From 245f7a8ef4d15b058e08f92049a6b1c50c010d23 Mon Sep 17 00:00:00 2001
From: Anders Hejlsberg <andersh@microsoft.com>
Date: Tue, 4 Aug 2015 11:42:58 -0700
Subject: [PATCH 1/2] Add explicit handling of tuple-to-tuple type inference

---
 src/compiler/checker.ts | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index c37189488b..95bd110787 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -5732,6 +5732,14 @@ namespace ts {
                         inferFromTypes(sourceTypes[i], targetTypes[i]);
                     }
                 }
+                else if (source.flags & TypeFlags.Tuple && target.flags & TypeFlags.Tuple && (<TupleType>source).elementTypes.length === (<TupleType>target).elementTypes.length) {
+                    // If source and target are tuples of the same size, infer from element types
+                    let sourceTypes = (<TupleType>source).elementTypes;
+                    let targetTypes = (<TupleType>target).elementTypes;
+                    for (let i = 0; i < sourceTypes.length; i++) {
+                        inferFromTypes(sourceTypes[i], targetTypes[i]);
+                    }
+                }
                 else if (target.flags & TypeFlags.UnionOrIntersection) {
                     let targetTypes = (<UnionOrIntersectionType>target).types;
                     let typeParameterCount = 0;

From 81544d4652850955969daf5ea1d1c62b8f8a7510 Mon Sep 17 00:00:00 2001
From: Anders Hejlsberg <andersh@microsoft.com>
Date: Tue, 4 Aug 2015 11:43:13 -0700
Subject: [PATCH 2/2] Adding test case

---
 .../baselines/reference/tupleTypeInference.js |  31 +++++
 .../reference/tupleTypeInference.symbols      | 110 ++++++++++++++++
 .../reference/tupleTypeInference.types        | 122 ++++++++++++++++++
 tests/cases/compiler/tupleTypeInference.ts    |  21 +++
 4 files changed, 284 insertions(+)
 create mode 100644 tests/baselines/reference/tupleTypeInference.js
 create mode 100644 tests/baselines/reference/tupleTypeInference.symbols
 create mode 100644 tests/baselines/reference/tupleTypeInference.types
 create mode 100644 tests/cases/compiler/tupleTypeInference.ts

diff --git a/tests/baselines/reference/tupleTypeInference.js b/tests/baselines/reference/tupleTypeInference.js
new file mode 100644
index 0000000000..dfc0de8302
--- /dev/null
+++ b/tests/baselines/reference/tupleTypeInference.js
@@ -0,0 +1,31 @@
+//// [tupleTypeInference.ts]
+declare var $q: IQService;
+
+interface IQService {
+    all<T1, T2, T3>(x: [IPromise<T1>, IPromise<T2>, IPromise<T3>]): IPromise<[T1, T2, T3]>;
+    all<T1, T2>(x: [IPromise<T1>, IPromise<T2>]): IPromise<[T1, T2]>;
+    all<T1>(x: [IPromise<T1>]): IPromise<[T1]>;
+    when<T>(t?: T): IPromise<T>;
+}
+
+interface IPromise<T> {
+    then<TResult>(callback: (t: T) => TResult): IPromise<TResult>;
+}
+
+// Implicit different types
+var a = $q.all([$q.when<string>(), $q.when<number>()]);
+
+// Explicit different types
+var b = $q.all<string, number>([$q.when<string>(), $q.when<number>()]);
+
+// Implicit identical types
+var c = $q.all([$q.when<string>(), $q.when<string>()]);
+
+
+//// [tupleTypeInference.js]
+// Implicit different types
+var a = $q.all([$q.when(), $q.when()]);
+// Explicit different types
+var b = $q.all([$q.when(), $q.when()]);
+// Implicit identical types
+var c = $q.all([$q.when(), $q.when()]);
diff --git a/tests/baselines/reference/tupleTypeInference.symbols b/tests/baselines/reference/tupleTypeInference.symbols
new file mode 100644
index 0000000000..4dbed73e39
--- /dev/null
+++ b/tests/baselines/reference/tupleTypeInference.symbols
@@ -0,0 +1,110 @@
+=== tests/cases/compiler/tupleTypeInference.ts ===
+declare var $q: IQService;
+>$q : Symbol($q, Decl(tupleTypeInference.ts, 0, 11))
+>IQService : Symbol(IQService, Decl(tupleTypeInference.ts, 0, 26))
+
+interface IQService {
+>IQService : Symbol(IQService, Decl(tupleTypeInference.ts, 0, 26))
+
+    all<T1, T2, T3>(x: [IPromise<T1>, IPromise<T2>, IPromise<T3>]): IPromise<[T1, T2, T3]>;
+>all : Symbol(all, Decl(tupleTypeInference.ts, 2, 21), Decl(tupleTypeInference.ts, 3, 91), Decl(tupleTypeInference.ts, 4, 69))
+>T1 : Symbol(T1, Decl(tupleTypeInference.ts, 3, 8))
+>T2 : Symbol(T2, Decl(tupleTypeInference.ts, 3, 11))
+>T3 : Symbol(T3, Decl(tupleTypeInference.ts, 3, 15))
+>x : Symbol(x, Decl(tupleTypeInference.ts, 3, 20))
+>IPromise : Symbol(IPromise, Decl(tupleTypeInference.ts, 7, 1))
+>T1 : Symbol(T1, Decl(tupleTypeInference.ts, 3, 8))
+>IPromise : Symbol(IPromise, Decl(tupleTypeInference.ts, 7, 1))
+>T2 : Symbol(T2, Decl(tupleTypeInference.ts, 3, 11))
+>IPromise : Symbol(IPromise, Decl(tupleTypeInference.ts, 7, 1))
+>T3 : Symbol(T3, Decl(tupleTypeInference.ts, 3, 15))
+>IPromise : Symbol(IPromise, Decl(tupleTypeInference.ts, 7, 1))
+>T1 : Symbol(T1, Decl(tupleTypeInference.ts, 3, 8))
+>T2 : Symbol(T2, Decl(tupleTypeInference.ts, 3, 11))
+>T3 : Symbol(T3, Decl(tupleTypeInference.ts, 3, 15))
+
+    all<T1, T2>(x: [IPromise<T1>, IPromise<T2>]): IPromise<[T1, T2]>;
+>all : Symbol(all, Decl(tupleTypeInference.ts, 2, 21), Decl(tupleTypeInference.ts, 3, 91), Decl(tupleTypeInference.ts, 4, 69))
+>T1 : Symbol(T1, Decl(tupleTypeInference.ts, 4, 8))
+>T2 : Symbol(T2, Decl(tupleTypeInference.ts, 4, 11))
+>x : Symbol(x, Decl(tupleTypeInference.ts, 4, 16))
+>IPromise : Symbol(IPromise, Decl(tupleTypeInference.ts, 7, 1))
+>T1 : Symbol(T1, Decl(tupleTypeInference.ts, 4, 8))
+>IPromise : Symbol(IPromise, Decl(tupleTypeInference.ts, 7, 1))
+>T2 : Symbol(T2, Decl(tupleTypeInference.ts, 4, 11))
+>IPromise : Symbol(IPromise, Decl(tupleTypeInference.ts, 7, 1))
+>T1 : Symbol(T1, Decl(tupleTypeInference.ts, 4, 8))
+>T2 : Symbol(T2, Decl(tupleTypeInference.ts, 4, 11))
+
+    all<T1>(x: [IPromise<T1>]): IPromise<[T1]>;
+>all : Symbol(all, Decl(tupleTypeInference.ts, 2, 21), Decl(tupleTypeInference.ts, 3, 91), Decl(tupleTypeInference.ts, 4, 69))
+>T1 : Symbol(T1, Decl(tupleTypeInference.ts, 5, 8))
+>x : Symbol(x, Decl(tupleTypeInference.ts, 5, 12))
+>IPromise : Symbol(IPromise, Decl(tupleTypeInference.ts, 7, 1))
+>T1 : Symbol(T1, Decl(tupleTypeInference.ts, 5, 8))
+>IPromise : Symbol(IPromise, Decl(tupleTypeInference.ts, 7, 1))
+>T1 : Symbol(T1, Decl(tupleTypeInference.ts, 5, 8))
+
+    when<T>(t?: T): IPromise<T>;
+>when : Symbol(when, Decl(tupleTypeInference.ts, 5, 47))
+>T : Symbol(T, Decl(tupleTypeInference.ts, 6, 9))
+>t : Symbol(t, Decl(tupleTypeInference.ts, 6, 12))
+>T : Symbol(T, Decl(tupleTypeInference.ts, 6, 9))
+>IPromise : Symbol(IPromise, Decl(tupleTypeInference.ts, 7, 1))
+>T : Symbol(T, Decl(tupleTypeInference.ts, 6, 9))
+}
+
+interface IPromise<T> {
+>IPromise : Symbol(IPromise, Decl(tupleTypeInference.ts, 7, 1))
+>T : Symbol(T, Decl(tupleTypeInference.ts, 9, 19))
+
+    then<TResult>(callback: (t: T) => TResult): IPromise<TResult>;
+>then : Symbol(then, Decl(tupleTypeInference.ts, 9, 23))
+>TResult : Symbol(TResult, Decl(tupleTypeInference.ts, 10, 9))
+>callback : Symbol(callback, Decl(tupleTypeInference.ts, 10, 18))
+>t : Symbol(t, Decl(tupleTypeInference.ts, 10, 29))
+>T : Symbol(T, Decl(tupleTypeInference.ts, 9, 19))
+>TResult : Symbol(TResult, Decl(tupleTypeInference.ts, 10, 9))
+>IPromise : Symbol(IPromise, Decl(tupleTypeInference.ts, 7, 1))
+>TResult : Symbol(TResult, Decl(tupleTypeInference.ts, 10, 9))
+}
+
+// Implicit different types
+var a = $q.all([$q.when<string>(), $q.when<number>()]);
+>a : Symbol(a, Decl(tupleTypeInference.ts, 14, 3))
+>$q.all : Symbol(IQService.all, Decl(tupleTypeInference.ts, 2, 21), Decl(tupleTypeInference.ts, 3, 91), Decl(tupleTypeInference.ts, 4, 69))
+>$q : Symbol($q, Decl(tupleTypeInference.ts, 0, 11))
+>all : Symbol(IQService.all, Decl(tupleTypeInference.ts, 2, 21), Decl(tupleTypeInference.ts, 3, 91), Decl(tupleTypeInference.ts, 4, 69))
+>$q.when : Symbol(IQService.when, Decl(tupleTypeInference.ts, 5, 47))
+>$q : Symbol($q, Decl(tupleTypeInference.ts, 0, 11))
+>when : Symbol(IQService.when, Decl(tupleTypeInference.ts, 5, 47))
+>$q.when : Symbol(IQService.when, Decl(tupleTypeInference.ts, 5, 47))
+>$q : Symbol($q, Decl(tupleTypeInference.ts, 0, 11))
+>when : Symbol(IQService.when, Decl(tupleTypeInference.ts, 5, 47))
+
+// Explicit different types
+var b = $q.all<string, number>([$q.when<string>(), $q.when<number>()]);
+>b : Symbol(b, Decl(tupleTypeInference.ts, 17, 3))
+>$q.all : Symbol(IQService.all, Decl(tupleTypeInference.ts, 2, 21), Decl(tupleTypeInference.ts, 3, 91), Decl(tupleTypeInference.ts, 4, 69))
+>$q : Symbol($q, Decl(tupleTypeInference.ts, 0, 11))
+>all : Symbol(IQService.all, Decl(tupleTypeInference.ts, 2, 21), Decl(tupleTypeInference.ts, 3, 91), Decl(tupleTypeInference.ts, 4, 69))
+>$q.when : Symbol(IQService.when, Decl(tupleTypeInference.ts, 5, 47))
+>$q : Symbol($q, Decl(tupleTypeInference.ts, 0, 11))
+>when : Symbol(IQService.when, Decl(tupleTypeInference.ts, 5, 47))
+>$q.when : Symbol(IQService.when, Decl(tupleTypeInference.ts, 5, 47))
+>$q : Symbol($q, Decl(tupleTypeInference.ts, 0, 11))
+>when : Symbol(IQService.when, Decl(tupleTypeInference.ts, 5, 47))
+
+// Implicit identical types
+var c = $q.all([$q.when<string>(), $q.when<string>()]);
+>c : Symbol(c, Decl(tupleTypeInference.ts, 20, 3))
+>$q.all : Symbol(IQService.all, Decl(tupleTypeInference.ts, 2, 21), Decl(tupleTypeInference.ts, 3, 91), Decl(tupleTypeInference.ts, 4, 69))
+>$q : Symbol($q, Decl(tupleTypeInference.ts, 0, 11))
+>all : Symbol(IQService.all, Decl(tupleTypeInference.ts, 2, 21), Decl(tupleTypeInference.ts, 3, 91), Decl(tupleTypeInference.ts, 4, 69))
+>$q.when : Symbol(IQService.when, Decl(tupleTypeInference.ts, 5, 47))
+>$q : Symbol($q, Decl(tupleTypeInference.ts, 0, 11))
+>when : Symbol(IQService.when, Decl(tupleTypeInference.ts, 5, 47))
+>$q.when : Symbol(IQService.when, Decl(tupleTypeInference.ts, 5, 47))
+>$q : Symbol($q, Decl(tupleTypeInference.ts, 0, 11))
+>when : Symbol(IQService.when, Decl(tupleTypeInference.ts, 5, 47))
+
diff --git a/tests/baselines/reference/tupleTypeInference.types b/tests/baselines/reference/tupleTypeInference.types
new file mode 100644
index 0000000000..999574a78e
--- /dev/null
+++ b/tests/baselines/reference/tupleTypeInference.types
@@ -0,0 +1,122 @@
+=== tests/cases/compiler/tupleTypeInference.ts ===
+declare var $q: IQService;
+>$q : IQService
+>IQService : IQService
+
+interface IQService {
+>IQService : IQService
+
+    all<T1, T2, T3>(x: [IPromise<T1>, IPromise<T2>, IPromise<T3>]): IPromise<[T1, T2, T3]>;
+>all : { <T1, T2, T3>(x: [IPromise<T1>, IPromise<T2>, IPromise<T3>]): IPromise<[T1, T2, T3]>; <T1, T2>(x: [IPromise<T1>, IPromise<T2>]): IPromise<[T1, T2]>; <T1>(x: [IPromise<T1>]): IPromise<[T1]>; }
+>T1 : T1
+>T2 : T2
+>T3 : T3
+>x : [IPromise<T1>, IPromise<T2>, IPromise<T3>]
+>IPromise : IPromise<T>
+>T1 : T1
+>IPromise : IPromise<T>
+>T2 : T2
+>IPromise : IPromise<T>
+>T3 : T3
+>IPromise : IPromise<T>
+>T1 : T1
+>T2 : T2
+>T3 : T3
+
+    all<T1, T2>(x: [IPromise<T1>, IPromise<T2>]): IPromise<[T1, T2]>;
+>all : { <T1, T2, T3>(x: [IPromise<T1>, IPromise<T2>, IPromise<T3>]): IPromise<[T1, T2, T3]>; <T1, T2>(x: [IPromise<T1>, IPromise<T2>]): IPromise<[T1, T2]>; <T1>(x: [IPromise<T1>]): IPromise<[T1]>; }
+>T1 : T1
+>T2 : T2
+>x : [IPromise<T1>, IPromise<T2>]
+>IPromise : IPromise<T>
+>T1 : T1
+>IPromise : IPromise<T>
+>T2 : T2
+>IPromise : IPromise<T>
+>T1 : T1
+>T2 : T2
+
+    all<T1>(x: [IPromise<T1>]): IPromise<[T1]>;
+>all : { <T1, T2, T3>(x: [IPromise<T1>, IPromise<T2>, IPromise<T3>]): IPromise<[T1, T2, T3]>; <T1, T2>(x: [IPromise<T1>, IPromise<T2>]): IPromise<[T1, T2]>; <T1>(x: [IPromise<T1>]): IPromise<[T1]>; }
+>T1 : T1
+>x : [IPromise<T1>]
+>IPromise : IPromise<T>
+>T1 : T1
+>IPromise : IPromise<T>
+>T1 : T1
+
+    when<T>(t?: T): IPromise<T>;
+>when : <T>(t?: T) => IPromise<T>
+>T : T
+>t : T
+>T : T
+>IPromise : IPromise<T>
+>T : T
+}
+
+interface IPromise<T> {
+>IPromise : IPromise<T>
+>T : T
+
+    then<TResult>(callback: (t: T) => TResult): IPromise<TResult>;
+>then : <TResult>(callback: (t: T) => TResult) => IPromise<TResult>
+>TResult : TResult
+>callback : (t: T) => TResult
+>t : T
+>T : T
+>TResult : TResult
+>IPromise : IPromise<T>
+>TResult : TResult
+}
+
+// Implicit different types
+var a = $q.all([$q.when<string>(), $q.when<number>()]);
+>a : IPromise<[string, number]>
+>$q.all([$q.when<string>(), $q.when<number>()]) : IPromise<[string, number]>
+>$q.all : { <T1, T2, T3>(x: [IPromise<T1>, IPromise<T2>, IPromise<T3>]): IPromise<[T1, T2, T3]>; <T1, T2>(x: [IPromise<T1>, IPromise<T2>]): IPromise<[T1, T2]>; <T1>(x: [IPromise<T1>]): IPromise<[T1]>; }
+>$q : IQService
+>all : { <T1, T2, T3>(x: [IPromise<T1>, IPromise<T2>, IPromise<T3>]): IPromise<[T1, T2, T3]>; <T1, T2>(x: [IPromise<T1>, IPromise<T2>]): IPromise<[T1, T2]>; <T1>(x: [IPromise<T1>]): IPromise<[T1]>; }
+>[$q.when<string>(), $q.when<number>()] : [IPromise<string>, IPromise<number>]
+>$q.when<string>() : IPromise<string>
+>$q.when : <T>(t?: T) => IPromise<T>
+>$q : IQService
+>when : <T>(t?: T) => IPromise<T>
+>$q.when<number>() : IPromise<number>
+>$q.when : <T>(t?: T) => IPromise<T>
+>$q : IQService
+>when : <T>(t?: T) => IPromise<T>
+
+// Explicit different types
+var b = $q.all<string, number>([$q.when<string>(), $q.when<number>()]);
+>b : IPromise<[string, number]>
+>$q.all<string, number>([$q.when<string>(), $q.when<number>()]) : IPromise<[string, number]>
+>$q.all : { <T1, T2, T3>(x: [IPromise<T1>, IPromise<T2>, IPromise<T3>]): IPromise<[T1, T2, T3]>; <T1, T2>(x: [IPromise<T1>, IPromise<T2>]): IPromise<[T1, T2]>; <T1>(x: [IPromise<T1>]): IPromise<[T1]>; }
+>$q : IQService
+>all : { <T1, T2, T3>(x: [IPromise<T1>, IPromise<T2>, IPromise<T3>]): IPromise<[T1, T2, T3]>; <T1, T2>(x: [IPromise<T1>, IPromise<T2>]): IPromise<[T1, T2]>; <T1>(x: [IPromise<T1>]): IPromise<[T1]>; }
+>[$q.when<string>(), $q.when<number>()] : [IPromise<string>, IPromise<number>]
+>$q.when<string>() : IPromise<string>
+>$q.when : <T>(t?: T) => IPromise<T>
+>$q : IQService
+>when : <T>(t?: T) => IPromise<T>
+>$q.when<number>() : IPromise<number>
+>$q.when : <T>(t?: T) => IPromise<T>
+>$q : IQService
+>when : <T>(t?: T) => IPromise<T>
+
+// Implicit identical types
+var c = $q.all([$q.when<string>(), $q.when<string>()]);
+>c : IPromise<[string, string]>
+>$q.all([$q.when<string>(), $q.when<string>()]) : IPromise<[string, string]>
+>$q.all : { <T1, T2, T3>(x: [IPromise<T1>, IPromise<T2>, IPromise<T3>]): IPromise<[T1, T2, T3]>; <T1, T2>(x: [IPromise<T1>, IPromise<T2>]): IPromise<[T1, T2]>; <T1>(x: [IPromise<T1>]): IPromise<[T1]>; }
+>$q : IQService
+>all : { <T1, T2, T3>(x: [IPromise<T1>, IPromise<T2>, IPromise<T3>]): IPromise<[T1, T2, T3]>; <T1, T2>(x: [IPromise<T1>, IPromise<T2>]): IPromise<[T1, T2]>; <T1>(x: [IPromise<T1>]): IPromise<[T1]>; }
+>[$q.when<string>(), $q.when<string>()] : [IPromise<string>, IPromise<string>]
+>$q.when<string>() : IPromise<string>
+>$q.when : <T>(t?: T) => IPromise<T>
+>$q : IQService
+>when : <T>(t?: T) => IPromise<T>
+>$q.when<string>() : IPromise<string>
+>$q.when : <T>(t?: T) => IPromise<T>
+>$q : IQService
+>when : <T>(t?: T) => IPromise<T>
+
diff --git a/tests/cases/compiler/tupleTypeInference.ts b/tests/cases/compiler/tupleTypeInference.ts
new file mode 100644
index 0000000000..7c5a49d3ca
--- /dev/null
+++ b/tests/cases/compiler/tupleTypeInference.ts
@@ -0,0 +1,21 @@
+declare var $q: IQService;
+
+interface IQService {
+    all<T1, T2, T3>(x: [IPromise<T1>, IPromise<T2>, IPromise<T3>]): IPromise<[T1, T2, T3]>;
+    all<T1, T2>(x: [IPromise<T1>, IPromise<T2>]): IPromise<[T1, T2]>;
+    all<T1>(x: [IPromise<T1>]): IPromise<[T1]>;
+    when<T>(t?: T): IPromise<T>;
+}
+
+interface IPromise<T> {
+    then<TResult>(callback: (t: T) => TResult): IPromise<TResult>;
+}
+
+// Implicit different types
+var a = $q.all([$q.when<string>(), $q.when<number>()]);
+
+// Explicit different types
+var b = $q.all<string, number>([$q.when<string>(), $q.when<number>()]);
+
+// Implicit identical types
+var c = $q.all([$q.when<string>(), $q.when<string>()]);