Disallow modifiers in object literal property assignment

Fixes bug #5994

src/compiler/checker.ts

@@ -15969,6 +15969,11 @@ namespace ts {
                     return grammarErrorOnNode((<ShorthandPropertyAssignment>prop).equalsToken, Diagnostics.can_only_be_used_in_an_object_literal_property_inside_a_destructuring_assignment);
                 }
 
+                // Modifiers cannot appear in property assignments
+                if (prop.modifiers && prop.modifiers.length > 0) {
+                    grammarErrorOnNode(prop.modifiers[0], Diagnostics.Modifiers_cannot_appear_here);
+                }
+
                 // ECMA-262 11.1.5 Object Initialiser
                 // If previous is not undefined then throw a SyntaxError exception if any of the following conditions are true
                 // a.This production is contained in strict code and IsDataDescriptor(previous) is true and

src/compiler/parser.ts

@@ -3981,6 +3981,7 @@ namespace ts {
             }
             else {
                 const propertyAssignment = <PropertyAssignment>createNode(SyntaxKind.PropertyAssignment, fullStart);
+                propertyAssignment.modifiers = modifiers;
                 propertyAssignment.name = propertyName;
                 propertyAssignment.questionToken = questionToken;
                 parseExpected(SyntaxKind.ColonToken);

tests/baselines/reference/modifiersInObjectLiterals.errors.txt

@@ -0,0 +1,24 @@
+tests/cases/compiler/modifiersInObjectLiterals.ts(2,2): error TS1184: Modifiers cannot appear here.
+tests/cases/compiler/modifiersInObjectLiterals.ts(3,2): error TS1184: Modifiers cannot appear here.
+tests/cases/compiler/modifiersInObjectLiterals.ts(4,2): error TS1184: Modifiers cannot appear here.
+tests/cases/compiler/modifiersInObjectLiterals.ts(5,2): error TS1184: Modifiers cannot appear here.
+
+
+==== tests/cases/compiler/modifiersInObjectLiterals.ts (4 errors) ====
+    let data = {
+    	public foo: 'hey',
+    	~~~~~~
+!!! error TS1184: Modifiers cannot appear here.
+    	private bar: 'nay',
+    	~~~~~~~
+!!! error TS1184: Modifiers cannot appear here.
+    	protected baz: 'oh my',
+    	~~~~~~~~~
+!!! error TS1184: Modifiers cannot appear here.
+    	abstract noWay: 'yes'	
+    	~~~~~~~~
+!!! error TS1184: Modifiers cannot appear here.
+    };
+    
+    data.foo + data.bar + data.baz + data.noWay
+    

tests/baselines/reference/modifiersInObjectLiterals.js

@@ -0,0 +1,19 @@
+//// [modifiersInObjectLiterals.ts]
+let data = {
+	public foo: 'hey',
+	private bar: 'nay',
+	protected baz: 'oh my',
+	abstract noWay: 'yes'	
+};
+
+data.foo + data.bar + data.baz + data.noWay
+
+
+//// [modifiersInObjectLiterals.js]
+var data = {
+    foo: 'hey',
+    bar: 'nay',
+    baz: 'oh my',
+    noWay: 'yes'
+};
+data.foo + data.bar + data.baz + data.noWay;

tests/cases/compiler/modifiersInObjectLiterals.ts

@@ -0,0 +1,8 @@
+let data = {
+	public foo: 'hey',
+	private bar: 'nay',
+	protected baz: 'oh my',
+	abstract noWay: 'yes'	
+};
+
+data.foo + data.bar + data.baz + data.noWay