fix(jsii): Defaulted parameters were not rendered as optional

packages/jsii-calc/lib/compliance.ts

@@ -240,6 +240,10 @@ export class RuntimeTypeChecking {
     public methodWithOptionalArguments(arg1: number, arg2: string, arg3?: Date) {
         arg1; arg2; arg3;
     }
+
+    public methodWithDefaultedArguments(arg1: number = 2, arg2: string, arg3: Date = new Date()) {
+        arg1; arg2; arg3;
+    }
 }
 
 export namespace DerivedClassHasNoProperties {
@@ -865,4 +869,4 @@ export class AbstractClassReturner {
             abstractProperty: 'hello-abstract-property'
         }
     }
-}
+}

packages/jsii-calc/test/assembly.jsii

@@ -2270,6 +2270,31 @@
       },
       "kind": "class",
       "methods": [
+        {
+          "name": "methodWithDefaultedArguments",
+          "parameters": [
+            {
+              "name": "arg1",
+              "type": {
+                "optional": true,
+                "primitive": "number"
+              }
+            },
+            {
+              "name": "arg2",
+              "type": {
+                "primitive": "string"
+              }
+            },
+            {
+              "name": "arg3",
+              "type": {
+                "optional": true,
+                "primitive": "date"
+              }
+            }
+          ]
+        },
         {
           "docs": {
             "comment": "Used to verify verification of number of method arguments."
@@ -3070,5 +3095,5 @@
     }
   },
   "version": "0.7.5",
-  "fingerprint": "XrmsNUcNdYiHEC6BRVT5XoeVmYQZzjYgiu6MyibgOwk="
+  "fingerprint": "Ywp3EW+cv1wVMiKbYcuDGIc5pIYI3RQtcVzwVBMg0aM="
 }

packages/jsii-pacmak/test/expected.jsii-calc/dotnet/Amazon.JSII.Tests.CalculatorPackageId/.jsii

@@ -2270,6 +2270,31 @@
       },
       "kind": "class",
       "methods": [
+        {
+          "name": "methodWithDefaultedArguments",
+          "parameters": [
+            {
+              "name": "arg1",
+              "type": {
+                "optional": true,
+                "primitive": "number"
+              }
+            },
+            {
+              "name": "arg2",
+              "type": {
+                "primitive": "string"
+              }
+            },
+            {
+              "name": "arg3",
+              "type": {
+                "optional": true,
+                "primitive": "date"
+              }
+            }
+          ]
+        },
         {
           "docs": {
             "comment": "Used to verify verification of number of method arguments."
@@ -3070,5 +3095,5 @@
     }
   },
   "version": "0.7.5",
-  "fingerprint": "XrmsNUcNdYiHEC6BRVT5XoeVmYQZzjYgiu6MyibgOwk="
+  "fingerprint": "Ywp3EW+cv1wVMiKbYcuDGIc5pIYI3RQtcVzwVBMg0aM="
 }

packages/jsii-pacmak/test/expected.jsii-calc/dotnet/Amazon.JSII.Tests.CalculatorPackageId/Amazon/JSII/Tests/CalculatorNamespace/RuntimeTypeChecking.cs

@@ -18,6 +18,12 @@ protected RuntimeTypeChecking(DeputyProps props): base(props)
         {
         }
 
+        [JsiiMethod("methodWithDefaultedArguments", null, "[{\"name\":\"arg1\",\"type\":{\"primitive\":\"number\",\"optional\":true}},{\"name\":\"arg2\",\"type\":{\"primitive\":\"string\"}},{\"name\":\"arg3\",\"type\":{\"primitive\":\"date\",\"optional\":true}}]")]
+        public virtual void MethodWithDefaultedArguments(double? arg1, string arg2, DateTime? arg3)
+        {
+            InvokeInstanceVoidMethod(new object[]{arg1, arg2, arg3});
+        }
+
         /// <summary>Used to verify verification of number of method arguments.</summary>
         [JsiiMethod("methodWithOptionalArguments", null, "[{\"name\":\"arg1\",\"type\":{\"primitive\":\"number\"}},{\"name\":\"arg2\",\"type\":{\"primitive\":\"string\"}},{\"name\":\"arg3\",\"type\":{\"primitive\":\"date\",\"optional\":true}}]")]
         public virtual void MethodWithOptionalArguments(double arg1, string arg2, DateTime? arg3)

packages/jsii-pacmak/test/expected.jsii-calc/java/src/main/java/software/amazon/jsii/tests/calculator/RuntimeTypeChecking.java

@@ -11,6 +11,14 @@ public RuntimeTypeChecking() {
         software.amazon.jsii.JsiiEngine.getInstance().createNewObject(this);
     }
 
+    public void methodWithDefaultedArguments(@javax.annotation.Nullable final java.lang.Number arg1, final java.lang.String arg2, @javax.annotation.Nullable final java.time.Instant arg3) {
+        this.jsiiCall("methodWithDefaultedArguments", Void.class, java.util.stream.Stream.concat(java.util.stream.Stream.concat(java.util.stream.Stream.of(arg1), java.util.stream.Stream.of(java.util.Objects.requireNonNull(arg2, "arg2 is required"))), java.util.stream.Stream.of(arg3)).toArray());
+    }
+
+    public void methodWithDefaultedArguments(@javax.annotation.Nullable final java.lang.Number arg1, final java.lang.String arg2) {
+        this.jsiiCall("methodWithDefaultedArguments", Void.class, java.util.stream.Stream.concat(java.util.stream.Stream.of(arg1), java.util.stream.Stream.of(java.util.Objects.requireNonNull(arg2, "arg2 is required"))).toArray());
+    }
+
     /**
      * Used to verify verification of number of method arguments.
      */

packages/jsii-pacmak/test/expected.jsii-calc/sphinx/jsii-calc.rst

@@ -2417,6 +2417,16 @@ RuntimeTypeChecking
 
 
 
+   .. py:method:: methodWithDefaultedArguments([arg1, arg2, [arg3]])
+
+      :param arg1: 
+      :type arg1: number or undefined
+      :param arg2: 
+      :type arg2: string
+      :param arg3: 
+      :type arg3: date or undefined
+
+
    .. py:method:: methodWithOptionalArguments(arg1, arg2, [arg3])
 
       Used to verify verification of number of method arguments.

packages/jsii/lib/assembler.ts

@@ -618,14 +618,18 @@ export class Assembler implements Emitter {
         if (LOG.isTraceEnabled()) {
             LOG.trace(`Processing parameter: ${colors.cyan(paramSymbol.name)}`);
         }
+        const paramDeclaration = paramSymbol.valueDeclaration as ts.ParameterDeclaration;
         const parameter: spec.Parameter = {
             name: paramSymbol.name,
             type: await this._typeReference(this._typeChecker.getTypeAtLocation(paramSymbol.valueDeclaration), paramSymbol.valueDeclaration),
-            variadic: !!(paramSymbol.valueDeclaration as ts.ParameterDeclaration).dotDotDotToken
+            variadic: !!paramDeclaration.dotDotDotToken
         };
         if (parameter.variadic) {
             parameter.type = (parameter.type as spec.CollectionTypeReference).collection.elementtype;
         }
+        if (paramDeclaration.initializer != null) {
+            parameter.type.optional = true;
+        }
         this._visitDocumentation(paramSymbol, parameter);
         return parameter;
     }