New error message when table overwrites existing key definition

src/main/java/com/moandjiezana/toml/Results.java

@@ -21,6 +21,14 @@ class Results {
         .append(table)
         .append("]\n");
     }
+
+    public void tableDuplicatesKey(String table, AtomicInteger line) {
+      sb.append("Key already exists for table definition on line ")
+        .append(line.get())
+        .append(": [")
+        .append(table)
+        .append("]\n");
+    }
     
     void emptyImplicitTable(String table, int line) {
       sb.append("Invalid table definition due to empty implicit table name: ")
@@ -216,7 +224,11 @@ class Results {
       } else if (currentContainer.accepts(tablePart)) {
         startTable(tablePart, line);
       } else {
-        errors.duplicateTable(tableName, -1);
+        if (currentContainer.get(tablePart) instanceof Container) {
+          errors.duplicateTable(tableName, line.get());
+        } else {
+          errors.tableDuplicatesKey(tablePart, line);
+        }
         break;
       }
     }

src/test/java/com/moandjiezana/toml/ErrorMessagesTest.java

@@ -120,4 +120,11 @@ public class ErrorMessagesTest {
     
     new Toml().parse("k = [ 1,\n  1.1 ]");
   }
+  
+  @Test
+  public void should_fail_when_key_itn_root_is_overwritten_by_table() throws Exception {
+    e.expectMessage("Key already exists for table definition on line 2: [a]");
+    
+    new Toml().parse("a=1\n  [a]");
+  }
 }