@@ 89,6 89,10 @@ func mangle(unit *semantic.Unit) *nameResolver {
 			case *semantic.Struct:
 				b.withPrefixFor(decl)
 				names[decl] = b.get(decl.Ident())
+
+			case *semantic.Interface:
+				b.withPrefixFor(decl)
+				names[decl] = b.get(decl.Ident())
 			}
 		}
 		return true


@@ 208,6 212,12 @@ func (b *fmtBuilder) withPrefixFor(decl semantic.Decl) {
 		if !decl.Scope().IsTopLevel() {
 			b.withScope(decl.Scope())
 		}
+
+	case *semantic.Interface:
+		b.withExport(false)
+		if !decl.Scope().IsTopLevel() {
+			b.withScope(decl.Scope())
+		}
 	}
 }
 

@@ 0,0 1,21 @@
+interface I {
+  fn foo()
+}
+
+struct S {
+  let s: string
+
+  fn foo() {
+    println(s)
+  }
+}
+
+@extern(import: "fmt", symbol: "Println")
+fn println(s: string)
+
+fn main() {
+  let iface: I = S(s: "hello!")
+  iface.foo()
+}
+
+#=hello!

@@ 169,6 169,16 @@ func (t *translator) Visit(n semantic.Node) semantic.Visitor {
 			Specs: []goast.Spec{vs},
 		})
 
+	case *semantic.Interface:
+		if n.IsGeneric() {
+			// go nodes will be generated only on instantiation, create an empty container for now
+			m := &mark{list: t.topLevel, elem: t.topLevel.PushBack(newContainer(n))}
+			t.genDeclMarks[n] = m
+			break
+		}
+		name := t.resolver.NameForDecl(n)
+		t.createInterface(name, semantic.AsInterfaceType(n.Type()))
+
 		// ************** STATEMENTS *****************
 
 	case *semantic.Block: