Merge pull request #14616 from Microsoft/inferFromNestedArrowFunctionExpressionsAndPropDeclarations

Infer class property declarations from assignments in nested arrow functions

Author: mhegazy

src/compiler/binder.ts

@@ -2332,6 +2332,7 @@ namespace ts {
 
         function bindThisPropertyAssignment(node: BinaryExpression) {
             Debug.assert(isInJavaScriptFile(node));
+            const container = getThisContainer(node, /*includeArrowFunctions*/false);
             switch (container.kind) {
                 case SyntaxKind.FunctionDeclaration:
                 case SyntaxKind.FunctionExpression:
@@ -2342,6 +2343,7 @@ namespace ts {
                     break;
 
                 case SyntaxKind.Constructor:
+                case SyntaxKind.PropertyDeclaration:
                 case SyntaxKind.MethodDeclaration:
                 case SyntaxKind.GetAccessor:
                 case SyntaxKind.SetAccessor:

tests/baselines/reference/inferringClassMembersFromAssignments.js

@@ -20,6 +20,15 @@ class C {
             this.inMethod = "string"
         }
         this.inMultiple = "string";
+
+        var action = () => {
+            if (Math.random()) {
+                this.inNestedArrowFunction = 0;
+            }
+            else {
+                this.inNestedArrowFunction = "string"
+            }
+        };
     }
     get() {
         if (Math.random()) {
@@ -38,13 +47,30 @@ class C {
             this.inSetter = "string"
         }
     }
+    prop = () => {
+        if (Math.random()) {
+            this.inPropertyDeclaration = 0;
+        }
+        else {
+            this.inPropertyDeclaration = "string"
+        }
+    }
     static method() {
         if (Math.random()) {
             this.inStaticMethod = 0;
         }
         else {
             this.inStaticMethod = "string"
         }
+
+        var action = () => {
+            if (Math.random()) {
+                this.inStaticNestedArrowFunction = 0;
+            }
+            else {
+                this.inStaticNestedArrowFunction = "string"
+            }
+        };
     }
     static get() {
         if (Math.random()) {
@@ -62,6 +88,14 @@ class C {
             this.inStaticSetter = "string"
         }
     }
+    static prop = () => {
+        if (Math.random()) {
+            this.inStaticPropertyDeclaration = 0;
+        }
+        else {
+            this.inStaticPropertyDeclaration = "string"
+        }
+    }
 }
 
 //// [b.ts]
@@ -75,6 +109,8 @@ var stringOrNumberOrUndefined: string | number | undefined;
 var stringOrNumberOrUndefined = c.inMethod;
 var stringOrNumberOrUndefined = c.inGetter;
 var stringOrNumberOrUndefined = c.inSetter;
+var stringOrNumberOrUndefined = c.inPropertyDeclaration;
+var stringOrNumberOrUndefined = c.inNestedArrowFunction
 
 var stringOrNumberOrBoolean: string | number | boolean;
 
@@ -84,11 +120,23 @@ var stringOrNumberOrBoolean = c.inMultiple;
 var stringOrNumberOrUndefined = C.inStaticMethod;
 var stringOrNumberOrUndefined = C.inStaticGetter;
 var stringOrNumberOrUndefined = C.inStaticSetter;
+var stringOrNumberOrUndefined = C.inStaticPropertyDeclaration;
+var stringOrNumberOrUndefined = C.inStaticNestedArrowFunction;
 
 
 //// [output.js]
+var _this = this;
 var C = (function () {
     function C() {
+        var _this = this;
+        this.prop = function () {
+            if (Math.random()) {
+                _this.inPropertyDeclaration = 0;
+            }
+            else {
+                _this.inPropertyDeclaration = "string";
+            }
+        };
         if (Math.random()) {
             this.inConstructor = 0;
         }
@@ -98,13 +146,22 @@ var C = (function () {
         this.inMultiple = 0;
     }
     C.prototype.method = function () {
+        var _this = this;
         if (Math.random()) {
             this.inMethod = 0;
         }
         else {
             this.inMethod = "string";
         }
         this.inMultiple = "string";
+        var action = function () {
+            if (Math.random()) {
+                _this.inNestedArrowFunction = 0;
+            }
+            else {
+                _this.inNestedArrowFunction = "string";
+            }
+        };
     };
     C.prototype.get = function () {
         if (Math.random()) {
@@ -124,12 +181,21 @@ var C = (function () {
         }
     };
     C.method = function () {
+        var _this = this;
         if (Math.random()) {
             this.inStaticMethod = 0;
         }
         else {
             this.inStaticMethod = "string";
         }
+        var action = function () {
+            if (Math.random()) {
+                _this.inStaticNestedArrowFunction = 0;
+            }
+            else {
+                _this.inStaticNestedArrowFunction = "string";
+            }
+        };
     };
     C.get = function () {
         if (Math.random()) {
@@ -149,15 +215,27 @@ var C = (function () {
     };
     return C;
 }());
+C.prop = function () {
+    if (Math.random()) {
+        _this.inStaticPropertyDeclaration = 0;
+    }
+    else {
+        _this.inStaticPropertyDeclaration = "string";
+    }
+};
 var c = new C();
 var stringOrNumber;
 var stringOrNumber = c.inConstructor;
 var stringOrNumberOrUndefined;
 var stringOrNumberOrUndefined = c.inMethod;
 var stringOrNumberOrUndefined = c.inGetter;
 var stringOrNumberOrUndefined = c.inSetter;
+var stringOrNumberOrUndefined = c.inPropertyDeclaration;
+var stringOrNumberOrUndefined = c.inNestedArrowFunction;
 var stringOrNumberOrBoolean;
 var stringOrNumberOrBoolean = c.inMultiple;
 var stringOrNumberOrUndefined = C.inStaticMethod;
 var stringOrNumberOrUndefined = C.inStaticGetter;
 var stringOrNumberOrUndefined = C.inStaticSetter;
+var stringOrNumberOrUndefined = C.inStaticPropertyDeclaration;
+var stringOrNumberOrUndefined = C.inStaticNestedArrowFunction;