diff --git a/src/lib/es5.d.ts b/src/lib/es5.d.ts
index 24e2c489197c3..c28d21414218e 100644
--- a/src/lib/es5.d.ts
+++ b/src/lib/es5.d.ts
@@ -1138,7 +1138,7 @@ interface ReadonlyArray<T> {
      * @param callbackfn A function that accepts up to three arguments. The map method calls the callbackfn function one time for each element in the array.
      * @param thisArg An object to which the this keyword can refer in the callbackfn function. If thisArg is omitted, undefined is used as the this value.
      */
-    map<U>(callbackfn: (value: T, index: number, array: readonly T[]) => U, thisArg?: any): U[];
+    map<U>(callbackfn: (value: T, index: number, array: readonly T[]) => U, thisArg?: any): { -readonly [P in keyof this]: U } extends U[] ? { -readonly [P in keyof this]: U } : U[];
     /**
      * Returns the elements of an array that meet the condition specified in a callback function.
      * @param callbackfn A function that accepts up to three arguments. The filter method calls the callbackfn function one time for each element in the array.
@@ -1308,7 +1308,7 @@ interface Array<T> {
      * @param callbackfn A function that accepts up to three arguments. The map method calls the callbackfn function one time for each element in the array.
      * @param thisArg An object to which the this keyword can refer in the callbackfn function. If thisArg is omitted, undefined is used as the this value.
      */
-    map<U>(callbackfn: (value: T, index: number, array: T[]) => U, thisArg?: any): U[];
+    map<U>(callbackfn: (value: T, index: number, array: T[]) => U, thisArg?: any): { -readonly [P in keyof this]: U } extends U[] ? { -readonly [P in keyof this]: U } : U[];
     /**
      * Returns the elements of an array that meet the condition specified in a callback function.
      * @param callbackfn A function that accepts up to three arguments. The filter method calls the callbackfn function one time for each element in the array.
diff --git a/tests/baselines/reference/arityAndOrderCompatibility01.errors.txt b/tests/baselines/reference/arityAndOrderCompatibility01.errors.txt
index 31caaef42283b..aa1451185ef82 100644
--- a/tests/baselines/reference/arityAndOrderCompatibility01.errors.txt
+++ b/tests/baselines/reference/arityAndOrderCompatibility01.errors.txt
@@ -1,4 +1,5 @@
 tests/cases/conformance/types/tuple/arityAndOrderCompatibility01.ts(15,12): error TS2493: Tuple type '[string, number]' of length '2' has no element at index '2'.
+tests/cases/conformance/types/tuple/arityAndOrderCompatibility01.ts(16,5): error TS2461: Type 'StrNum' is not an array type.
 tests/cases/conformance/types/tuple/arityAndOrderCompatibility01.ts(17,5): error TS2461: Type '{ 0: string; 1: number; length: 2; }' is not an array type.
 tests/cases/conformance/types/tuple/arityAndOrderCompatibility01.ts(18,5): error TS2741: Property '2' is missing in type '[string, number]' but required in type '[number, number, number]'.
 tests/cases/conformance/types/tuple/arityAndOrderCompatibility01.ts(19,5): error TS2741: Property '2' is missing in type 'StrNum' but required in type '[number, number, number]'.
@@ -28,7 +29,7 @@ tests/cases/conformance/types/tuple/arityAndOrderCompatibility01.ts(31,5): error
 tests/cases/conformance/types/tuple/arityAndOrderCompatibility01.ts(32,5): error TS2322: Type '{ 0: string; 1: number; length: 2; }' is not assignable to type '[number, string]'.
 
 
-==== tests/cases/conformance/types/tuple/arityAndOrderCompatibility01.ts (17 errors) ====
+==== tests/cases/conformance/types/tuple/arityAndOrderCompatibility01.ts (18 errors) ====
     interface StrNum extends Array<string|number> {
         0: string;
         1: number;
@@ -47,6 +48,8 @@ tests/cases/conformance/types/tuple/arityAndOrderCompatibility01.ts(32,5): error
                ~
 !!! error TS2493: Tuple type '[string, number]' of length '2' has no element at index '2'.
     var [d, e, f] = y;
+        ~~~~~~~~~
+!!! error TS2461: Type 'StrNum' is not an array type.
     var [g, h, i] = z;
         ~~~~~~~~~
 !!! error TS2461: Type '{ 0: string; 1: number; length: 2; }' is not an array type.
diff --git a/tests/baselines/reference/arityAndOrderCompatibility01.types b/tests/baselines/reference/arityAndOrderCompatibility01.types
index aa658ba762934..44debb57aceeb 100644
--- a/tests/baselines/reference/arityAndOrderCompatibility01.types
+++ b/tests/baselines/reference/arityAndOrderCompatibility01.types
@@ -36,9 +36,9 @@ var [a, b, c] = x;
 >x : [string, number]
 
 var [d, e, f] = y;
->d : string
->e : number
->f : string | number
+>d : any
+>e : any
+>f : any
 >y : StrNum
 
 var [g, h, i] = z;
diff --git a/tests/baselines/reference/arrayOfSubtypeIsAssignableToReadonlyArray.errors.txt b/tests/baselines/reference/arrayOfSubtypeIsAssignableToReadonlyArray.errors.txt
index 66b3c2c869106..f9b49f79389c1 100644
--- a/tests/baselines/reference/arrayOfSubtypeIsAssignableToReadonlyArray.errors.txt
+++ b/tests/baselines/reference/arrayOfSubtypeIsAssignableToReadonlyArray.errors.txt
@@ -1,12 +1,29 @@
 tests/cases/compiler/arrayOfSubtypeIsAssignableToReadonlyArray.ts(13,1): error TS2322: Type 'A[]' is not assignable to type 'readonly B[]'.
   Property 'b' is missing in type 'A' but required in type 'B'.
+tests/cases/compiler/arrayOfSubtypeIsAssignableToReadonlyArray.ts(15,1): error TS2322: Type 'C<A>' is not assignable to type 'readonly A[]'.
+  The types returned by 'map(...)' are incompatible between these types.
+    Type '{ [x: number]: U; c: U; length: U; toString: U; toLocaleString: U; pop: U; push: U; concat: U; join: U; reverse: U; shift: U; slice: U; sort: U; splice: U; unshift: U; indexOf: U; lastIndexOf: U; every: U; some: U; forEach: U; map: U; filter: U; reduce: U; reduceRight: U; } extends U[] ? { [x: number]: U; c: U; length: U; toString: U; toLocaleString: U; pop: U; push: U; concat: U; join: U; reverse: U; shift: U; slice: U; sort: U; splice: U; unshift: U; indexOf: U; lastIndexOf: U; every: U; some: U; forEach: U; map: U; filter: U; reduce: U; reduceRight: U; } : U[]' is not assignable to type 'U[]'.
+      Type 'U[] | { [x: number]: U; c: U; length: U; toString: U; toLocaleString: U; pop: U; push: U; concat: U; join: U; reverse: U; shift: U; slice: U; sort: U; splice: U; unshift: U; indexOf: U; lastIndexOf: U; every: U; some: U; forEach: U; map: U; filter: U; reduce: U; reduceRight: U; }' is not assignable to type 'U[]'.
+        Type '{ [x: number]: U; c: U; length: U; toString: U; toLocaleString: U; pop: U; push: U; concat: U; join: U; reverse: U; shift: U; slice: U; sort: U; splice: U; unshift: U; indexOf: U; lastIndexOf: U; every: U; some: U; forEach: U; map: U; filter: U; reduce: U; reduceRight: U; }' is not assignable to type 'U[]'.
+          Types of property 'length' are incompatible.
+            Type 'U' is not assignable to type 'number'.
+tests/cases/compiler/arrayOfSubtypeIsAssignableToReadonlyArray.ts(16,1): error TS2322: Type 'C<B>' is not assignable to type 'readonly A[]'.
+  The types returned by 'map(...)' are incompatible between these types.
+    Type '{ [x: number]: U; c: U; length: U; toString: U; toLocaleString: U; pop: U; push: U; concat: U; join: U; reverse: U; shift: U; slice: U; sort: U; splice: U; unshift: U; indexOf: U; lastIndexOf: U; every: U; some: U; forEach: U; map: U; filter: U; reduce: U; reduceRight: U; } extends U[] ? { [x: number]: U; c: U; length: U; toString: U; toLocaleString: U; pop: U; push: U; concat: U; join: U; reverse: U; shift: U; slice: U; sort: U; splice: U; unshift: U; indexOf: U; lastIndexOf: U; every: U; some: U; forEach: U; map: U; filter: U; reduce: U; reduceRight: U; } : U[]' is not assignable to type 'U[]'.
+      Type 'U[] | { [x: number]: U; c: U; length: U; toString: U; toLocaleString: U; pop: U; push: U; concat: U; join: U; reverse: U; shift: U; slice: U; sort: U; splice: U; unshift: U; indexOf: U; lastIndexOf: U; every: U; some: U; forEach: U; map: U; filter: U; reduce: U; reduceRight: U; }' is not assignable to type 'U[]'.
+        Type '{ [x: number]: U; c: U; length: U; toString: U; toLocaleString: U; pop: U; push: U; concat: U; join: U; reverse: U; shift: U; slice: U; sort: U; splice: U; unshift: U; indexOf: U; lastIndexOf: U; every: U; some: U; forEach: U; map: U; filter: U; reduce: U; reduceRight: U; }' is not assignable to type 'U[]'.
+          Types of property 'length' are incompatible.
+            Type 'U' is not assignable to type 'number'.
+tests/cases/compiler/arrayOfSubtypeIsAssignableToReadonlyArray.ts(17,1): error TS2322: Type 'C<B>' is not assignable to type 'readonly B[]'.
+  The types returned by 'map(...)' are incompatible between these types.
+    Type '{ [x: number]: U; c: U; length: U; toString: U; toLocaleString: U; pop: U; push: U; concat: U; join: U; reverse: U; shift: U; slice: U; sort: U; splice: U; unshift: U; indexOf: U; lastIndexOf: U; every: U; some: U; forEach: U; map: U; filter: U; reduce: U; reduceRight: U; } extends U[] ? { [x: number]: U; c: U; length: U; toString: U; toLocaleString: U; pop: U; push: U; concat: U; join: U; reverse: U; shift: U; slice: U; sort: U; splice: U; unshift: U; indexOf: U; lastIndexOf: U; every: U; some: U; forEach: U; map: U; filter: U; reduce: U; reduceRight: U; } : U[]' is not assignable to type 'U[]'.
 tests/cases/compiler/arrayOfSubtypeIsAssignableToReadonlyArray.ts(18,1): error TS2322: Type 'C<A>' is not assignable to type 'readonly B[]'.
   The types returned by 'concat(...)' are incompatible between these types.
     Type 'A[]' is not assignable to type 'B[]'.
       Type 'A' is not assignable to type 'B'.
 
 
-==== tests/cases/compiler/arrayOfSubtypeIsAssignableToReadonlyArray.ts (2 errors) ====
+==== tests/cases/compiler/arrayOfSubtypeIsAssignableToReadonlyArray.ts (5 errors) ====
     class A { a }
     class B extends A { b }
     class C<T> extends Array<T> { c }
@@ -26,8 +43,28 @@ tests/cases/compiler/arrayOfSubtypeIsAssignableToReadonlyArray.ts(18,1): error T
 !!! related TS2728 tests/cases/compiler/arrayOfSubtypeIsAssignableToReadonlyArray.ts:2:21: 'b' is declared here.
     
     rra = cra;
+    ~~~
+!!! error TS2322: Type 'C<A>' is not assignable to type 'readonly A[]'.
+!!! error TS2322:   The types returned by 'map(...)' are incompatible between these types.
+!!! error TS2322:     Type '{ [x: number]: U; c: U; length: U; toString: U; toLocaleString: U; pop: U; push: U; concat: U; join: U; reverse: U; shift: U; slice: U; sort: U; splice: U; unshift: U; indexOf: U; lastIndexOf: U; every: U; some: U; forEach: U; map: U; filter: U; reduce: U; reduceRight: U; } extends U[] ? { [x: number]: U; c: U; length: U; toString: U; toLocaleString: U; pop: U; push: U; concat: U; join: U; reverse: U; shift: U; slice: U; sort: U; splice: U; unshift: U; indexOf: U; lastIndexOf: U; every: U; some: U; forEach: U; map: U; filter: U; reduce: U; reduceRight: U; } : U[]' is not assignable to type 'U[]'.
+!!! error TS2322:       Type 'U[] | { [x: number]: U; c: U; length: U; toString: U; toLocaleString: U; pop: U; push: U; concat: U; join: U; reverse: U; shift: U; slice: U; sort: U; splice: U; unshift: U; indexOf: U; lastIndexOf: U; every: U; some: U; forEach: U; map: U; filter: U; reduce: U; reduceRight: U; }' is not assignable to type 'U[]'.
+!!! error TS2322:         Type '{ [x: number]: U; c: U; length: U; toString: U; toLocaleString: U; pop: U; push: U; concat: U; join: U; reverse: U; shift: U; slice: U; sort: U; splice: U; unshift: U; indexOf: U; lastIndexOf: U; every: U; some: U; forEach: U; map: U; filter: U; reduce: U; reduceRight: U; }' is not assignable to type 'U[]'.
+!!! error TS2322:           Types of property 'length' are incompatible.
+!!! error TS2322:             Type 'U' is not assignable to type 'number'.
     rra = crb; // OK, C<B> is assignable to ReadonlyArray<A>
+    ~~~
+!!! error TS2322: Type 'C<B>' is not assignable to type 'readonly A[]'.
+!!! error TS2322:   The types returned by 'map(...)' are incompatible between these types.
+!!! error TS2322:     Type '{ [x: number]: U; c: U; length: U; toString: U; toLocaleString: U; pop: U; push: U; concat: U; join: U; reverse: U; shift: U; slice: U; sort: U; splice: U; unshift: U; indexOf: U; lastIndexOf: U; every: U; some: U; forEach: U; map: U; filter: U; reduce: U; reduceRight: U; } extends U[] ? { [x: number]: U; c: U; length: U; toString: U; toLocaleString: U; pop: U; push: U; concat: U; join: U; reverse: U; shift: U; slice: U; sort: U; splice: U; unshift: U; indexOf: U; lastIndexOf: U; every: U; some: U; forEach: U; map: U; filter: U; reduce: U; reduceRight: U; } : U[]' is not assignable to type 'U[]'.
+!!! error TS2322:       Type 'U[] | { [x: number]: U; c: U; length: U; toString: U; toLocaleString: U; pop: U; push: U; concat: U; join: U; reverse: U; shift: U; slice: U; sort: U; splice: U; unshift: U; indexOf: U; lastIndexOf: U; every: U; some: U; forEach: U; map: U; filter: U; reduce: U; reduceRight: U; }' is not assignable to type 'U[]'.
+!!! error TS2322:         Type '{ [x: number]: U; c: U; length: U; toString: U; toLocaleString: U; pop: U; push: U; concat: U; join: U; reverse: U; shift: U; slice: U; sort: U; splice: U; unshift: U; indexOf: U; lastIndexOf: U; every: U; some: U; forEach: U; map: U; filter: U; reduce: U; reduceRight: U; }' is not assignable to type 'U[]'.
+!!! error TS2322:           Types of property 'length' are incompatible.
+!!! error TS2322:             Type 'U' is not assignable to type 'number'.
     rrb = crb;
+    ~~~
+!!! error TS2322: Type 'C<B>' is not assignable to type 'readonly B[]'.
+!!! error TS2322:   The types returned by 'map(...)' are incompatible between these types.
+!!! error TS2322:     Type '{ [x: number]: U; c: U; length: U; toString: U; toLocaleString: U; pop: U; push: U; concat: U; join: U; reverse: U; shift: U; slice: U; sort: U; splice: U; unshift: U; indexOf: U; lastIndexOf: U; every: U; some: U; forEach: U; map: U; filter: U; reduce: U; reduceRight: U; } extends U[] ? { [x: number]: U; c: U; length: U; toString: U; toLocaleString: U; pop: U; push: U; concat: U; join: U; reverse: U; shift: U; slice: U; sort: U; splice: U; unshift: U; indexOf: U; lastIndexOf: U; every: U; some: U; forEach: U; map: U; filter: U; reduce: U; reduceRight: U; } : U[]' is not assignable to type 'U[]'.
     rrb = cra; // error: 'A' is not assignable to 'B'
     ~~~
 !!! error TS2322: Type 'C<A>' is not assignable to type 'readonly B[]'.
diff --git a/tests/baselines/reference/bestChoiceType.errors.txt b/tests/baselines/reference/bestChoiceType.errors.txt
new file mode 100644
index 0000000000000..dd27c2cdfaeef
--- /dev/null
+++ b/tests/baselines/reference/bestChoiceType.errors.txt
@@ -0,0 +1,36 @@
+tests/cases/compiler/bestChoiceType.ts(3,23): error TS2349: This expression is not callable.
+  Each member of the union type '(<U>(callbackfn: (value: string, index: number, array: string[]) => U, thisArg?: any) => { [x: number]: U; index?: U | undefined; input?: U | undefined; length: U; toString: U; toLocaleString: U; pop: U; push: U; concat: U; join: U; reverse: U; shift: U; slice: U; sort: U; splice: U; unshift: U; indexOf: U; lastIndexOf: U; every: U; some: U; forEach: U; map: U; filter: U; reduce: U; reduceRight: U; } extends U[] ? { [x: number]: U; index?: U | undefined; input?: U | undefined; length: U; toString: U; toLocaleString: U; pop: U; push: U; concat: U; join: U; reverse: U; shift: U; slice: U; sort: U; splice: U; unshift: U; indexOf: U; lastIndexOf: U; every: U; some: U; forEach: U; map: U; filter: U; reduce: U; reduceRight: U; } : U[]) | (<U>(callbackfn: (value: never, index: number, array: never[]) => U, thisArg?: any) => U[])' has signatures, but none of those signatures are compatible with each other.
+tests/cases/compiler/bestChoiceType.ts(10,15): error TS2349: This expression is not callable.
+  Each member of the union type '(<U>(callbackfn: (value: string, index: number, array: string[]) => U, thisArg?: any) => { [x: number]: U; index?: U | undefined; input?: U | undefined; length: U; toString: U; toLocaleString: U; pop: U; push: U; concat: U; join: U; reverse: U; shift: U; slice: U; sort: U; splice: U; unshift: U; indexOf: U; lastIndexOf: U; every: U; some: U; forEach: U; map: U; filter: U; reduce: U; reduceRight: U; } extends U[] ? { [x: number]: U; index?: U | undefined; input?: U | undefined; length: U; toString: U; toLocaleString: U; pop: U; push: U; concat: U; join: U; reverse: U; shift: U; slice: U; sort: U; splice: U; unshift: U; indexOf: U; lastIndexOf: U; every: U; some: U; forEach: U; map: U; filter: U; reduce: U; reduceRight: U; } : U[]) | (<U>(callbackfn: (value: never, index: number, array: never[]) => U, thisArg?: any) => U[])' has signatures, but none of those signatures are compatible with each other.
+tests/cases/compiler/bestChoiceType.ts(16,15): error TS2349: This expression is not callable.
+  Each member of the union type '(<U>(callbackfn: (value: string, index: number, array: string[]) => U, thisArg?: any) => { [x: number]: U; index?: U | undefined; input?: U | undefined; length: U; toString: U; toLocaleString: U; pop: U; push: U; concat: U; join: U; reverse: U; shift: U; slice: U; sort: U; splice: U; unshift: U; indexOf: U; lastIndexOf: U; every: U; some: U; forEach: U; map: U; filter: U; reduce: U; reduceRight: U; } extends U[] ? { [x: number]: U; index?: U | undefined; input?: U | undefined; length: U; toString: U; toLocaleString: U; pop: U; push: U; concat: U; join: U; reverse: U; shift: U; slice: U; sort: U; splice: U; unshift: U; indexOf: U; lastIndexOf: U; every: U; some: U; forEach: U; map: U; filter: U; reduce: U; reduceRight: U; } : U[]) | (<U>(callbackfn: (value: never, index: number, array: never[]) => U, thisArg?: any) => U[])' has signatures, but none of those signatures are compatible with each other.
+
+
+==== tests/cases/compiler/bestChoiceType.ts (3 errors) ====
+    // Repro from #10041
+    
+    (''.match(/ /) || []).map(s => s.toLowerCase());
+                          ~~~
+!!! error TS2349: This expression is not callable.
+!!! error TS2349:   Each member of the union type '(<U>(callbackfn: (value: string, index: number, array: string[]) => U, thisArg?: any) => { [x: number]: U; index?: U | undefined; input?: U | undefined; length: U; toString: U; toLocaleString: U; pop: U; push: U; concat: U; join: U; reverse: U; shift: U; slice: U; sort: U; splice: U; unshift: U; indexOf: U; lastIndexOf: U; every: U; some: U; forEach: U; map: U; filter: U; reduce: U; reduceRight: U; } extends U[] ? { [x: number]: U; index?: U | undefined; input?: U | undefined; length: U; toString: U; toLocaleString: U; pop: U; push: U; concat: U; join: U; reverse: U; shift: U; slice: U; sort: U; splice: U; unshift: U; indexOf: U; lastIndexOf: U; every: U; some: U; forEach: U; map: U; filter: U; reduce: U; reduceRight: U; } : U[]) | (<U>(callbackfn: (value: never, index: number, array: never[]) => U, thisArg?: any) => U[])' has signatures, but none of those signatures are compatible with each other.
+    
+    // Similar cases
+    
+    function f1() {
+        let x = ''.match(/ /);
+        let y = x || [];
+        let z = y.map(s => s.toLowerCase());
+                  ~~~
+!!! error TS2349: This expression is not callable.
+!!! error TS2349:   Each member of the union type '(<U>(callbackfn: (value: string, index: number, array: string[]) => U, thisArg?: any) => { [x: number]: U; index?: U | undefined; input?: U | undefined; length: U; toString: U; toLocaleString: U; pop: U; push: U; concat: U; join: U; reverse: U; shift: U; slice: U; sort: U; splice: U; unshift: U; indexOf: U; lastIndexOf: U; every: U; some: U; forEach: U; map: U; filter: U; reduce: U; reduceRight: U; } extends U[] ? { [x: number]: U; index?: U | undefined; input?: U | undefined; length: U; toString: U; toLocaleString: U; pop: U; push: U; concat: U; join: U; reverse: U; shift: U; slice: U; sort: U; splice: U; unshift: U; indexOf: U; lastIndexOf: U; every: U; some: U; forEach: U; map: U; filter: U; reduce: U; reduceRight: U; } : U[]) | (<U>(callbackfn: (value: never, index: number, array: never[]) => U, thisArg?: any) => U[])' has signatures, but none of those signatures are compatible with each other.
+    }
+    
+    function f2() {
+        let x = ''.match(/ /);
+        let y = x ? x : [];
+        let z = y.map(s => s.toLowerCase());
+                  ~~~
+!!! error TS2349: This expression is not callable.
+!!! error TS2349:   Each member of the union type '(<U>(callbackfn: (value: string, index: number, array: string[]) => U, thisArg?: any) => { [x: number]: U; index?: U | undefined; input?: U | undefined; length: U; toString: U; toLocaleString: U; pop: U; push: U; concat: U; join: U; reverse: U; shift: U; slice: U; sort: U; splice: U; unshift: U; indexOf: U; lastIndexOf: U; every: U; some: U; forEach: U; map: U; filter: U; reduce: U; reduceRight: U; } extends U[] ? { [x: number]: U; index?: U | undefined; input?: U | undefined; length: U; toString: U; toLocaleString: U; pop: U; push: U; concat: U; join: U; reverse: U; shift: U; slice: U; sort: U; splice: U; unshift: U; indexOf: U; lastIndexOf: U; every: U; some: U; forEach: U; map: U; filter: U; reduce: U; reduceRight: U; } : U[]) | (<U>(callbackfn: (value: never, index: number, array: never[]) => U, thisArg?: any) => U[])' has signatures, but none of those signatures are compatible with each other.
+    }
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/bestChoiceType.symbols b/tests/baselines/reference/bestChoiceType.symbols
index c7732890347d0..0072356223368 100644
--- a/tests/baselines/reference/bestChoiceType.symbols
+++ b/tests/baselines/reference/bestChoiceType.symbols
@@ -2,14 +2,12 @@
 // Repro from #10041
 
 (''.match(/ /) || []).map(s => s.toLowerCase());
->(''.match(/ /) || []).map : Symbol(Array.map, Decl(lib.es5.d.ts, --, --))
+>(''.match(/ /) || []).map : Symbol(Array.map, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
 >''.match : Symbol(String.match, Decl(lib.es5.d.ts, --, --))
 >match : Symbol(String.match, Decl(lib.es5.d.ts, --, --))
->map : Symbol(Array.map, Decl(lib.es5.d.ts, --, --))
+>map : Symbol(Array.map, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
 >s : Symbol(s, Decl(bestChoiceType.ts, 2, 26))
->s.toLowerCase : Symbol(String.toLowerCase, Decl(lib.es5.d.ts, --, --))
 >s : Symbol(s, Decl(bestChoiceType.ts, 2, 26))
->toLowerCase : Symbol(String.toLowerCase, Decl(lib.es5.d.ts, --, --))
 
 // Similar cases
 
@@ -27,13 +25,11 @@ function f1() {
 
     let z = y.map(s => s.toLowerCase());
 >z : Symbol(z, Decl(bestChoiceType.ts, 9, 7))
->y.map : Symbol(Array.map, Decl(lib.es5.d.ts, --, --))
+>y.map : Symbol(Array.map, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
 >y : Symbol(y, Decl(bestChoiceType.ts, 8, 7))
->map : Symbol(Array.map, Decl(lib.es5.d.ts, --, --))
+>map : Symbol(Array.map, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
 >s : Symbol(s, Decl(bestChoiceType.ts, 9, 18))
->s.toLowerCase : Symbol(String.toLowerCase, Decl(lib.es5.d.ts, --, --))
 >s : Symbol(s, Decl(bestChoiceType.ts, 9, 18))
->toLowerCase : Symbol(String.toLowerCase, Decl(lib.es5.d.ts, --, --))
 }
 
 function f2() {
@@ -51,12 +47,10 @@ function f2() {
 
     let z = y.map(s => s.toLowerCase());
 >z : Symbol(z, Decl(bestChoiceType.ts, 15, 7))
->y.map : Symbol(Array.map, Decl(lib.es5.d.ts, --, --))
+>y.map : Symbol(Array.map, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
 >y : Symbol(y, Decl(bestChoiceType.ts, 14, 7))
->map : Symbol(Array.map, Decl(lib.es5.d.ts, --, --))
+>map : Symbol(Array.map, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
 >s : Symbol(s, Decl(bestChoiceType.ts, 15, 18))
->s.toLowerCase : Symbol(String.toLowerCase, Decl(lib.es5.d.ts, --, --))
 >s : Symbol(s, Decl(bestChoiceType.ts, 15, 18))
->toLowerCase : Symbol(String.toLowerCase, Decl(lib.es5.d.ts, --, --))
 }
 
diff --git a/tests/baselines/reference/bestChoiceType.types b/tests/baselines/reference/bestChoiceType.types
index 49997d1e273cc..771697a2e45e6 100644
--- a/tests/baselines/reference/bestChoiceType.types
+++ b/tests/baselines/reference/bestChoiceType.types
@@ -2,23 +2,23 @@
 // Repro from #10041
 
 (''.match(/ /) || []).map(s => s.toLowerCase());
->(''.match(/ /) || []).map(s => s.toLowerCase()) : string[]
->(''.match(/ /) || []).map : <U>(callbackfn: (value: string, index: number, array: string[]) => U, thisArg?: any) => U[]
->(''.match(/ /) || []) : RegExpMatchArray
->''.match(/ /) || [] : RegExpMatchArray
+>(''.match(/ /) || []).map(s => s.toLowerCase()) : any
+>(''.match(/ /) || []).map : (<U>(callbackfn: (value: string, index: number, array: string[]) => U, thisArg?: any) => { [x: number]: U; index?: U | undefined; input?: U | undefined; length: U; toString: U; toLocaleString: U; pop: U; push: U; concat: U; join: U; reverse: U; shift: U; slice: U; sort: U; splice: U; unshift: U; indexOf: U; lastIndexOf: U; every: U; some: U; forEach: U; map: U; filter: U; reduce: U; reduceRight: U; } extends U[] ? { [x: number]: U; index?: U | undefined; input?: U | undefined; length: U; toString: U; toLocaleString: U; pop: U; push: U; concat: U; join: U; reverse: U; shift: U; slice: U; sort: U; splice: U; unshift: U; indexOf: U; lastIndexOf: U; every: U; some: U; forEach: U; map: U; filter: U; reduce: U; reduceRight: U; } : U[]) | (<U>(callbackfn: (value: never, index: number, array: never[]) => U, thisArg?: any) => U[])
+>(''.match(/ /) || []) : RegExpMatchArray | never[]
+>''.match(/ /) || [] : RegExpMatchArray | never[]
 >''.match(/ /) : RegExpMatchArray | null
 >''.match : (regexp: string | RegExp) => RegExpMatchArray | null
 >'' : ""
 >match : (regexp: string | RegExp) => RegExpMatchArray | null
 >/ / : RegExp
 >[] : never[]
->map : <U>(callbackfn: (value: string, index: number, array: string[]) => U, thisArg?: any) => U[]
->s => s.toLowerCase() : (s: string) => string
->s : string
->s.toLowerCase() : string
->s.toLowerCase : () => string
->s : string
->toLowerCase : () => string
+>map : (<U>(callbackfn: (value: string, index: number, array: string[]) => U, thisArg?: any) => { [x: number]: U; index?: U | undefined; input?: U | undefined; length: U; toString: U; toLocaleString: U; pop: U; push: U; concat: U; join: U; reverse: U; shift: U; slice: U; sort: U; splice: U; unshift: U; indexOf: U; lastIndexOf: U; every: U; some: U; forEach: U; map: U; filter: U; reduce: U; reduceRight: U; } extends U[] ? { [x: number]: U; index?: U | undefined; input?: U | undefined; length: U; toString: U; toLocaleString: U; pop: U; push: U; concat: U; join: U; reverse: U; shift: U; slice: U; sort: U; splice: U; unshift: U; indexOf: U; lastIndexOf: U; every: U; some: U; forEach: U; map: U; filter: U; reduce: U; reduceRight: U; } : U[]) | (<U>(callbackfn: (value: never, index: number, array: never[]) => U, thisArg?: any) => U[])
+>s => s.toLowerCase() : (s: any) => any
+>s : any
+>s.toLowerCase() : any
+>s.toLowerCase : any
+>s : any
+>toLowerCase : any
 
 // Similar cases
 
@@ -34,23 +34,23 @@ function f1() {
 >/ / : RegExp
 
     let y = x || [];
->y : RegExpMatchArray
->x || [] : RegExpMatchArray
+>y : RegExpMatchArray | never[]
+>x || [] : RegExpMatchArray | never[]
 >x : RegExpMatchArray | null
 >[] : never[]
 
     let z = y.map(s => s.toLowerCase());
->z : string[]
->y.map(s => s.toLowerCase()) : string[]
->y.map : <U>(callbackfn: (value: string, index: number, array: string[]) => U, thisArg?: any) => U[]
->y : RegExpMatchArray
->map : <U>(callbackfn: (value: string, index: number, array: string[]) => U, thisArg?: any) => U[]
->s => s.toLowerCase() : (s: string) => string
->s : string
->s.toLowerCase() : string
->s.toLowerCase : () => string
->s : string
->toLowerCase : () => string
+>z : any
+>y.map(s => s.toLowerCase()) : any
+>y.map : (<U>(callbackfn: (value: string, index: number, array: string[]) => U, thisArg?: any) => { [x: number]: U; index?: U | undefined; input?: U | undefined; length: U; toString: U; toLocaleString: U; pop: U; push: U; concat: U; join: U; reverse: U; shift: U; slice: U; sort: U; splice: U; unshift: U; indexOf: U; lastIndexOf: U; every: U; some: U; forEach: U; map: U; filter: U; reduce: U; reduceRight: U; } extends U[] ? { [x: number]: U; index?: U | undefined; input?: U | undefined; length: U; toString: U; toLocaleString: U; pop: U; push: U; concat: U; join: U; reverse: U; shift: U; slice: U; sort: U; splice: U; unshift: U; indexOf: U; lastIndexOf: U; every: U; some: U; forEach: U; map: U; filter: U; reduce: U; reduceRight: U; } : U[]) | (<U>(callbackfn: (value: never, index: number, array: never[]) => U, thisArg?: any) => U[])
+>y : RegExpMatchArray | never[]
+>map : (<U>(callbackfn: (value: string, index: number, array: string[]) => U, thisArg?: any) => { [x: number]: U; index?: U | undefined; input?: U | undefined; length: U; toString: U; toLocaleString: U; pop: U; push: U; concat: U; join: U; reverse: U; shift: U; slice: U; sort: U; splice: U; unshift: U; indexOf: U; lastIndexOf: U; every: U; some: U; forEach: U; map: U; filter: U; reduce: U; reduceRight: U; } extends U[] ? { [x: number]: U; index?: U | undefined; input?: U | undefined; length: U; toString: U; toLocaleString: U; pop: U; push: U; concat: U; join: U; reverse: U; shift: U; slice: U; sort: U; splice: U; unshift: U; indexOf: U; lastIndexOf: U; every: U; some: U; forEach: U; map: U; filter: U; reduce: U; reduceRight: U; } : U[]) | (<U>(callbackfn: (value: never, index: number, array: never[]) => U, thisArg?: any) => U[])
+>s => s.toLowerCase() : (s: any) => any
+>s : any
+>s.toLowerCase() : any
+>s.toLowerCase : any
+>s : any
+>toLowerCase : any
 }
 
 function f2() {
@@ -65,23 +65,23 @@ function f2() {
 >/ / : RegExp
 
     let y = x ? x : [];
->y : RegExpMatchArray
->x ? x : [] : RegExpMatchArray
+>y : RegExpMatchArray | never[]
+>x ? x : [] : RegExpMatchArray | never[]
 >x : RegExpMatchArray | null
 >x : RegExpMatchArray
 >[] : never[]
 
     let z = y.map(s => s.toLowerCase());
->z : string[]
->y.map(s => s.toLowerCase()) : string[]
->y.map : <U>(callbackfn: (value: string, index: number, array: string[]) => U, thisArg?: any) => U[]
->y : RegExpMatchArray
->map : <U>(callbackfn: (value: string, index: number, array: string[]) => U, thisArg?: any) => U[]
->s => s.toLowerCase() : (s: string) => string
->s : string
->s.toLowerCase() : string
->s.toLowerCase : () => string
->s : string
->toLowerCase : () => string
+>z : any
+>y.map(s => s.toLowerCase()) : any
+>y.map : (<U>(callbackfn: (value: string, index: number, array: string[]) => U, thisArg?: any) => { [x: number]: U; index?: U | undefined; input?: U | undefined; length: U; toString: U; toLocaleString: U; pop: U; push: U; concat: U; join: U; reverse: U; shift: U; slice: U; sort: U; splice: U; unshift: U; indexOf: U; lastIndexOf: U; every: U; some: U; forEach: U; map: U; filter: U; reduce: U; reduceRight: U; } extends U[] ? { [x: number]: U; index?: U | undefined; input?: U | undefined; length: U; toString: U; toLocaleString: U; pop: U; push: U; concat: U; join: U; reverse: U; shift: U; slice: U; sort: U; splice: U; unshift: U; indexOf: U; lastIndexOf: U; every: U; some: U; forEach: U; map: U; filter: U; reduce: U; reduceRight: U; } : U[]) | (<U>(callbackfn: (value: never, index: number, array: never[]) => U, thisArg?: any) => U[])
+>y : RegExpMatchArray | never[]
+>map : (<U>(callbackfn: (value: string, index: number, array: string[]) => U, thisArg?: any) => { [x: number]: U; index?: U | undefined; input?: U | undefined; length: U; toString: U; toLocaleString: U; pop: U; push: U; concat: U; join: U; reverse: U; shift: U; slice: U; sort: U; splice: U; unshift: U; indexOf: U; lastIndexOf: U; every: U; some: U; forEach: U; map: U; filter: U; reduce: U; reduceRight: U; } extends U[] ? { [x: number]: U; index?: U | undefined; input?: U | undefined; length: U; toString: U; toLocaleString: U; pop: U; push: U; concat: U; join: U; reverse: U; shift: U; slice: U; sort: U; splice: U; unshift: U; indexOf: U; lastIndexOf: U; every: U; some: U; forEach: U; map: U; filter: U; reduce: U; reduceRight: U; } : U[]) | (<U>(callbackfn: (value: never, index: number, array: never[]) => U, thisArg?: any) => U[])
+>s => s.toLowerCase() : (s: any) => any
+>s : any
+>s.toLowerCase() : any
+>s.toLowerCase : any
+>s : any
+>toLowerCase : any
 }
 
diff --git a/tests/baselines/reference/contextuallyTypedIife.types b/tests/baselines/reference/contextuallyTypedIife.types
index 4e6f9f71c923e..9c9579ef14285 100644
--- a/tests/baselines/reference/contextuallyTypedIife.types
+++ b/tests/baselines/reference/contextuallyTypedIife.types
@@ -151,18 +151,18 @@
 >0 : 0
 
 ((first, ...rest) => first ? [] : rest.map(n => n > 0))(8,9,10);
->((first, ...rest) => first ? [] : rest.map(n => n > 0))(8,9,10) : boolean[]
->((first, ...rest) => first ? [] : rest.map(n => n > 0)) : (first: number, rest_0: number, rest_1: number) => boolean[]
->(first, ...rest) => first ? [] : rest.map(n => n > 0) : (first: number, rest_0: number, rest_1: number) => boolean[]
+>((first, ...rest) => first ? [] : rest.map(n => n > 0))(8,9,10) : any[] | [boolean, boolean]
+>((first, ...rest) => first ? [] : rest.map(n => n > 0)) : (first: number, rest_0: number, rest_1: number) => any[] | [boolean, boolean]
+>(first, ...rest) => first ? [] : rest.map(n => n > 0) : (first: number, rest_0: number, rest_1: number) => any[] | [boolean, boolean]
 >first : number
 >rest : [number, number]
->first ? [] : rest.map(n => n > 0) : boolean[]
+>first ? [] : rest.map(n => n > 0) : undefined[] | [boolean, boolean]
 >first : number
 >[] : undefined[]
->rest.map(n => n > 0) : boolean[]
->rest.map : <U>(callbackfn: (value: number, index: number, array: number[]) => U, thisArg?: any) => U[]
+>rest.map(n => n > 0) : [boolean, boolean]
+>rest.map : <U>(callbackfn: (value: number, index: number, array: number[]) => U, thisArg?: any) => [U, U]
 >rest : [number, number]
->map : <U>(callbackfn: (value: number, index: number, array: number[]) => U, thisArg?: any) => U[]
+>map : <U>(callbackfn: (value: number, index: number, array: number[]) => U, thisArg?: any) => [U, U]
 >n => n > 0 : (n: number) => boolean
 >n : number
 >n > 0 : boolean
diff --git a/tests/baselines/reference/contextuallyTypedIifeStrict.types b/tests/baselines/reference/contextuallyTypedIifeStrict.types
index 18ad0a1241f73..a81d425e49823 100644
--- a/tests/baselines/reference/contextuallyTypedIifeStrict.types
+++ b/tests/baselines/reference/contextuallyTypedIifeStrict.types
@@ -151,18 +151,18 @@
 >0 : 0
 
 ((first, ...rest) => first ? [] : rest.map(n => n > 0))(8,9,10);
->((first, ...rest) => first ? [] : rest.map(n => n > 0))(8,9,10) : boolean[]
->((first, ...rest) => first ? [] : rest.map(n => n > 0)) : (first: number, rest_0: number, rest_1: number) => boolean[]
->(first, ...rest) => first ? [] : rest.map(n => n > 0) : (first: number, rest_0: number, rest_1: number) => boolean[]
+>((first, ...rest) => first ? [] : rest.map(n => n > 0))(8,9,10) : never[] | [boolean, boolean]
+>((first, ...rest) => first ? [] : rest.map(n => n > 0)) : (first: number, rest_0: number, rest_1: number) => never[] | [boolean, boolean]
+>(first, ...rest) => first ? [] : rest.map(n => n > 0) : (first: number, rest_0: number, rest_1: number) => never[] | [boolean, boolean]
 >first : number
 >rest : [number, number]
->first ? [] : rest.map(n => n > 0) : boolean[]
+>first ? [] : rest.map(n => n > 0) : never[] | [boolean, boolean]
 >first : number
 >[] : never[]
->rest.map(n => n > 0) : boolean[]
->rest.map : <U>(callbackfn: (value: number, index: number, array: number[]) => U, thisArg?: any) => U[]
+>rest.map(n => n > 0) : [boolean, boolean]
+>rest.map : <U>(callbackfn: (value: number, index: number, array: number[]) => U, thisArg?: any) => [U, U]
 >rest : [number, number]
->map : <U>(callbackfn: (value: number, index: number, array: number[]) => U, thisArg?: any) => U[]
+>map : <U>(callbackfn: (value: number, index: number, array: number[]) => U, thisArg?: any) => [U, U]
 >n => n > 0 : (n: number) => boolean
 >n : number
 >n > 0 : boolean
diff --git a/tests/baselines/reference/destructuringArrayBindingPatternAndAssignment2.errors.txt b/tests/baselines/reference/destructuringArrayBindingPatternAndAssignment2.errors.txt
index dd01ac9651928..85a07b28e3de1 100644
--- a/tests/baselines/reference/destructuringArrayBindingPatternAndAssignment2.errors.txt
+++ b/tests/baselines/reference/destructuringArrayBindingPatternAndAssignment2.errors.txt
@@ -4,12 +4,13 @@ tests/cases/conformance/es6/destructuring/destructuringArrayBindingPatternAndAss
 tests/cases/conformance/es6/destructuring/destructuringArrayBindingPatternAndAssignment2.ts(3,12): error TS2493: Tuple type '[]' of length '0' has no element at index '1'.
 tests/cases/conformance/es6/destructuring/destructuringArrayBindingPatternAndAssignment2.ts(4,5): error TS2461: Type 'undefined' is not an array type.
 tests/cases/conformance/es6/destructuring/destructuringArrayBindingPatternAndAssignment2.ts(9,51): error TS2322: Type 'number' is not assignable to type 'boolean'.
+tests/cases/conformance/es6/destructuring/destructuringArrayBindingPatternAndAssignment2.ts(17,5): error TS2461: Type 'J' is not an array type.
 tests/cases/conformance/es6/destructuring/destructuringArrayBindingPatternAndAssignment2.ts(22,5): error TS2739: Type 'number[]' is missing the following properties from type '[number, number]': 0, 1
 tests/cases/conformance/es6/destructuring/destructuringArrayBindingPatternAndAssignment2.ts(23,5): error TS2739: Type 'number[]' is missing the following properties from type '[string, string]': 0, 1
 tests/cases/conformance/es6/destructuring/destructuringArrayBindingPatternAndAssignment2.ts(34,5): error TS2461: Type 'F' is not an array type.
 
 
-==== tests/cases/conformance/es6/destructuring/destructuringArrayBindingPatternAndAssignment2.ts (9 errors) ====
+==== tests/cases/conformance/es6/destructuring/destructuringArrayBindingPatternAndAssignment2.ts (10 errors) ====
     // V is an array assignment pattern, S is the type Any or an array-like type (section 3.3.2), and, for each assignment element E in V,
     //      S is the type Any, or
     var [[a0], [[a1]]] = []         // Error
@@ -39,6 +40,8 @@ tests/cases/conformance/es6/destructuring/destructuringArrayBindingPatternAndAss
         return <[number, number, number]>[1, 2, 3];
     }
     var [b3 = "string", b4, b5] = bar();  // Error
+        ~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2461: Type 'J' is not an array type.
     
     // V is an array assignment pattern, S is the type Any or an array-like type (section 3.3.2), and, for each assignment element E in V,
     //      S is not a tuple- like type and the numeric index signature type of S is assignable to the target given in E.
diff --git a/tests/baselines/reference/destructuringArrayBindingPatternAndAssignment2.types b/tests/baselines/reference/destructuringArrayBindingPatternAndAssignment2.types
index 86723735bb544..411a423f53274 100644
--- a/tests/baselines/reference/destructuringArrayBindingPatternAndAssignment2.types
+++ b/tests/baselines/reference/destructuringArrayBindingPatternAndAssignment2.types
@@ -39,10 +39,10 @@ function bar(): J {
 >3 : 3
 }
 var [b3 = "string", b4, b5] = bar();  // Error
->b3 : string | Number
+>b3 : any
 >"string" : "string"
->b4 : Number
->b5 : number
+>b4 : any
+>b5 : any
 >bar() : J
 >bar : () => J
 
diff --git a/tests/baselines/reference/genericRestParameters3.errors.txt b/tests/baselines/reference/genericRestParameters3.errors.txt
index 9e3e9d97de42d..d83197e8c394a 100644
--- a/tests/baselines/reference/genericRestParameters3.errors.txt
+++ b/tests/baselines/reference/genericRestParameters3.errors.txt
@@ -22,6 +22,7 @@ tests/cases/conformance/types/rest/genericRestParameters3.ts(37,21): error TS234
     Property '0' is missing in type 'CoolArray<any>' but required in type '[(...args: any[]) => void]'.
 tests/cases/conformance/types/rest/genericRestParameters3.ts(44,32): error TS2345: Argument of type '[10, 20]' is not assignable to parameter of type 'CoolArray<number>'.
   Property 'hello' is missing in type '[10, 20]' but required in type 'CoolArray<number>'.
+tests/cases/conformance/types/rest/genericRestParameters3.ts(46,25): error TS2370: A rest parameter must be of an array type.
 tests/cases/conformance/types/rest/genericRestParameters3.ts(49,1): error TS2345: Argument of type '[]' is not assignable to parameter of type 'CoolArray<unknown>'.
   Property 'hello' is missing in type '[]' but required in type 'CoolArray<unknown>'.
 tests/cases/conformance/types/rest/genericRestParameters3.ts(50,5): error TS2345: Argument of type '[number]' is not assignable to parameter of type 'CoolArray<unknown>'.
@@ -30,11 +31,12 @@ tests/cases/conformance/types/rest/genericRestParameters3.ts(51,5): error TS2345
   Property 'hello' is missing in type '[number, number]' but required in type 'CoolArray<unknown>'.
 tests/cases/conformance/types/rest/genericRestParameters3.ts(52,5): error TS2345: Argument of type 'number[]' is not assignable to parameter of type 'CoolArray<number>'.
   Property 'hello' is missing in type 'number[]' but required in type 'CoolArray<number>'.
+tests/cases/conformance/types/rest/genericRestParameters3.ts(52,8): error TS2461: Type 'CoolArray<number>' is not an array type.
 tests/cases/conformance/types/rest/genericRestParameters3.ts(59,5): error TS2345: Argument of type '["what"]' is not assignable to parameter of type '[] | [number, string]'.
   Property '1' is missing in type '["what"]' but required in type '[number, string]'.
 
 
-==== tests/cases/conformance/types/rest/genericRestParameters3.ts (15 errors) ====
+==== tests/cases/conformance/types/rest/genericRestParameters3.ts (17 errors) ====
     declare let f1: (x: string, ...args: [string] | [number, boolean]) => void;
     declare let f2: (x: string, y: string) => void;
     declare let f3: (x: string, y: number, z: boolean) => void;
@@ -117,6 +119,8 @@ tests/cases/conformance/types/rest/genericRestParameters3.ts(59,5): error TS2345
 !!! related TS2728 tests/cases/conformance/types/rest/genericRestParameters3.ts:30:5: 'hello' is declared here.
     
     declare function baz<T>(...args: CoolArray<T>): void;
+                            ~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2370: A rest parameter must be of an array type.
     declare const ca: CoolArray<number>;
     
     baz();       // Error
@@ -139,6 +143,8 @@ tests/cases/conformance/types/rest/genericRestParameters3.ts(59,5): error TS2345
 !!! error TS2345: Argument of type 'number[]' is not assignable to parameter of type 'CoolArray<number>'.
 !!! error TS2345:   Property 'hello' is missing in type 'number[]' but required in type 'CoolArray<number>'.
 !!! related TS2728 tests/cases/conformance/types/rest/genericRestParameters3.ts:30:5: 'hello' is declared here.
+           ~~
+!!! error TS2461: Type 'CoolArray<number>' is not an array type.
     
     // Repro from #26491
     
diff --git a/tests/baselines/reference/genericRestParameters3.types b/tests/baselines/reference/genericRestParameters3.types
index a0d90a308d7b4..c73abe74c531f 100644
--- a/tests/baselines/reference/genericRestParameters3.types
+++ b/tests/baselines/reference/genericRestParameters3.types
@@ -186,7 +186,7 @@ baz(1, 2);   // Error
 baz(...ca);  // Error
 >baz(...ca) : any
 >baz : <T>(...args: CoolArray<T>) => void
->...ca : number
+>...ca : any
 >ca : CoolArray<number>
 
 // Repro from #26491
diff --git a/tests/baselines/reference/implementArrayInterface.errors.txt b/tests/baselines/reference/implementArrayInterface.errors.txt
new file mode 100644
index 0000000000000..773bb39d61305
--- /dev/null
+++ b/tests/baselines/reference/implementArrayInterface.errors.txt
@@ -0,0 +1,43 @@
+tests/cases/compiler/implementArrayInterface.ts(22,5): error TS2416: Property 'map' in type 'MyArray<T>' is not assignable to the same property in base type 'T[]'.
+  Type '<U>(callbackfn: (value: T, index: number, array: T[]) => U, thisArg?: any) => U[]' is not assignable to type '<U>(callbackfn: (value: T, index: number, array: T[]) => U, thisArg?: any) => { -readonly [P in keyof this]: U; } extends U[] ? { -readonly [P in keyof this]: U; } : U[]'.
+    Type 'U[]' is not assignable to type '{ -readonly [P in keyof this]: U; } extends U[] ? { -readonly [P in keyof this]: U; } : U[]'.
+
+
+==== tests/cases/compiler/implementArrayInterface.ts (1 errors) ====
+    declare class MyArray<T> implements Array<T> {
+        toString(): string;
+        toLocaleString(): string;
+        concat<U extends T[]>(...items: U[]): T[];
+        concat(...items: T[]): T[];
+        join(separator?: string): string;
+        pop(): T;
+        push(...items: T[]): number;
+        reverse(): T[];
+        shift(): T;
+        slice(start?: number, end?: number): T[];
+        sort(compareFn?: (a: T, b: T) => number): this;
+        splice(start: number): T[];
+        splice(start: number, deleteCount: number, ...items: T[]): T[];
+        unshift(...items: T[]): number;
+    
+        indexOf(searchElement: T, fromIndex?: number): number;
+        lastIndexOf(searchElement: T, fromIndex?: number): number;
+        every(callbackfn: (value: T, index: number, array: T[]) => boolean, thisArg?: any): boolean;
+        some(callbackfn: (value: T, index: number, array: T[]) => boolean, thisArg?: any): boolean;
+        forEach(callbackfn: (value: T, index: number, array: T[]) => void, thisArg?: any): void;
+        map<U>(callbackfn: (value: T, index: number, array: T[]) => U, thisArg?: any): U[];
+        ~~~
+!!! error TS2416: Property 'map' in type 'MyArray<T>' is not assignable to the same property in base type 'T[]'.
+!!! error TS2416:   Type '<U>(callbackfn: (value: T, index: number, array: T[]) => U, thisArg?: any) => U[]' is not assignable to type '<U>(callbackfn: (value: T, index: number, array: T[]) => U, thisArg?: any) => { -readonly [P in keyof this]: U; } extends U[] ? { -readonly [P in keyof this]: U; } : U[]'.
+!!! error TS2416:     Type 'U[]' is not assignable to type '{ -readonly [P in keyof this]: U; } extends U[] ? { -readonly [P in keyof this]: U; } : U[]'.
+        filter(callbackfn: (value: T, index: number, array: T[]) => boolean, thisArg?: any): T[];
+        reduce(callbackfn: (previousValue: T, currentValue: T, currentIndex: number, array: T[]) => T, initialValue?: T): T;
+        reduce<U>(callbackfn: (previousValue: U, currentValue: T, currentIndex: number, array: T[]) => U, initialValue: U): U;
+        reduceRight(callbackfn: (previousValue: T, currentValue: T, currentIndex: number, array: T[]) => T, initialValue?: T): T;
+        reduceRight<U>(callbackfn: (previousValue: U, currentValue: T, currentIndex: number, array: T[]) => U, initialValue: U): U;
+    
+        length: number;
+    
+        [n: number]: T;
+    }
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/initializedDestructuringAssignmentTypes.errors.txt b/tests/baselines/reference/initializedDestructuringAssignmentTypes.errors.txt
index 9a8cb12b45b61..f490cbc1432d8 100644
--- a/tests/baselines/reference/initializedDestructuringAssignmentTypes.errors.txt
+++ b/tests/baselines/reference/initializedDestructuringAssignmentTypes.errors.txt
@@ -1,9 +1,9 @@
-tests/cases/compiler/initializedDestructuringAssignmentTypes.ts(3,3): error TS2339: Property 'toFixed' does not exist on type 'string'.
+tests/cases/compiler/initializedDestructuringAssignmentTypes.ts(1,7): error TS2461: Type 'RegExpMatchArray | undefined[]' is not an array type.
 
 
 ==== tests/cases/compiler/initializedDestructuringAssignmentTypes.ts (1 errors) ====
     const [, a = ''] = ''.match('') || [];
+          ~~~~~~~~~~
+!!! error TS2461: Type 'RegExpMatchArray | undefined[]' is not an array type.
     
-    a.toFixed()
-      ~~~~~~~
-!!! error TS2339: Property 'toFixed' does not exist on type 'string'.
\ No newline at end of file
+    a.toFixed()
\ No newline at end of file
diff --git a/tests/baselines/reference/initializedDestructuringAssignmentTypes.types b/tests/baselines/reference/initializedDestructuringAssignmentTypes.types
index 333fc5d92ccd8..0b7dde7c11400 100644
--- a/tests/baselines/reference/initializedDestructuringAssignmentTypes.types
+++ b/tests/baselines/reference/initializedDestructuringAssignmentTypes.types
@@ -1,9 +1,9 @@
 === tests/cases/compiler/initializedDestructuringAssignmentTypes.ts ===
 const [, a = ''] = ''.match('') || [];
 > : undefined
->a : string
+>a : any
 >'' : ""
->''.match('') || [] : RegExpMatchArray
+>''.match('') || [] : RegExpMatchArray | undefined[]
 >''.match('') : RegExpMatchArray
 >''.match : (regexp: string | RegExp) => RegExpMatchArray
 >'' : ""
@@ -14,6 +14,6 @@ const [, a = ''] = ''.match('') || [];
 a.toFixed()
 >a.toFixed() : any
 >a.toFixed : any
->a : string
+>a : any
 >toFixed : any
 
diff --git a/tests/baselines/reference/mapOnTupleTypes01.js b/tests/baselines/reference/mapOnTupleTypes01.js
index 3298190fdee57..d1d5f8cc1a5f4 100644
--- a/tests/baselines/reference/mapOnTupleTypes01.js
+++ b/tests/baselines/reference/mapOnTupleTypes01.js
@@ -71,11 +71,11 @@ exports.h = numNumNumNumNum.map(function (n) { return n * n; });
 
 //// [mapOnTupleTypes01.d.ts]
 export declare let mapOnLooseArrayLiteral: number[];
-export declare let a: number[];
-export declare let b: number[];
-export declare let c: number[];
-export declare let d: (string | number)[];
-export declare let e: number[];
-export declare let f: number[];
-export declare let g: number[];
-export declare let h: number[];
+export declare let a: [number];
+export declare let b: [number, number];
+export declare let c: [number, number];
+export declare let d: [string | number, string | number];
+export declare let e: [number, number, number];
+export declare let f: [number, number, number, number];
+export declare let g: [number, number, number, number, number];
+export declare let h: [number, number, number, number, number];
diff --git a/tests/baselines/reference/mapOnTupleTypes01.types b/tests/baselines/reference/mapOnTupleTypes01.types
index adb8a2e191c26..4c9dc122d7e26 100644
--- a/tests/baselines/reference/mapOnTupleTypes01.types
+++ b/tests/baselines/reference/mapOnTupleTypes01.types
@@ -23,11 +23,11 @@ let numTuple: [number] = [1];
 >1 : 1
 
 export let a = numTuple.map(x => x * x);
->a : number[]
->numTuple.map(x => x * x) : number[]
->numTuple.map : <U>(callbackfn: (value: number, index: number, array: number[]) => U, thisArg?: any) => U[]
+>a : [number]
+>numTuple.map(x => x * x) : [number]
+>numTuple.map : <U>(callbackfn: (value: number, index: number, array: number[]) => U, thisArg?: any) => [U]
 >numTuple : [number]
->map : <U>(callbackfn: (value: number, index: number, array: number[]) => U, thisArg?: any) => U[]
+>map : <U>(callbackfn: (value: number, index: number, array: number[]) => U, thisArg?: any) => [U]
 >x => x * x : (x: number) => number
 >x : number
 >x * x : number
@@ -55,11 +55,11 @@ let numStr: [number, string] = [    100, "hello"];
 >"hello" : "hello"
 
 export let b = numNum.map(n => n * n);
->b : number[]
->numNum.map(n => n * n) : number[]
->numNum.map : <U>(callbackfn: (value: number, index: number, array: number[]) => U, thisArg?: any) => U[]
+>b : [number, number]
+>numNum.map(n => n * n) : [number, number]
+>numNum.map : <U>(callbackfn: (value: number, index: number, array: number[]) => U, thisArg?: any) => [U, U]
 >numNum : [number, number]
->map : <U>(callbackfn: (value: number, index: number, array: number[]) => U, thisArg?: any) => U[]
+>map : <U>(callbackfn: (value: number, index: number, array: number[]) => U, thisArg?: any) => [U, U]
 >n => n * n : (n: number) => number
 >n : number
 >n * n : number
@@ -67,11 +67,11 @@ export let b = numNum.map(n => n * n);
 >n : number
 
 export let c = strStr.map(s => s.charCodeAt(0));
->c : number[]
->strStr.map(s => s.charCodeAt(0)) : number[]
->strStr.map : <U>(callbackfn: (value: string, index: number, array: string[]) => U, thisArg?: any) => U[]
+>c : [number, number]
+>strStr.map(s => s.charCodeAt(0)) : [number, number]
+>strStr.map : <U>(callbackfn: (value: string, index: number, array: string[]) => U, thisArg?: any) => [U, U]
 >strStr : [string, string]
->map : <U>(callbackfn: (value: string, index: number, array: string[]) => U, thisArg?: any) => U[]
+>map : <U>(callbackfn: (value: string, index: number, array: string[]) => U, thisArg?: any) => [U, U]
 >s => s.charCodeAt(0) : (s: string) => number
 >s : string
 >s.charCodeAt(0) : number
@@ -81,11 +81,11 @@ export let c = strStr.map(s => s.charCodeAt(0));
 >0 : 0
 
 export let d = numStr.map(x => x);
->d : (string | number)[]
->numStr.map(x => x) : (string | number)[]
->numStr.map : <U>(callbackfn: (value: string | number, index: number, array: (string | number)[]) => U, thisArg?: any) => U[]
+>d : [string | number, string | number]
+>numStr.map(x => x) : [string | number, string | number]
+>numStr.map : <U>(callbackfn: (value: string | number, index: number, array: (string | number)[]) => U, thisArg?: any) => [U, U]
 >numStr : [number, string]
->map : <U>(callbackfn: (value: string | number, index: number, array: (string | number)[]) => U, thisArg?: any) => U[]
+>map : <U>(callbackfn: (value: string | number, index: number, array: (string | number)[]) => U, thisArg?: any) => [U, U]
 >x => x : (x: string | number) => string | number
 >x : string | number
 >x : string | number
@@ -100,11 +100,11 @@ let numNumNum: [number, number, number] = [1, 2, 3];
 >3 : 3
 
 export let e = numNumNum.map(n => n * n);
->e : number[]
->numNumNum.map(n => n * n) : number[]
->numNumNum.map : <U>(callbackfn: (value: number, index: number, array: number[]) => U, thisArg?: any) => U[]
+>e : [number, number, number]
+>numNumNum.map(n => n * n) : [number, number, number]
+>numNumNum.map : <U>(callbackfn: (value: number, index: number, array: number[]) => U, thisArg?: any) => [U, U, U]
 >numNumNum : [number, number, number]
->map : <U>(callbackfn: (value: number, index: number, array: number[]) => U, thisArg?: any) => U[]
+>map : <U>(callbackfn: (value: number, index: number, array: number[]) => U, thisArg?: any) => [U, U, U]
 >n => n * n : (n: number) => number
 >n : number
 >n * n : number
@@ -122,11 +122,11 @@ let numNumNumNum: [number, number, number, number] = [1, 2, 3, 4];
 >4 : 4
 
 export let f = numNumNumNum.map(n => n * n);
->f : number[]
->numNumNumNum.map(n => n * n) : number[]
->numNumNumNum.map : <U>(callbackfn: (value: number, index: number, array: number[]) => U, thisArg?: any) => U[]
+>f : [number, number, number, number]
+>numNumNumNum.map(n => n * n) : [number, number, number, number]
+>numNumNumNum.map : <U>(callbackfn: (value: number, index: number, array: number[]) => U, thisArg?: any) => [U, U, U, U]
 >numNumNumNum : [number, number, number, number]
->map : <U>(callbackfn: (value: number, index: number, array: number[]) => U, thisArg?: any) => U[]
+>map : <U>(callbackfn: (value: number, index: number, array: number[]) => U, thisArg?: any) => [U, U, U, U]
 >n => n * n : (n: number) => number
 >n : number
 >n * n : number
@@ -145,11 +145,11 @@ let numNumNumNumNum: [number, number, number, number, number] = [1, 2, 3, 4, 5];
 >5 : 5
 
 export let g = numNumNumNumNum.map(n => n * n);
->g : number[]
->numNumNumNumNum.map(n => n * n) : number[]
->numNumNumNumNum.map : <U>(callbackfn: (value: number, index: number, array: number[]) => U, thisArg?: any) => U[]
+>g : [number, number, number, number, number]
+>numNumNumNumNum.map(n => n * n) : [number, number, number, number, number]
+>numNumNumNumNum.map : <U>(callbackfn: (value: number, index: number, array: number[]) => U, thisArg?: any) => [U, U, U, U, U]
 >numNumNumNumNum : [number, number, number, number, number]
->map : <U>(callbackfn: (value: number, index: number, array: number[]) => U, thisArg?: any) => U[]
+>map : <U>(callbackfn: (value: number, index: number, array: number[]) => U, thisArg?: any) => [U, U, U, U, U]
 >n => n * n : (n: number) => number
 >n : number
 >n * n : number
@@ -170,11 +170,11 @@ let numNumNumNumNumNum: [number, number, number, number, number, number] = [1, 2
 >6 : 6
 
 export let h = numNumNumNumNum.map(n => n * n);
->h : number[]
->numNumNumNumNum.map(n => n * n) : number[]
->numNumNumNumNum.map : <U>(callbackfn: (value: number, index: number, array: number[]) => U, thisArg?: any) => U[]
+>h : [number, number, number, number, number]
+>numNumNumNumNum.map(n => n * n) : [number, number, number, number, number]
+>numNumNumNumNum.map : <U>(callbackfn: (value: number, index: number, array: number[]) => U, thisArg?: any) => [U, U, U, U, U]
 >numNumNumNumNum : [number, number, number, number, number]
->map : <U>(callbackfn: (value: number, index: number, array: number[]) => U, thisArg?: any) => U[]
+>map : <U>(callbackfn: (value: number, index: number, array: number[]) => U, thisArg?: any) => [U, U, U, U, U]
 >n => n * n : (n: number) => number
 >n : number
 >n * n : number
diff --git a/tests/baselines/reference/mapOnTupleTypes02.js b/tests/baselines/reference/mapOnTupleTypes02.js
index 8e0a8720a18cc..2fd4daab16bf5 100644
--- a/tests/baselines/reference/mapOnTupleTypes02.js
+++ b/tests/baselines/reference/mapOnTupleTypes02.js
@@ -16,4 +16,4 @@ exports.increment = increment;
 
 //// [mapOnTupleTypes02.d.ts]
 export declare type Point = [number, number];
-export declare function increment(point: Point): number[];
+export declare function increment(point: Point): [number, number];
diff --git a/tests/baselines/reference/mapOnTupleTypes02.types b/tests/baselines/reference/mapOnTupleTypes02.types
index 3f443a735cbe3..d503f7c2825af 100644
--- a/tests/baselines/reference/mapOnTupleTypes02.types
+++ b/tests/baselines/reference/mapOnTupleTypes02.types
@@ -3,14 +3,14 @@ export type Point = [number, number];
 >Point : Point
 
 export function increment(point: Point) {
->increment : (point: Point) => number[]
+>increment : (point: Point) => [number, number]
 >point : Point
 
   return point.map(d => d + 1);
->point.map(d => d + 1) : number[]
->point.map : <U>(callbackfn: (value: number, index: number, array: number[]) => U, thisArg?: any) => U[]
+>point.map(d => d + 1) : [number, number]
+>point.map : <U>(callbackfn: (value: number, index: number, array: number[]) => U, thisArg?: any) => [U, U]
 >point : Point
->map : <U>(callbackfn: (value: number, index: number, array: number[]) => U, thisArg?: any) => U[]
+>map : <U>(callbackfn: (value: number, index: number, array: number[]) => U, thisArg?: any) => [U, U]
 >d => d + 1 : (d: number) => number
 >d : number
 >d + 1 : number
diff --git a/tests/baselines/reference/restParameterWithBindingPattern3.types b/tests/baselines/reference/restParameterWithBindingPattern3.types
index b98f0cdd367d7..530b5806994d1 100644
--- a/tests/baselines/reference/restParameterWithBindingPattern3.types
+++ b/tests/baselines/reference/restParameterWithBindingPattern3.types
@@ -31,5 +31,5 @@ function e(...{0: a = 1, 1: b = true, ...rest: rest}: [boolean, string, number])
 >b : string
 >true : true
 >rest : any
->rest : { [n: number]: string | number | boolean; 0: boolean; 1: string; 2: number; length: 3; toString(): string; toLocaleString(): string; pop(): string | number | boolean; push(...items: (string | number | boolean)[]): number; concat(...items: ConcatArray<string | number | boolean>[]): (string | number | boolean)[]; concat(...items: (string | number | boolean | ConcatArray<string | number | boolean>)[]): (string | number | boolean)[]; join(separator?: string): string; reverse(): (string | number | boolean)[]; shift(): string | number | boolean; slice(start?: number, end?: number): (string | number | boolean)[]; sort(compareFn?: (a: string | number | boolean, b: string | number | boolean) => number): [boolean, string, number]; splice(start: number, deleteCount?: number): (string | number | boolean)[]; splice(start: number, deleteCount: number, ...items: (string | number | boolean)[]): (string | number | boolean)[]; unshift(...items: (string | number | boolean)[]): number; indexOf(searchElement: string | number | boolean, fromIndex?: number): number; lastIndexOf(searchElement: string | number | boolean, fromIndex?: number): number; every(callbackfn: (value: string | number | boolean, index: number, array: (string | number | boolean)[]) => unknown, thisArg?: any): boolean; some(callbackfn: (value: string | number | boolean, index: number, array: (string | number | boolean)[]) => unknown, thisArg?: any): boolean; forEach(callbackfn: (value: string | number | boolean, index: number, array: (string | number | boolean)[]) => void, thisArg?: any): void; map<U>(callbackfn: (value: string | number | boolean, index: number, array: (string | number | boolean)[]) => U, thisArg?: any): U[]; filter<S extends string | number | boolean>(callbackfn: (value: string | number | boolean, index: number, array: (string | number | boolean)[]) => value is S, thisArg?: any): S[]; filter(callbackfn: (value: string | number | boolean, index: number, array: (string | number | boolean)[]) => unknown, thisArg?: any): (string | number | boolean)[]; reduce(callbackfn: (previousValue: string | number | boolean, currentValue: string | number | boolean, currentIndex: number, array: (string | number | boolean)[]) => string | number | boolean): string | number | boolean; reduce(callbackfn: (previousValue: string | number | boolean, currentValue: string | number | boolean, currentIndex: number, array: (string | number | boolean)[]) => string | number | boolean, initialValue: string | number | boolean): string | number | boolean; reduce<U>(callbackfn: (previousValue: U, currentValue: string | number | boolean, currentIndex: number, array: (string | number | boolean)[]) => U, initialValue: U): U; reduceRight(callbackfn: (previousValue: string | number | boolean, currentValue: string | number | boolean, currentIndex: number, array: (string | number | boolean)[]) => string | number | boolean): string | number | boolean; reduceRight(callbackfn: (previousValue: string | number | boolean, currentValue: string | number | boolean, currentIndex: number, array: (string | number | boolean)[]) => string | number | boolean, initialValue: string | number | boolean): string | number | boolean; reduceRight<U>(callbackfn: (previousValue: U, currentValue: string | number | boolean, currentIndex: number, array: (string | number | boolean)[]) => U, initialValue: U): U; }
+>rest : { [n: number]: string | number | boolean; 0: boolean; 1: string; 2: number; length: 3; toString(): string; toLocaleString(): string; pop(): string | number | boolean; push(...items: (string | number | boolean)[]): number; concat(...items: ConcatArray<string | number | boolean>[]): (string | number | boolean)[]; concat(...items: (string | number | boolean | ConcatArray<string | number | boolean>)[]): (string | number | boolean)[]; join(separator?: string): string; reverse(): (string | number | boolean)[]; shift(): string | number | boolean; slice(start?: number, end?: number): (string | number | boolean)[]; sort(compareFn?: (a: string | number | boolean, b: string | number | boolean) => number): [boolean, string, number]; splice(start: number, deleteCount?: number): (string | number | boolean)[]; splice(start: number, deleteCount: number, ...items: (string | number | boolean)[]): (string | number | boolean)[]; unshift(...items: (string | number | boolean)[]): number; indexOf(searchElement: string | number | boolean, fromIndex?: number): number; lastIndexOf(searchElement: string | number | boolean, fromIndex?: number): number; every(callbackfn: (value: string | number | boolean, index: number, array: (string | number | boolean)[]) => unknown, thisArg?: any): boolean; some(callbackfn: (value: string | number | boolean, index: number, array: (string | number | boolean)[]) => unknown, thisArg?: any): boolean; forEach(callbackfn: (value: string | number | boolean, index: number, array: (string | number | boolean)[]) => void, thisArg?: any): void; map<U>(callbackfn: (value: string | number | boolean, index: number, array: (string | number | boolean)[]) => U, thisArg?: any): [U, U, U]; filter<S extends string | number | boolean>(callbackfn: (value: string | number | boolean, index: number, array: (string | number | boolean)[]) => value is S, thisArg?: any): S[]; filter(callbackfn: (value: string | number | boolean, index: number, array: (string | number | boolean)[]) => unknown, thisArg?: any): (string | number | boolean)[]; reduce(callbackfn: (previousValue: string | number | boolean, currentValue: string | number | boolean, currentIndex: number, array: (string | number | boolean)[]) => string | number | boolean): string | number | boolean; reduce(callbackfn: (previousValue: string | number | boolean, currentValue: string | number | boolean, currentIndex: number, array: (string | number | boolean)[]) => string | number | boolean, initialValue: string | number | boolean): string | number | boolean; reduce<U>(callbackfn: (previousValue: U, currentValue: string | number | boolean, currentIndex: number, array: (string | number | boolean)[]) => U, initialValue: U): U; reduceRight(callbackfn: (previousValue: string | number | boolean, currentValue: string | number | boolean, currentIndex: number, array: (string | number | boolean)[]) => string | number | boolean): string | number | boolean; reduceRight(callbackfn: (previousValue: string | number | boolean, currentValue: string | number | boolean, currentIndex: number, array: (string | number | boolean)[]) => string | number | boolean, initialValue: string | number | boolean): string | number | boolean; reduceRight<U>(callbackfn: (previousValue: U, currentValue: string | number | boolean, currentIndex: number, array: (string | number | boolean)[]) => U, initialValue: U): U; }
 
diff --git a/tests/baselines/reference/restParametersOfNonArrayTypes2.errors.txt b/tests/baselines/reference/restParametersOfNonArrayTypes2.errors.txt
index 5c31031cba4bc..654f053e8bb62 100644
--- a/tests/baselines/reference/restParametersOfNonArrayTypes2.errors.txt
+++ b/tests/baselines/reference/restParametersOfNonArrayTypes2.errors.txt
@@ -1,12 +1,40 @@
+tests/cases/conformance/types/objectTypeLiteral/callSignatures/restParametersOfNonArrayTypes2.ts(7,14): error TS2370: A rest parameter must be of an array type.
+tests/cases/conformance/types/objectTypeLiteral/callSignatures/restParametersOfNonArrayTypes2.ts(8,22): error TS2370: A rest parameter must be of an array type.
 tests/cases/conformance/types/objectTypeLiteral/callSignatures/restParametersOfNonArrayTypes2.ts(9,11): error TS1014: A rest parameter must be last in a parameter list.
+tests/cases/conformance/types/objectTypeLiteral/callSignatures/restParametersOfNonArrayTypes2.ts(9,11): error TS2370: A rest parameter must be of an array type.
+tests/cases/conformance/types/objectTypeLiteral/callSignatures/restParametersOfNonArrayTypes2.ts(9,26): error TS2370: A rest parameter must be of an array type.
+tests/cases/conformance/types/objectTypeLiteral/callSignatures/restParametersOfNonArrayTypes2.ts(12,9): error TS2370: A rest parameter must be of an array type.
+tests/cases/conformance/types/objectTypeLiteral/callSignatures/restParametersOfNonArrayTypes2.ts(16,6): error TS2370: A rest parameter must be of an array type.
 tests/cases/conformance/types/objectTypeLiteral/callSignatures/restParametersOfNonArrayTypes2.ts(17,9): error TS1014: A rest parameter must be last in a parameter list.
+tests/cases/conformance/types/objectTypeLiteral/callSignatures/restParametersOfNonArrayTypes2.ts(17,9): error TS2370: A rest parameter must be of an array type.
+tests/cases/conformance/types/objectTypeLiteral/callSignatures/restParametersOfNonArrayTypes2.ts(17,24): error TS2370: A rest parameter must be of an array type.
+tests/cases/conformance/types/objectTypeLiteral/callSignatures/restParametersOfNonArrayTypes2.ts(21,6): error TS2370: A rest parameter must be of an array type.
+tests/cases/conformance/types/objectTypeLiteral/callSignatures/restParametersOfNonArrayTypes2.ts(22,9): error TS2370: A rest parameter must be of an array type.
+tests/cases/conformance/types/objectTypeLiteral/callSignatures/restParametersOfNonArrayTypes2.ts(26,9): error TS2370: A rest parameter must be of an array type.
 tests/cases/conformance/types/objectTypeLiteral/callSignatures/restParametersOfNonArrayTypes2.ts(27,21): error TS1014: A rest parameter must be last in a parameter list.
+tests/cases/conformance/types/objectTypeLiteral/callSignatures/restParametersOfNonArrayTypes2.ts(27,21): error TS2370: A rest parameter must be of an array type.
+tests/cases/conformance/types/objectTypeLiteral/callSignatures/restParametersOfNonArrayTypes2.ts(27,36): error TS2370: A rest parameter must be of an array type.
+tests/cases/conformance/types/objectTypeLiteral/callSignatures/restParametersOfNonArrayTypes2.ts(28,9): error TS2370: A rest parameter must be of an array type.
+tests/cases/conformance/types/objectTypeLiteral/callSignatures/restParametersOfNonArrayTypes2.ts(34,15): error TS2370: A rest parameter must be of an array type.
+tests/cases/conformance/types/objectTypeLiteral/callSignatures/restParametersOfNonArrayTypes2.ts(35,23): error TS2370: A rest parameter must be of an array type.
 tests/cases/conformance/types/objectTypeLiteral/callSignatures/restParametersOfNonArrayTypes2.ts(36,11): error TS1014: A rest parameter must be last in a parameter list.
+tests/cases/conformance/types/objectTypeLiteral/callSignatures/restParametersOfNonArrayTypes2.ts(36,11): error TS2370: A rest parameter must be of an array type.
+tests/cases/conformance/types/objectTypeLiteral/callSignatures/restParametersOfNonArrayTypes2.ts(36,35): error TS2370: A rest parameter must be of an array type.
+tests/cases/conformance/types/objectTypeLiteral/callSignatures/restParametersOfNonArrayTypes2.ts(39,9): error TS2370: A rest parameter must be of an array type.
+tests/cases/conformance/types/objectTypeLiteral/callSignatures/restParametersOfNonArrayTypes2.ts(43,6): error TS2370: A rest parameter must be of an array type.
 tests/cases/conformance/types/objectTypeLiteral/callSignatures/restParametersOfNonArrayTypes2.ts(44,9): error TS1014: A rest parameter must be last in a parameter list.
+tests/cases/conformance/types/objectTypeLiteral/callSignatures/restParametersOfNonArrayTypes2.ts(44,9): error TS2370: A rest parameter must be of an array type.
+tests/cases/conformance/types/objectTypeLiteral/callSignatures/restParametersOfNonArrayTypes2.ts(44,33): error TS2370: A rest parameter must be of an array type.
+tests/cases/conformance/types/objectTypeLiteral/callSignatures/restParametersOfNonArrayTypes2.ts(48,6): error TS2370: A rest parameter must be of an array type.
+tests/cases/conformance/types/objectTypeLiteral/callSignatures/restParametersOfNonArrayTypes2.ts(49,9): error TS2370: A rest parameter must be of an array type.
+tests/cases/conformance/types/objectTypeLiteral/callSignatures/restParametersOfNonArrayTypes2.ts(53,9): error TS2370: A rest parameter must be of an array type.
 tests/cases/conformance/types/objectTypeLiteral/callSignatures/restParametersOfNonArrayTypes2.ts(54,21): error TS1014: A rest parameter must be last in a parameter list.
+tests/cases/conformance/types/objectTypeLiteral/callSignatures/restParametersOfNonArrayTypes2.ts(54,21): error TS2370: A rest parameter must be of an array type.
+tests/cases/conformance/types/objectTypeLiteral/callSignatures/restParametersOfNonArrayTypes2.ts(54,45): error TS2370: A rest parameter must be of an array type.
+tests/cases/conformance/types/objectTypeLiteral/callSignatures/restParametersOfNonArrayTypes2.ts(55,9): error TS2370: A rest parameter must be of an array type.
 
 
-==== tests/cases/conformance/types/objectTypeLiteral/callSignatures/restParametersOfNonArrayTypes2.ts (6 errors) ====
+==== tests/cases/conformance/types/objectTypeLiteral/callSignatures/restParametersOfNonArrayTypes2.ts (34 errors) ====
     // Rest parameters must be an array type if they have a type annotation, 
     // user defined subtypes of array do not count, all of these are errors
     
@@ -14,64 +42,120 @@ tests/cases/conformance/types/objectTypeLiteral/callSignatures/restParametersOfN
     interface MyThing2<T> extends Array<T> { }
     
     function foo(...x: MyThing) { }
+                 ~~~~~~~~~~~~~
+!!! error TS2370: A rest parameter must be of an array type.
     var f = function foo(...x: MyThing) { }
+                         ~~~~~~~~~~~~~
+!!! error TS2370: A rest parameter must be of an array type.
     var f2 = (...x: MyThing, ...y: MyThing) => { }
               ~~~
 !!! error TS1014: A rest parameter must be last in a parameter list.
+              ~~~~~~~~~~~~~
+!!! error TS2370: A rest parameter must be of an array type.
+                             ~~~~~~~~~~~~~
+!!! error TS2370: A rest parameter must be of an array type.
     
     class C {
         foo(...x: MyThing) { }
+            ~~~~~~~~~~~~~
+!!! error TS2370: A rest parameter must be of an array type.
     }
     
     interface I {
         (...x: MyThing);
+         ~~~~~~~~~~~~~
+!!! error TS2370: A rest parameter must be of an array type.
         foo(...x: MyThing, ...y: MyThing);
             ~~~
 !!! error TS1014: A rest parameter must be last in a parameter list.
+            ~~~~~~~~~~~~~
+!!! error TS2370: A rest parameter must be of an array type.
+                           ~~~~~~~~~~~~~
+!!! error TS2370: A rest parameter must be of an array type.
     }
     
     var a: {
         (...x: MyThing);
+         ~~~~~~~~~~~~~
+!!! error TS2370: A rest parameter must be of an array type.
         foo(...x: MyThing);
+            ~~~~~~~~~~~~~
+!!! error TS2370: A rest parameter must be of an array type.
     }
     
     var b = {
         foo(...x: MyThing) { },
+            ~~~~~~~~~~~~~
+!!! error TS2370: A rest parameter must be of an array type.
         a: function foo(...x: MyThing, ...y: MyThing) { },
                         ~~~
 !!! error TS1014: A rest parameter must be last in a parameter list.
+                        ~~~~~~~~~~~~~
+!!! error TS2370: A rest parameter must be of an array type.
+                                       ~~~~~~~~~~~~~
+!!! error TS2370: A rest parameter must be of an array type.
         b: (...x: MyThing) => { }
+            ~~~~~~~~~~~~~
+!!! error TS2370: A rest parameter must be of an array type.
     }
     
     
     
     
     function foo2(...x: MyThing2<string>) { }
+                  ~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2370: A rest parameter must be of an array type.
     var f3 = function foo(...x: MyThing2<string>) { }
+                          ~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2370: A rest parameter must be of an array type.
     var f4 = (...x: MyThing2<string>, ...y: MyThing2<string>) => { }
               ~~~
 !!! error TS1014: A rest parameter must be last in a parameter list.
+              ~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2370: A rest parameter must be of an array type.
+                                      ~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2370: A rest parameter must be of an array type.
     
     class C2 {
         foo(...x: MyThing2<string>) { }
+            ~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2370: A rest parameter must be of an array type.
     }
     
     interface I2 {
         (...x: MyThing2<string>);
+         ~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2370: A rest parameter must be of an array type.
         foo(...x: MyThing2<string>, ...y: MyThing2<string>);
             ~~~
 !!! error TS1014: A rest parameter must be last in a parameter list.
+            ~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2370: A rest parameter must be of an array type.
+                                    ~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2370: A rest parameter must be of an array type.
     }
     
     var a2: {
         (...x: MyThing2<string>);
+         ~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2370: A rest parameter must be of an array type.
         foo(...x: MyThing2<string>);
+            ~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2370: A rest parameter must be of an array type.
     }
     
     var b2 = {
         foo(...x: MyThing2<string>) { },
+            ~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2370: A rest parameter must be of an array type.
         a: function foo(...x: MyThing2<string>, ...y: MyThing2<string>) { },
                         ~~~
 !!! error TS1014: A rest parameter must be last in a parameter list.
+                        ~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2370: A rest parameter must be of an array type.
+                                                ~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2370: A rest parameter must be of an array type.
         b: (...x: MyThing2<string>) => { }
+            ~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2370: A rest parameter must be of an array type.
     }
\ No newline at end of file