Cherry-pick PR #33150 into release-3.6 (#33285)

Component commits: b86c86d Add heuristic for extracting irreducible `null` and `undefined` types from intersections of unions
microsoft · Sep 6, 2019 · 1b2ffa9 · 1b2ffa9
1 parent acbcc0d
commit 1b2ffa9
Show file tree

Hide file tree

Showing 5 changed files with 677 additions and 0 deletions.
diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
@@ -9980,6 +9980,16 @@ namespace ts {
             return true;
         }
 
+        function extractIrreducible(types: Type[], flag: TypeFlags) {
+            if (every(types, t => !!(t.flags & TypeFlags.Union) && some((t as UnionType).types, tt => !!(tt.flags & flag)))) {
+                for (let i = 0; i < types.length; i++) {
+                    types[i] = filterType(types[i], t => !(t.flags & flag));
+                }
+                return true;
+            }
+            return false;
+        }
+
         // If the given list of types contains more than one union of primitive types, replace the
         // first with a union containing an intersection of those primitive types, then remove the
         // other unions and return true. Otherwise, do nothing and return false.
@@ -10098,6 +10108,12 @@ namespace ts {
                         // reduced we'll never reduce again, so this occurs at most once.
                         result = getIntersectionType(typeSet, aliasSymbol, aliasTypeArguments);
                     }
+                    else if (extractIrreducible(typeSet, TypeFlags.Undefined)) {
+                        result = getUnionType([getIntersectionType(typeSet), undefinedType], UnionReduction.Literal, aliasSymbol, aliasTypeArguments);
+                    }
+                    else if (extractIrreducible(typeSet, TypeFlags.Null)) {
+                        result = getUnionType([getIntersectionType(typeSet), nullType], UnionReduction.Literal, aliasSymbol, aliasTypeArguments);
+                    }
                     else {
                         // We are attempting to construct a type of the form X & (A | B) & Y. Transform this into a type of
                         // the form X & A & Y | X & B & Y and recursively reduce until no union type constituents remain.

diff --git a/tests/baselines/reference/partialOfLargeAPIIsAbleToBeWorkedWith.js b/tests/baselines/reference/partialOfLargeAPIIsAbleToBeWorkedWith.js
@@ -0,0 +1,85 @@
+//// [partialOfLargeAPIIsAbleToBeWorkedWith.ts]
+interface MyAPI {
+    0: (x: 0) => string;
+    1: (x: 1) => string;
+    2: (x: 2) => string;
+    3: (x: 3) => string;
+    4: (x: 4) => string;
+    5: (x: 5) => string;
+    6: (x: 6) => string;
+    7: (x: 7) => string;
+    8: (x: 8) => string;
+    9: (x: 9) => string;
+    10: (x: 10) => string;
+    11: (x: 11) => string;
+    12: (x: 12) => string;
+    13: (x: 13) => string;
+    14: (x: 14) => string;
+    15: (x: 15) => string;
+    16: (x: 16) => string;
+    17: (x: 17) => string;
+    18: (x: 18) => string;
+    19: (x: 19) => string;
+    20: (x: 20) => string;
+    21: (x: 21) => string;
+    22: (x: 22) => string;
+    23: (x: 23) => string;
+    24: (x: 24) => string;
+    25: (x: 25) => string;
+    26: (x: 26) => string;
+    27: (x: 27) => string;
+    28: (x: 28) => string;
+    29: (x: 29) => string;
+    30: (x: 30) => string;
+    31: (x: 31) => string;
+    32: (x: 32) => string;
+    33: (x: 33) => string;
+    34: (x: 34) => string;
+    35: (x: 35) => string;
+    36: (x: 36) => string;
+    37: (x: 37) => string;
+    38: (x: 38) => string;
+    39: (x: 39) => string;
+    40: (x: 40) => string;
+    41: (x: 41) => string;
+    42: (x: 42) => string;
+    43: (x: 43) => string;
+    44: (x: 44) => string;
+    45: (x: 45) => string;
+    46: (x: 46) => string;
+    47: (x: 47) => string;
+    48: (x: 48) => string;
+    49: (x: 49) => string;
+    50: (x: 50) => string;
+    51: (x: 51) => string;
+}
+
+const obj: Partial<MyAPI> = {};
+
+declare var keys: (keyof MyAPI)[];
+
+for (const k of keys) {
+    obj[k] = () => "12"; // shouldn't cause a complexity error
+}
+
+type PartialNull<T> = {[K in keyof T]?: T[K] | null};
+
+const obj2: PartialNull<MyAPI> = {};
+
+for (const k of keys) {
+    obj2[k] = () => "12"; // shouldn't cause a complexity error
+}
+
+
+//// [partialOfLargeAPIIsAbleToBeWorkedWith.js]
+"use strict";
+var obj = {};
+for (var _i = 0, keys_1 = keys; _i < keys_1.length; _i++) {
+    var k = keys_1[_i];
+    obj[k] = function () { return "12"; }; // shouldn't cause a complexity error
+}
+var obj2 = {};
+for (var _a = 0, keys_2 = keys; _a < keys_2.length; _a++) {
+    var k = keys_2[_a];
+    obj2[k] = function () { return "12"; }; // shouldn't cause a complexity error
+}
diff --git a/tests/baselines/reference/partialOfLargeAPIIsAbleToBeWorkedWith.symbols b/tests/baselines/reference/partialOfLargeAPIIsAbleToBeWorkedWith.symbols
@@ -0,0 +1,253 @@
+=== tests/cases/compiler/partialOfLargeAPIIsAbleToBeWorkedWith.ts ===
+interface MyAPI {
+>MyAPI : Symbol(MyAPI, Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 0, 0))
+
+    0: (x: 0) => string;
+>0 : Symbol(MyAPI[0], Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 0, 17))
+>x : Symbol(x, Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 1, 8))
+
+    1: (x: 1) => string;
+>1 : Symbol(MyAPI[1], Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 1, 24))
+>x : Symbol(x, Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 2, 8))
+
+    2: (x: 2) => string;
+>2 : Symbol(MyAPI[2], Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 2, 24))
+>x : Symbol(x, Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 3, 8))
+
+    3: (x: 3) => string;
+>3 : Symbol(MyAPI[3], Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 3, 24))
+>x : Symbol(x, Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 4, 8))
+
+    4: (x: 4) => string;
+>4 : Symbol(MyAPI[4], Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 4, 24))
+>x : Symbol(x, Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 5, 8))
+
+    5: (x: 5) => string;
+>5 : Symbol(MyAPI[5], Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 5, 24))
+>x : Symbol(x, Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 6, 8))
+
+    6: (x: 6) => string;
+>6 : Symbol(MyAPI[6], Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 6, 24))
+>x : Symbol(x, Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 7, 8))
+
+    7: (x: 7) => string;
+>7 : Symbol(MyAPI[7], Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 7, 24))
+>x : Symbol(x, Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 8, 8))
+
+    8: (x: 8) => string;
+>8 : Symbol(MyAPI[8], Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 8, 24))
+>x : Symbol(x, Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 9, 8))
+
+    9: (x: 9) => string;
+>9 : Symbol(MyAPI[9], Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 9, 24))
+>x : Symbol(x, Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 10, 8))
+
+    10: (x: 10) => string;
+>10 : Symbol(MyAPI[10], Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 10, 24))
+>x : Symbol(x, Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 11, 9))
+
+    11: (x: 11) => string;
+>11 : Symbol(MyAPI[11], Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 11, 26))
+>x : Symbol(x, Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 12, 9))
+
+    12: (x: 12) => string;
+>12 : Symbol(MyAPI[12], Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 12, 26))
+>x : Symbol(x, Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 13, 9))
+
+    13: (x: 13) => string;
+>13 : Symbol(MyAPI[13], Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 13, 26))
+>x : Symbol(x, Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 14, 9))
+
+    14: (x: 14) => string;
+>14 : Symbol(MyAPI[14], Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 14, 26))
+>x : Symbol(x, Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 15, 9))
+
+    15: (x: 15) => string;
+>15 : Symbol(MyAPI[15], Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 15, 26))
+>x : Symbol(x, Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 16, 9))
+
+    16: (x: 16) => string;
+>16 : Symbol(MyAPI[16], Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 16, 26))
+>x : Symbol(x, Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 17, 9))
+
+    17: (x: 17) => string;
+>17 : Symbol(MyAPI[17], Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 17, 26))
+>x : Symbol(x, Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 18, 9))
+
+    18: (x: 18) => string;
+>18 : Symbol(MyAPI[18], Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 18, 26))
+>x : Symbol(x, Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 19, 9))
+
+    19: (x: 19) => string;
+>19 : Symbol(MyAPI[19], Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 19, 26))
+>x : Symbol(x, Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 20, 9))
+
+    20: (x: 20) => string;
+>20 : Symbol(MyAPI[20], Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 20, 26))
+>x : Symbol(x, Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 21, 9))
+
+    21: (x: 21) => string;
+>21 : Symbol(MyAPI[21], Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 21, 26))
+>x : Symbol(x, Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 22, 9))
+
+    22: (x: 22) => string;
+>22 : Symbol(MyAPI[22], Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 22, 26))
+>x : Symbol(x, Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 23, 9))
+
+    23: (x: 23) => string;
+>23 : Symbol(MyAPI[23], Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 23, 26))
+>x : Symbol(x, Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 24, 9))
+
+    24: (x: 24) => string;
+>24 : Symbol(MyAPI[24], Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 24, 26))
+>x : Symbol(x, Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 25, 9))
+
+    25: (x: 25) => string;
+>25 : Symbol(MyAPI[25], Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 25, 26))
+>x : Symbol(x, Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 26, 9))
+
+    26: (x: 26) => string;
+>26 : Symbol(MyAPI[26], Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 26, 26))
+>x : Symbol(x, Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 27, 9))
+
+    27: (x: 27) => string;
+>27 : Symbol(MyAPI[27], Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 27, 26))
+>x : Symbol(x, Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 28, 9))
+
+    28: (x: 28) => string;
+>28 : Symbol(MyAPI[28], Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 28, 26))
+>x : Symbol(x, Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 29, 9))
+
+    29: (x: 29) => string;
+>29 : Symbol(MyAPI[29], Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 29, 26))
+>x : Symbol(x, Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 30, 9))
+
+    30: (x: 30) => string;
+>30 : Symbol(MyAPI[30], Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 30, 26))
+>x : Symbol(x, Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 31, 9))
+
+    31: (x: 31) => string;
+>31 : Symbol(MyAPI[31], Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 31, 26))
+>x : Symbol(x, Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 32, 9))
+
+    32: (x: 32) => string;
+>32 : Symbol(MyAPI[32], Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 32, 26))
+>x : Symbol(x, Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 33, 9))
+
+    33: (x: 33) => string;
+>33 : Symbol(MyAPI[33], Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 33, 26))
+>x : Symbol(x, Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 34, 9))
+
+    34: (x: 34) => string;
+>34 : Symbol(MyAPI[34], Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 34, 26))
+>x : Symbol(x, Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 35, 9))
+
+    35: (x: 35) => string;
+>35 : Symbol(MyAPI[35], Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 35, 26))
+>x : Symbol(x, Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 36, 9))
+
+    36: (x: 36) => string;
+>36 : Symbol(MyAPI[36], Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 36, 26))
+>x : Symbol(x, Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 37, 9))
+
+    37: (x: 37) => string;
+>37 : Symbol(MyAPI[37], Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 37, 26))
+>x : Symbol(x, Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 38, 9))
+
+    38: (x: 38) => string;
+>38 : Symbol(MyAPI[38], Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 38, 26))
+>x : Symbol(x, Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 39, 9))
+
+    39: (x: 39) => string;
+>39 : Symbol(MyAPI[39], Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 39, 26))
+>x : Symbol(x, Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 40, 9))
+
+    40: (x: 40) => string;
+>40 : Symbol(MyAPI[40], Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 40, 26))
+>x : Symbol(x, Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 41, 9))
+
+    41: (x: 41) => string;
+>41 : Symbol(MyAPI[41], Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 41, 26))
+>x : Symbol(x, Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 42, 9))
+
+    42: (x: 42) => string;
+>42 : Symbol(MyAPI[42], Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 42, 26))
+>x : Symbol(x, Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 43, 9))
+
+    43: (x: 43) => string;
+>43 : Symbol(MyAPI[43], Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 43, 26))
+>x : Symbol(x, Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 44, 9))
+
+    44: (x: 44) => string;
+>44 : Symbol(MyAPI[44], Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 44, 26))
+>x : Symbol(x, Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 45, 9))
+
+    45: (x: 45) => string;
+>45 : Symbol(MyAPI[45], Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 45, 26))
+>x : Symbol(x, Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 46, 9))
+
+    46: (x: 46) => string;
+>46 : Symbol(MyAPI[46], Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 46, 26))
+>x : Symbol(x, Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 47, 9))
+
+    47: (x: 47) => string;
+>47 : Symbol(MyAPI[47], Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 47, 26))
+>x : Symbol(x, Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 48, 9))
+
+    48: (x: 48) => string;
+>48 : Symbol(MyAPI[48], Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 48, 26))
+>x : Symbol(x, Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 49, 9))
+
+    49: (x: 49) => string;
+>49 : Symbol(MyAPI[49], Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 49, 26))
+>x : Symbol(x, Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 50, 9))
+
+    50: (x: 50) => string;
+>50 : Symbol(MyAPI[50], Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 50, 26))
+>x : Symbol(x, Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 51, 9))
+
+    51: (x: 51) => string;
+>51 : Symbol(MyAPI[51], Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 51, 26))
+>x : Symbol(x, Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 52, 9))
+}
+
+const obj: Partial<MyAPI> = {};
+>obj : Symbol(obj, Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 55, 5))
+>Partial : Symbol(Partial, Decl(lib.es5.d.ts, --, --))
+>MyAPI : Symbol(MyAPI, Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 0, 0))
+
+declare var keys: (keyof MyAPI)[];
+>keys : Symbol(keys, Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 57, 11))
+>MyAPI : Symbol(MyAPI, Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 0, 0))
+
+for (const k of keys) {
+>k : Symbol(k, Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 59, 10))
+>keys : Symbol(keys, Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 57, 11))
+
+    obj[k] = () => "12"; // shouldn't cause a complexity error
+>obj : Symbol(obj, Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 55, 5))
+>k : Symbol(k, Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 59, 10))
+}
+
+type PartialNull<T> = {[K in keyof T]?: T[K] | null};
+>PartialNull : Symbol(PartialNull, Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 61, 1))
+>T : Symbol(T, Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 63, 17))
+>K : Symbol(K, Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 63, 24))
+>T : Symbol(T, Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 63, 17))
+>T : Symbol(T, Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 63, 17))
+>K : Symbol(K, Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 63, 24))
+
+const obj2: PartialNull<MyAPI> = {};
+>obj2 : Symbol(obj2, Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 65, 5))
+>PartialNull : Symbol(PartialNull, Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 61, 1))
+>MyAPI : Symbol(MyAPI, Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 0, 0))
+
+for (const k of keys) {
+>k : Symbol(k, Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 67, 10))
+>keys : Symbol(keys, Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 57, 11))
+
+    obj2[k] = () => "12"; // shouldn't cause a complexity error
+>obj2 : Symbol(obj2, Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 65, 5))
+>k : Symbol(k, Decl(partialOfLargeAPIIsAbleToBeWorkedWith.ts, 67, 10))
+}
+