Use type parameter constraints for computed property types

src/compiler/checker.ts

@@ -13330,10 +13330,13 @@ namespace ts {
             const links = getNodeLinks(node.expression);
             if (!links.resolvedType) {
                 links.resolvedType = checkExpression(node.expression);
+                const t = links.resolvedType.flags & TypeFlags.TypeVariable ?
+                    getBaseConstraintOfType(links.resolvedType) || emptyObjectType :
+                    links.resolvedType;
 
                 // This will allow types number, string, symbol or any. It will also allow enums, the unknown
                 // type, and any union of these types (like string | number).
-                if (!isTypeAnyOrAllConstituentTypesHaveKind(links.resolvedType, TypeFlags.NumberLike | TypeFlags.StringLike | TypeFlags.ESSymbol)) {
+                if (!isTypeAnyOrAllConstituentTypesHaveKind(t, TypeFlags.NumberLike | TypeFlags.StringLike | TypeFlags.ESSymbol)) {
                     error(node, Diagnostics.A_computed_property_name_must_be_of_type_string_number_symbol_or_any);
                 }
                 else {

tests/baselines/reference/computedPropertyNames51_ES5.errors.txt

@@ -0,0 +1,15 @@
+tests/cases/conformance/es6/computedProperties/computedPropertyNames51_ES5.ts(5,9): error TS2464: A computed property name must be of type 'string', 'number', 'symbol', or 'any'.
+
+
+==== tests/cases/conformance/es6/computedProperties/computedPropertyNames51_ES5.ts (1 errors) ====
+    function f<T, K extends keyof T>() {
+        var t: T;
+        var k: K;
+        var v = {
+            [t]: 0,
+            ~~~
+!!! error TS2464: A computed property name must be of type 'string', 'number', 'symbol', or 'any'.
+            [k]: 1
+        };
+    }
+

tests/baselines/reference/computedPropertyNames51_ES5.js

@@ -0,0 +1,21 @@
+//// [computedPropertyNames51_ES5.ts]
+function f<T, K extends keyof T>() {
+    var t: T;
+    var k: K;
+    var v = {
+        [t]: 0,
+        [k]: 1
+    };
+}
+
+
+//// [computedPropertyNames51_ES5.js]
+function f() {
+    var t;
+    var k;
+    var v = (_a = {},
+        _a[t] = 0,
+        _a[k] = 1,
+        _a);
+    var _a;
+}

tests/baselines/reference/computedPropertyNames51_ES6.errors.txt

@@ -0,0 +1,15 @@
+tests/cases/conformance/es6/computedProperties/computedPropertyNames51_ES6.ts(5,9): error TS2464: A computed property name must be of type 'string', 'number', 'symbol', or 'any'.
+
+
+==== tests/cases/conformance/es6/computedProperties/computedPropertyNames51_ES6.ts (1 errors) ====
+    function f<T, K extends keyof T>() {
+        var t: T;
+        var k: K;
+        var v = {
+            [t]: 0,
+            ~~~
+!!! error TS2464: A computed property name must be of type 'string', 'number', 'symbol', or 'any'.
+            [k]: 1
+        };
+    }
+

tests/baselines/reference/computedPropertyNames51_ES6.js

@@ -0,0 +1,20 @@
+//// [computedPropertyNames51_ES6.ts]
+function f<T, K extends keyof T>() {
+    var t: T;
+    var k: K;
+    var v = {
+        [t]: 0,
+        [k]: 1
+    };
+}
+
+
+//// [computedPropertyNames51_ES6.js]
+function f() {
+    var t;
+    var k;
+    var v = {
+        [t]: 0,
+        [k]: 1
+    };
+}

tests/baselines/reference/computedPropertyNames8_ES5.errors.txt

@@ -1,8 +1,7 @@
 tests/cases/conformance/es6/computedProperties/computedPropertyNames8_ES5.ts(5,9): error TS2464: A computed property name must be of type 'string', 'number', 'symbol', or 'any'.
-tests/cases/conformance/es6/computedProperties/computedPropertyNames8_ES5.ts(6,9): error TS2464: A computed property name must be of type 'string', 'number', 'symbol', or 'any'.
 
 
-==== tests/cases/conformance/es6/computedProperties/computedPropertyNames8_ES5.ts (2 errors) ====
+==== tests/cases/conformance/es6/computedProperties/computedPropertyNames8_ES5.ts (1 errors) ====
     function f<T, U extends string>() {
         var t: T;
         var u: U;
@@ -11,7 +10,5 @@ tests/cases/conformance/es6/computedProperties/computedPropertyNames8_ES5.ts(6,9
             ~~~
 !!! error TS2464: A computed property name must be of type 'string', 'number', 'symbol', or 'any'.
             [u]: 1
-            ~~~
-!!! error TS2464: A computed property name must be of type 'string', 'number', 'symbol', or 'any'.
         };
     }

tests/baselines/reference/computedPropertyNames8_ES6.errors.txt

@@ -1,8 +1,7 @@
 tests/cases/conformance/es6/computedProperties/computedPropertyNames8_ES6.ts(5,9): error TS2464: A computed property name must be of type 'string', 'number', 'symbol', or 'any'.
-tests/cases/conformance/es6/computedProperties/computedPropertyNames8_ES6.ts(6,9): error TS2464: A computed property name must be of type 'string', 'number', 'symbol', or 'any'.
 
 
-==== tests/cases/conformance/es6/computedProperties/computedPropertyNames8_ES6.ts (2 errors) ====
+==== tests/cases/conformance/es6/computedProperties/computedPropertyNames8_ES6.ts (1 errors) ====
     function f<T, U extends string>() {
         var t: T;
         var u: U;
@@ -11,7 +10,5 @@ tests/cases/conformance/es6/computedProperties/computedPropertyNames8_ES6.ts(6,9
             ~~~
 !!! error TS2464: A computed property name must be of type 'string', 'number', 'symbol', or 'any'.
             [u]: 1
-            ~~~
-!!! error TS2464: A computed property name must be of type 'string', 'number', 'symbol', or 'any'.
         };
     }

tests/cases/conformance/es6/computedProperties/computedPropertyNames51_ES5.ts

@@ -0,0 +1,8 @@
+function f<T, K extends keyof T>() {
+    var t: T;
+    var k: K;
+    var v = {
+        [t]: 0,
+        [k]: 1
+    };
+}

tests/cases/conformance/es6/computedProperties/computedPropertyNames51_ES6.ts

@@ -0,0 +1,9 @@
+// @target: es6
+function f<T, K extends keyof T>() {
+    var t: T;
+    var k: K;
+    var v = {
+        [t]: 0,
+        [k]: 1
+    };
+}