interp: make use of type constructors

It was initially assumed that `nodeType` needed to rebuild the type from scratch, but this is not the case anymore. The existing type constructors are now used in `nodeType` to make it more readable. In doing this some bugs in type strings were found and fixed, along with adding the real package name to the type.

As `ptrOf` is now the only place that pointer types are constructed, it is feasible to cache the pointer type on the value type. To ensures that we have a consistent pointer type for any value type.

interp/gta.go

@@ -11,7 +11,7 @@ import (
 // All function bodies are skipped. GTA is necessary to handle out of
 // order declarations and multiple source files packages.
 // rpath is the relative path to the directory containing the source for the package.
-func (interp *Interpreter) gta(root *node, rpath, importPath string) ([]*node, error) {
+func (interp *Interpreter) gta(root *node, rpath, importPath, pkgName string) ([]*node, error) {
 	sc := interp.initScopePkg(importPath)
 	var err error
 	var revisit []*node
@@ -266,14 +266,14 @@ func (interp *Interpreter) gta(root *node, rpath, importPath string) ([]*node, e
 
 			switch n.child[1].kind {
 			case identExpr, selectorExpr:
-				n.typ = namedOf(typ, importPath, typeName, withNode(n.child[0]), withScope(sc))
+				n.typ = namedOf(typ, pkgName, typeName, withNode(n.child[0]), withScope(sc))
 				n.typ.incomplete = typ.incomplete
 				n.typ.field = typ.field
 				copy(n.typ.method, typ.method)
 			default:
 				n.typ = typ
 				n.typ.name = typeName
-				n.typ.path = importPath
+				n.typ.path = pkgName
 			}
 			n.typ.str = n.typ.path + "." + n.typ.name
 
@@ -312,11 +312,11 @@ func (interp *Interpreter) gta(root *node, rpath, importPath string) ([]*node, e
 }
 
 // gtaRetry (re)applies gta until all global constants and types are defined.
-func (interp *Interpreter) gtaRetry(nodes []*node, importPath string) error {
+func (interp *Interpreter) gtaRetry(nodes []*node, importPath, pkgName string) error {
 	revisit := []*node{}
 	for {
 		for _, n := range nodes {
-			list, err := interp.gta(n, importPath, importPath)
+			list, err := interp.gta(n, importPath, importPath, pkgName)
 			if err != nil {
 				return err
 			}

interp/interp.go

@@ -537,7 +537,7 @@ func (interp *Interpreter) eval(src, name string, inc bool) (res reflect.Value,
 	}
 
 	// Perform global types analysis.
-	if err = interp.gtaRetry([]*node{root}, pkgName); err != nil {
+	if err = interp.gtaRetry([]*node{root}, pkgName, pkgName); err != nil {
 		return res, err
 	}
 

interp/src.go

@@ -97,7 +97,7 @@ func (interp *Interpreter) importSrc(rPath, importPath string, skipTest bool) (s
 
 		subRPath := effectivePkg(rPath, importPath)
 		var list []*node
-		list, err = interp.gta(root, subRPath, importPath)
+		list, err = interp.gta(root, subRPath, importPath, pkgName)
 		if err != nil {
 			return "", err
 		}
@@ -106,7 +106,7 @@ func (interp *Interpreter) importSrc(rPath, importPath string, skipTest bool) (s
 
 	// Revisit incomplete nodes where GTA could not complete.
 	for _, nodes := range revisit {
-		if err = interp.gtaRetry(nodes, importPath); err != nil {
+		if err = interp.gtaRetry(nodes, importPath, pkgName); err != nil {
 			return "", err
 		}
 	}

interp/type.go

@@ -118,6 +118,7 @@ type itype struct {
 	recv        *itype        // Receiver type for funcT or nil
 	arg         []*itype      // Argument types if funcT or nil
 	ret         []*itype      // Return types if funcT or nil
+	ptr         *itype        // Pointer to this type. Might be nil
 	method      []*node       // Associated methods or nil
 	name        string        // name of type within its package for a defined type
 	path        string        // for a defined type, the package import path
@@ -215,10 +216,14 @@ func wrapperValueTOf(rtype reflect.Type, val *itype, opts ...itypeOption) *itype
 
 // ptrOf returns a pointer to t.
 func ptrOf(val *itype, opts ...itypeOption) *itype {
+	if val.ptr != nil {
+		return val.ptr
+	}
 	t := &itype{cat: ptrT, val: val, str: "*" + val.str}
 	for _, opt := range opts {
 		opt(t)
 	}
+	val.ptr = t
 	return t
 }
 
@@ -255,7 +260,7 @@ func chanOf(val *itype, dir chanDir, opts ...itypeOption) *itype {
 		cat = chanRecvT
 		str = "<-chan "
 	}
-	t := &itype{cat: cat, val: val, str: str}
+	t := &itype{cat: cat, val: val, str: str + val.str}
 	for _, opt := range opts {
 		opt(t)
 	}
@@ -298,25 +303,22 @@ func nodeType(interp *Interpreter, sc *scope, n *node) (*itype, error) {
 	var err error
 	switch n.kind {
 	case addressExpr, starExpr:
-		t.cat = ptrT
+		val, err := nodeType(interp, sc, n.child[0])
-		if t.val, err = nodeType(interp, sc, n.child[0]); err != nil {
+		if err != nil {
 			return nil, err
 		}
-		repr.WriteString("*" + t.val.str)
+		t = ptrOf(val, withNode(n), withScope(sc))
-		t.incomplete = t.val.incomplete
+		t.incomplete = val.incomplete
 
 	case arrayType:
 		c0 := n.child[0]
 		if len(n.child) == 1 {
-			// Array size is not defined.
+			val, err := nodeType(interp, sc, c0)
-			t.cat = sliceT
+			if err != nil {
-			if t.val, err = nodeType(interp, sc, c0); err != nil {
 				return nil, err
 			}
-			t.incomplete = t.val.incomplete
+			t = sliceOf(val, withNode(n), withScope(sc))
-			if t.val != nil {
+			t.incomplete = val.incomplete
-				repr.WriteString("[]" + t.val.str)
-			}
 			break
 		}
 		// Array size is defined.
@@ -526,29 +528,20 @@ func nodeType(interp *Interpreter, sc *scope, n *node) (*itype, error) {
 	case compositeLitExpr:
 		t, err = nodeType(interp, sc, n.child[0])
 
-	case chanType:
+	case chanType, chanTypeRecv, chanTypeSend:
-		t.cat = chanT
+		dir := chanSendRecv
-		if t.val, err = nodeType(interp, sc, n.child[0]); err != nil {
+		switch n.kind {
-			return nil, err
-		}
-		repr.WriteString("chan " + t.val.str)
-		t.incomplete = t.val.incomplete
-
 		case chanTypeRecv:
-		t.cat = chanRecvT
+			dir = chanRecv
-		if t.val, err = nodeType(interp, sc, n.child[0]); err != nil {
-			return nil, err
-		}
-		repr.WriteString("<-chan " + t.val.str)
-		t.incomplete = t.val.incomplete
-
 		case chanTypeSend:
-		t.cat = chanSendT
+			dir = chanSend
-		if t.val, err = nodeType(interp, sc, n.child[0]); err != nil {
+		}
+		val, err := nodeType(interp, sc, n.child[0])
+		if err != nil {
 			return nil, err
 		}
-		repr.WriteString("chan<- " + t.val.str)
+		t = chanOf(val, dir, withNode(n), withScope(sc))
-		t.incomplete = t.val.incomplete
+		t.incomplete = val.incomplete
 
 	case ellipsisExpr:
 		t.cat = variadicT
@@ -690,7 +683,6 @@ func nodeType(interp *Interpreter, sc *scope, n *node) (*itype, error) {
 				return nil, err
 			}
 			t.field = append(t.field, structField{name: f0.ident, typ: typ})
-			repr.WriteString(" " + f0.ident + typ.str[4:])
 			incomplete = incomplete || typ.incomplete
 		}
 		methStr := methodsTypeString(t.field)