eval: Isolate global ns of modules.

This fixes #590.

eval/builtin_special.go

@@ -295,7 +295,7 @@ func loadModule(fm *Frame, name string) (Ns, error) {
 		0, len(src.code), fm.addTraceback(), false,
 	}
 
-	op, err := newFm.Compile(n, src)
+	op, err := compile(newFm.Builtin.static(), modGlobal.static(), n, src)
 	if err != nil {
 		return nil, err
 	}

eval/builtin_special_test.go

@@ -39,7 +39,7 @@ var builtinSpecialTests = []Test{
 	// return.
 	{"fn f []{ put a; return; put b }; f", want{out: strs("a")}},
 
-	// Modules (see setup_datadir_test.go for setup)
+	// Modules (see testmain_test.go for setup)
 	// "use" imports a module.
 	{`use lorem; put $lorem:name`, want{out: strs("lorem")}},
 	// imports are lexically scoped
@@ -61,6 +61,9 @@ var builtinSpecialTests = []Test{
 	// relative uses
 	{`use a/b/c/x; put $x:d $x:lorem`, want{out: strs("a/b/c/d", "lorem")}},
 
+	// Variables defined in the default global scope is invisible from modules
+	NewTest("x = foo; use put-x").WantAnyErr(),
+
 	// TODO: Test module namespace
 }
 

eval/eval.go

@@ -206,7 +206,7 @@ func (ev *Evaler) eval(op Op, ports []*Port, src *Source) error {
 	return ec.Eval(op)
 }
 
-// Compile compiles elvish code in the global scope. If the error is not nil, it
+// Compile compiles Elvish code in the global scope. If the error is not nil, it
 // always has type CompilationError.
 func (ev *Evaler) Compile(n *parse.Chunk, src *Source) (Op, error) {
 	return compile(ev.Builtin.static(), ev.Global.static(), n, src)

eval/testmain_test.go

@@ -68,6 +68,7 @@ var mods = map[string]string{
 	"a/b/c/d":  "name = a/b/c/d",
 	"a/b/c/x":  "use ./d; d = $d:name; use ../../../lorem; lorem = $lorem:name",
 	"has/init": "put has/init",
+	"put-x":    "put $x",
 }
 
 var libDir string