = f05();
+>f05c00 : [{}, {} & { a: number; }]
+>f05() : [{}, {} & { a: number; }]
+>f05 : <T, U = T & { a: number; }>(a?: T, b?: U) => [T, U]
+
+const f05c01 = f05(1);
+>f05c01 : [number, number & { a: number; }]
+>f05(1) : [number, number & { a: number; }]
+>f05 : <T, U = T & { a: number; }>(a?: T, b?: U) => [T, U]
+>1 : 1
+
+const f05c02 = f05(1, 1);
+>f05c02 : [number, number]
+>f05(1, 1) : [number, number]
+>f05 : <T, U = T & { a: number; }>(a?: T, b?: U) => [T, U]
+>1 : 1
+>1 : 1
+
+const f05c03 = f05<number>();
+>f05c03 : [number, number & { a: number; }]
+>f05<number>() : [number, number & { a: number; }]
+>f05 : <T, U = T & { a: number; }>(a?: T, b?: U) => [T, U]
+
+const f05c04 = f05<number>(1);
+>f05c04 : [number, number & { a: number; }]
+>f05<number>(1) : [number, number & { a: number; }]
+>f05 : <T, U = T & { a: number; }>(a?: T, b?: U) => [T, U]
+>1 : 1
+
+const f05c05 = f05<number>(1, 2);
+>f05c05 : [number, number]
+>f05<number>(1, 2) : [number, number]
+>f05 : <T, U = T & { a: number; }>(a?: T, b?: U) => [T, U]
+>1 : 1
+>2 : 2
+
+const f05c06 = f05<number, number>();
+>f05c06 : [number, number]
+>f05<number, number>() : [number, number]
+>f05 : <T, U = T & { a: number; }>(a?: T, b?: U) => [T, U]
+
+const f05c07 = f05<number, number>(1);
+>f05c07 : [number, number]
+>f05<number, number>(1) : [number, number]
+>f05 : <T, U = T & { a: number; }>(a?: T, b?: U) => [T, U]
+>1 : 1
+
+const f05c08 = f05<number, number>(1, 2);
+>f05c08 : [number, number]
+>f05<number, number>(1, 2) : [number, number]
+>f05 : <T, U = T & { a: number; }>(a?: T, b?: U) => [T, U]
+>1 : 1
+>2 : 2
+
 interface i00<T = number> { a: T; }
 >i00 : i00<T>
 >T : T
diff --git a/tests/baselines/reference/genericDefaultsErrors.errors.txt b/tests/baselines/reference/genericDefaultsErrors.errors.txt
index 5e19e25f270e9..aaf1f0b6cf014 100644
--- a/tests/baselines/reference/genericDefaultsErrors.errors.txt
+++ b/tests/baselines/reference/genericDefaultsErrors.errors.txt
@@ -7,25 +7,33 @@ tests/cases/compiler/genericDefaultsErrors.ts(8,59): error TS2344: Type 'T' does
   Type 'string' is not assignable to type 'number'.
 tests/cases/compiler/genericDefaultsErrors.ts(9,44): error TS2344: Type 'T' does not satisfy the constraint 'number'.
 tests/cases/compiler/genericDefaultsErrors.ts(10,39): error TS2344: Type 'number' does not satisfy the constraint 'T'.
-tests/cases/compiler/genericDefaultsErrors.ts(14,1): error TS2346: Supplied parameters do not match any signature of call target.
-tests/cases/compiler/genericDefaultsErrors.ts(17,1): error TS2346: Supplied parameters do not match any signature of call target.
-tests/cases/compiler/genericDefaultsErrors.ts(20,11): error TS2428: All declarations of 'i00' must have identical type parameters.
-tests/cases/compiler/genericDefaultsErrors.ts(23,11): error TS2428: All declarations of 'i01' must have identical type parameters.
-tests/cases/compiler/genericDefaultsErrors.ts(25,19): error TS2706: Type parameter 'T' has a circular default.
-tests/cases/compiler/genericDefaultsErrors.ts(26,19): error TS2706: Type parameter 'T' has a circular default.
-tests/cases/compiler/genericDefaultsErrors.ts(26,26): error TS2706: Type parameter 'U' has a circular default.
-tests/cases/compiler/genericDefaultsErrors.ts(27,22): error TS2705: Required type parameters may not follow optional type parameters
-tests/cases/compiler/genericDefaultsErrors.ts(28,34): error TS2344: Type 'number' does not satisfy the constraint 'string'.
-tests/cases/compiler/genericDefaultsErrors.ts(29,52): error TS2344: Type 'T' does not satisfy the constraint 'number'.
+tests/cases/compiler/genericDefaultsErrors.ts(11,26): error TS2706: Type parameter 'T' has a circular default.
+tests/cases/compiler/genericDefaultsErrors.ts(11,33): error TS2706: Type parameter 'U' has a circular default.
+tests/cases/compiler/genericDefaultsErrors.ts(12,26): error TS2706: Type parameter 'T' has a circular default.
+tests/cases/compiler/genericDefaultsErrors.ts(12,33): error TS2706: Type parameter 'U' has a circular default.
+tests/cases/compiler/genericDefaultsErrors.ts(13,26): error TS2706: Type parameter 'T' has a circular default.
+tests/cases/compiler/genericDefaultsErrors.ts(13,33): error TS2706: Type parameter 'U' has a circular default.
+tests/cases/compiler/genericDefaultsErrors.ts(14,26): error TS2706: Type parameter 'T' has a circular default.
+tests/cases/compiler/genericDefaultsErrors.ts(14,33): error TS2706: Type parameter 'U' has a circular default.
+tests/cases/compiler/genericDefaultsErrors.ts(18,1): error TS2346: Supplied parameters do not match any signature of call target.
+tests/cases/compiler/genericDefaultsErrors.ts(21,1): error TS2346: Supplied parameters do not match any signature of call target.
+tests/cases/compiler/genericDefaultsErrors.ts(24,11): error TS2428: All declarations of 'i00' must have identical type parameters.
+tests/cases/compiler/genericDefaultsErrors.ts(27,11): error TS2428: All declarations of 'i01' must have identical type parameters.
+tests/cases/compiler/genericDefaultsErrors.ts(29,19): error TS2706: Type parameter 'T' has a circular default.
+tests/cases/compiler/genericDefaultsErrors.ts(30,19): error TS2706: Type parameter 'T' has a circular default.
+tests/cases/compiler/genericDefaultsErrors.ts(30,26): error TS2706: Type parameter 'U' has a circular default.
+tests/cases/compiler/genericDefaultsErrors.ts(31,22): error TS2705: Required type parameters may not follow optional type parameters
+tests/cases/compiler/genericDefaultsErrors.ts(32,34): error TS2344: Type 'number' does not satisfy the constraint 'string'.
+tests/cases/compiler/genericDefaultsErrors.ts(33,52): error TS2344: Type 'T' does not satisfy the constraint 'number'.
   Type 'string' is not assignable to type 'number'.
-tests/cases/compiler/genericDefaultsErrors.ts(30,37): error TS2344: Type 'T' does not satisfy the constraint 'number'.
-tests/cases/compiler/genericDefaultsErrors.ts(31,32): error TS2344: Type 'number' does not satisfy the constraint 'T'.
-tests/cases/compiler/genericDefaultsErrors.ts(34,15): error TS2707: Generic type 'i09<T, U, V>' requires between 2 and 3 type arguments
-tests/cases/compiler/genericDefaultsErrors.ts(35,15): error TS2707: Generic type 'i09<T, U, V>' requires between 2 and 3 type arguments
+tests/cases/compiler/genericDefaultsErrors.ts(34,37): error TS2344: Type 'T' does not satisfy the constraint 'number'.
+tests/cases/compiler/genericDefaultsErrors.ts(35,32): error TS2344: Type 'number' does not satisfy the constraint 'T'.
 tests/cases/compiler/genericDefaultsErrors.ts(38,15): error TS2707: Generic type 'i09<T, U, V>' requires between 2 and 3 type arguments
+tests/cases/compiler/genericDefaultsErrors.ts(39,15): error TS2707: Generic type 'i09<T, U, V>' requires between 2 and 3 type arguments
+tests/cases/compiler/genericDefaultsErrors.ts(42,15): error TS2707: Generic type 'i09<T, U, V>' requires between 2 and 3 type arguments
 
 
-==== tests/cases/compiler/genericDefaultsErrors.ts (23 errors) ====
+==== tests/cases/compiler/genericDefaultsErrors.ts (31 errors) ====
     
     declare const x: any;
     
@@ -53,15 +61,35 @@ tests/cases/compiler/genericDefaultsErrors.ts(38,15): error TS2707: Generic type
     declare function f06<T, U extends T = number>(): void;
                                           ~~~~~~
 !!! error TS2344: Type 'number' does not satisfy the constraint 'T'.
+    declare function f07<T = U, U = T | { a: number }>(): void;
+                             ~
+!!! error TS2706: Type parameter 'T' has a circular default.
+                                    ~~~~~~~~~~~~~~~~~
+!!! error TS2706: Type parameter 'U' has a circular default.
+    declare function f08<T = U, U = T & { a: number }>(): void;
+                             ~
+!!! error TS2706: Type parameter 'T' has a circular default.
+                                    ~~~~~~~~~~~~~~~~~
+!!! error TS2706: Type parameter 'U' has a circular default.
+    declare function f09<T = U, U = T | { a: number }>(): void;
+                             ~
+!!! error TS2706: Type parameter 'T' has a circular default.
+                                    ~~~~~~~~~~~~~~~~~
+!!! error TS2706: Type parameter 'U' has a circular default.
+    declare function f10<T = U, U = T & { a: number }>(): void;
+                             ~
+!!! error TS2706: Type parameter 'T' has a circular default.
+                                    ~~~~~~~~~~~~~~~~~
+!!! error TS2706: Type parameter 'U' has a circular default.
     
-    declare function f07<T, U, V = number>(): void;
-    f07(); // ok
-    f07<1>(); // error
+    declare function f11<T, U, V = number>(): void;
+    f11(); // ok
+    f11<1>(); // error
     ~~~~~~~~
 !!! error TS2346: Supplied parameters do not match any signature of call target.
-    f07<1, 2>(); // ok
-    f07<1, 2, 3>(); // ok
-    f07<1, 2, 3, 4>(); // error
+    f11<1, 2>(); // ok
+    f11<1, 2, 3>(); // ok
+    f11<1, 2, 3, 4>(); // error
     ~~~~~~~~~~~~~~~~~
 !!! error TS2346: Supplied parameters do not match any signature of call target.
     
diff --git a/tests/baselines/reference/genericDefaultsErrors.js b/tests/baselines/reference/genericDefaultsErrors.js
index 9615ad2e36299..6a624fae4d483 100644
--- a/tests/baselines/reference/genericDefaultsErrors.js
+++ b/tests/baselines/reference/genericDefaultsErrors.js
@@ -9,13 +9,17 @@ declare function f03<T extends string = number>(): void;
 declare function f04<T extends string, U extends number = T>(): void;
 declare function f05<T, U extends number = T>(): void;
 declare function f06<T, U extends T = number>(): void;
+declare function f07<T = U, U = T | { a: number }>(): void;
+declare function f08<T = U, U = T & { a: number }>(): void;
+declare function f09<T = U, U = T | { a: number }>(): void;
+declare function f10<T = U, U = T & { a: number }>(): void;
 
-declare function f07<T, U, V = number>(): void;
-f07(); // ok
-f07<1>(); // error
-f07<1, 2>(); // ok
-f07<1, 2, 3>(); // ok
-f07<1, 2, 3, 4>(); // error
+declare function f11<T, U, V = number>(): void;
+f11(); // ok
+f11<1>(); // error
+f11<1, 2>(); // ok
+f11<1, 2, 3>(); // ok
+f11<1, 2, 3, 4>(); // error
 
 interface i00<T> { }
 interface i00<T = number> { }
@@ -39,11 +43,11 @@ type i09t03 = i09<1, 2, 3>; // ok
 type i09t04 = i09<1, 2, 3, 4>; // error
 
 //// [genericDefaultsErrors.js]
-f07(); // ok
-f07(); // error
-f07(); // ok
-f07(); // ok
-f07(); // error
+f11(); // ok
+f11(); // error
+f11(); // ok
+f11(); // ok
+f11(); // error
 
 
 //// [genericDefaultsErrors.d.ts]
@@ -55,7 +59,19 @@ declare function f03<T extends string = number>(): void;
 declare function f04<T extends string, U extends number = T>(): void;
 declare function f05<T, U extends number = T>(): void;
 declare function f06<T, U extends T = number>(): void;
-declare function f07<T, U, V = number>(): void;
+declare function f07<T = U, U = T | {
+    a: number;
+}>(): void;
+declare function f08<T = U, U = T & {
+    a: number;
+}>(): void;
+declare function f09<T = U, U = T | {
+    a: number;
+}>(): void;
+declare function f10<T = U, U = T & {
+    a: number;
+}>(): void;
+declare function f11<T, U, V = number>(): void;
 interface i00<T> {
 }
 interface i00<T = number> {
diff --git a/tests/cases/compiler/genericDefaults.ts b/tests/cases/compiler/genericDefaults.ts
index 9ab0ede05b6e8..abba8f2d8d673 100644
--- a/tests/cases/compiler/genericDefaults.ts
+++ b/tests/cases/compiler/genericDefaults.ts
@@ -42,6 +42,28 @@ const f03c06 = f03<number, number>();
 const f03c07 = f03<number, number>(1);
 const f03c08 = f03<number, number>(1, 2);
 
+declare function f04<T, U = T | { a: number }>(a?: T, b?: U): [T, U];
+const f04c00 = f04();
+const f04c01 = f04(1);
+const f04c02 = f04(1, 1);
+const f04c03 = f04<number>();
+const f04c04 = f04<number>(1);
+const f04c05 = f04<number>(1, 2);
+const f04c06 = f04<number, number>();
+const f04c07 = f04<number, number>(1);
+const f04c08 = f04<number, number>(1, 2);
+
+declare function f05<T, U = T & { a: number }>(a?: T, b?: U): [T, U];
+const f05c00 = f05();
+const f05c01 = f05(1);
+const f05c02 = f05(1, 1);
+const f05c03 = f05<number>();
+const f05c04 = f05<number>(1);
+const f05c05 = f05<number>(1, 2);
+const f05c06 = f05<number, number>();
+const f05c07 = f05<number, number>(1);
+const f05c08 = f05<number, number>(1, 2);
+
 interface i00<T = number> { a: T; }
 const i00c00 = (<i00>x).a;
 const i00c01 = (<i00<number>>x).a;
diff --git a/tests/cases/compiler/genericDefaultsErrors.ts b/tests/cases/compiler/genericDefaultsErrors.ts
index 470b4998e926e..e7fb7be81aeed 100644
--- a/tests/cases/compiler/genericDefaultsErrors.ts
+++ b/tests/cases/compiler/genericDefaultsErrors.ts
@@ -9,13 +9,17 @@ declare function f03<T extends string = number>(): void;
 declare function f04<T extends string, U extends number = T>(): void;
 declare function f05<T, U extends number = T>(): void;
 declare function f06<T, U extends T = number>(): void;
+declare function f07<T = U, U = T | { a: number }>(): void;
+declare function f08<T = U, U = T & { a: number }>(): void;
+declare function f09<T = U, U = T | { a: number }>(): void;
+declare function f10<T = U, U = T & { a: number }>(): void;
 
-declare function f07<T, U, V = number>(): void;
-f07(); // ok
-f07<1>(); // error
-f07<1, 2>(); // ok
-f07<1, 2, 3>(); // ok
-f07<1, 2, 3, 4>(); // error
+declare function f11<T, U, V = number>(): void;
+f11(); // ok
+f11<1>(); // error
+f11<1, 2>(); // ok
+f11<1, 2, 3>(); // ok
+f11<1, 2, 3, 4>(); // error
 
 interface i00<T> { }
 interface i00<T = number> { }