Use values from the first module when unifying modules.

Fixes #736

spec/errors/global_name_conflict

@@ -0,0 +1,47 @@
+module Main {
+  fun message() : String {
+    "Hello, world!"
+  }
+}
+
+component Main {
+  fun render : Html {
+    <div>"#{Main.message()}"</div>
+  }
+}
+--------------------------------------------------------------------------------
+░ ERROR (GLOBAL_NAME_CONFLICT) ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░
+
+There is already a module with the name: Main
+
+You are trying to define something with the same name here:
+
+    ┌ errors/global_name_conflict:7:1
+    ├───────────────────────────────────
+   3│     "Hello, world!"
+   4│   }
+   5│ }
+   6│
+    │ ⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄
+   7│ component Main {
+   8│   fun render : Html {
+   9│     <div>"#{Main.message()}"</div>
+  10│   }
+  11│ }
+    │ ⌃⌃⌃⌃⌃⌃⌃⌃⌃⌃⌃⌃⌃⌃⌃⌃⌃⌃⌃⌃⌃⌃⌃⌃⌃⌃⌃⌃⌃⌃⌃⌃⌃⌃
+
+The module is defined here:
+
+    ┌ errors/global_name_conflict:1:1
+    ├───────────────────────────────────
+    │ ⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄⌄
+   1│ module Main {
+   2│   fun message() : String {
+   3│     "Hello, world!"
+   4│   }
+   5│ }
+    │ ⌃⌃⌃⌃⌃⌃⌃⌃⌃⌃⌃⌃⌃⌃⌃⌃⌃⌃⌃⌃⌃⌃⌃⌃⌃⌃
+   6│
+   7│ component Main {
+   8│   fun render : Html {
+   9│     <div>"#{Main.message()}"</div>

src/ast.cr

@@ -82,13 +82,13 @@ module Mint
               # TODO: We may need to store each modules name node for
               # future features, but for now we just store the first
               comment: modules.compact_map(&.comment).first?,
-              file: Parser::File.new(contents: "", path: ""),
               functions: modules.flat_map(&.functions),
               constants: modules.flat_map(&.constants),
-              from: Parser::Location.new,
-              to: Parser::Location.new,
+              comments: modules.first.comments,
+              file: modules.first.file,
+              from: modules.first.from,
               name: modules.first.name,
-              comments: [] of Comment)
+              to: modules.first.to)
           end
 
       @unified_locales =