feat(go): preserve casing of enum member names (#2598)

As suggested in aws/aws-cdk-rfcs#292, using `_` to separate the constant
name from the type name, and preserving the constant's casing results in
an API that is slightly more readable, and less prone to namespace
collisions.

packages/@jsii/go-runtime/jsii-calc-test/main_test.go

@@ -159,20 +159,20 @@ func TestAllTypes(t *testing.T) {
 
 func TestEnumUnmarshal(t *testing.T) {
 	actual := calc.EnumDispenser_RandomStringLikeEnum()
-	if actual != calc.StringEnumB {
+	if actual != calc.StringEnum_B {
 		t.Errorf("Expected StringEnum.B. Actual: %s", actual)
 	}
 }
 
 func TestEnumRoundtrip(t *testing.T) {
 	allTypes := calc.NewAllTypes()
-	actual := allTypes.EnumMethod(calc.StringEnumA)
-	if actual != calc.StringEnumA {
+	actual := allTypes.EnumMethod(calc.StringEnum_A)
+	if actual != calc.StringEnum_A {
 		t.Errorf("Expected StringEnum.A. Actual: %s", actual)
 	}
 
-	actual = allTypes.EnumMethod(calc.StringEnumC)
-	if actual != calc.StringEnumC {
+	actual = allTypes.EnumMethod(calc.StringEnum_C)
+	if actual != calc.StringEnum_C {
 		t.Errorf("Expected StringEnum.C. Actual: %s", actual)
 	}
 }
@@ -184,9 +184,9 @@ func TestOptionalEnums(t *testing.T) {
 		t.Error("Expected value to be nil")
 	}
 
-	allTypes.SetOptionalEnumValue(calc.StringEnumB)
+	allTypes.SetOptionalEnumValue(calc.StringEnum_B)
 	actual = allTypes.GetOptionalEnumValue()
-	if actual != calc.StringEnumB {
+	if actual != calc.StringEnum_B {
 		t.Errorf("Expected StringEnum.B. Actual: %s", actual)
 	}
 

packages/jsii-pacmak/lib/targets/go/types/enum.ts

@@ -1,4 +1,4 @@
-import { CodeMaker, toPascalCase } from 'codemaker';
+import { CodeMaker } from 'codemaker';
 import { EnumType, EnumMember } from 'jsii-reflect';
 
 import { EmitContext } from '../emit-context';
@@ -59,7 +59,7 @@ class GoEnumMember {
   public readonly rawValue: string;
 
   public constructor(private readonly parent: Enum, entry: EnumMember) {
-    this.name = `${parent.name}${toPascalCase(entry.name)}`;
+    this.name = `${parent.name}_${entry.name}`;
     this.rawValue = entry.name;
   }