Add structured coroutines and explicit error handling

internal/lang/references_test.go

@@ -0,0 +1,43 @@
+package lang
+
+import (
+	"strings"
+	"testing"
+)
+
+func TestGotlinClassesAreReferenceTypesByDefault(t *testing.T) {
+	prog, err := Parse(`package demo
+class Repository
+class Service(val repository: Repository)
+fun create(): Service { return Service(Repository()) }
+fun many(): List<Repository> { return listOf(Repository()) }
+fun optional(): Repository? { return null }`)
+	if err != nil {
+		t.Fatal(err)
+	}
+	out, err := GenerateGo(prog)
+	if err != nil {
+		t.Fatal(err)
+	}
+	for _, want := range []string{"repository *Repository", "func create() *Service", "func many() []*Repository", "func optional() *Repository"} {
+		if !strings.Contains(string(out), want) {
+			t.Fatalf("missing %q:\n%s", want, out)
+		}
+	}
+}
+
+func TestExplicitClassPointerRemainsCompatible(t *testing.T) {
+	prog, err := Parse(`package demo
+class Repository
+fun use(repository: *Repository): *Repository { return repository }`)
+	if err != nil {
+		t.Fatal(err)
+	}
+	out, err := GenerateGo(prog)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if strings.Contains(string(out), "**Repository") || !strings.Contains(string(out), "repository *Repository") {
+		t.Fatalf("unexpected explicit pointer output:\n%s", out)
+	}
+}