diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index fc79da502c8..7b5fd18920e 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -2843,7 +2843,7 @@ namespace ts {
             if (isBindingPattern(element.name)) {
                 return getTypeFromBindingPattern(<BindingPattern>element.name, includePatternInType);
             }
-            if (compilerOptions.noImplicitAny && canReportImplicitAnyError(element)) {
+            if (compilerOptions.noImplicitAny && !declarationBelongsToPrivateAmbientMember(element)) {
                 reportImplicitAnyError(element, anyType);
             }
             return anyType;
@@ -2936,16 +2936,17 @@ namespace ts {
 
             // Report implicit any errors unless this is a private property within an ambient declaration
             if (reportErrors && compilerOptions.noImplicitAny) {
-                if (canReportImplicitAnyError(declaration)) {
+                if (!declarationBelongsToPrivateAmbientMember(declaration)) {
                     reportImplicitAnyError(declaration, type);
                 }
             }
             return type;
         }
 
-        function canReportImplicitAnyError(declaration: VariableLikeDeclaration) {
+        function declarationBelongsToPrivateAmbientMember(declaration: VariableLikeDeclaration) {
             const root = getRootDeclaration(declaration);
-            return !isPrivateWithinAmbient(root) && !(root.kind === SyntaxKind.Parameter && isPrivateWithinAmbient(root.parent));
+            const memberDeclaration = root.kind === SyntaxKind.Parameter ? root.parent : root;
+            return isPrivateWithinAmbient(memberDeclaration);
         }
 
         function getTypeOfVariableOrParameterOrProperty(symbol: Symbol): Type {