fix: apply automatic type conversion to constant expressions (#484)

CONTRIBUTING.md

@@ -13,7 +13,12 @@ discussions.
 Once the proposal is approved, a Pull Request can be opened. If you want
 to provide early visibility to reviewers, create a [Draft Pull Request].
 
+We will also require you to sign the [Containous Contributor License Agreement]
+after you submit your first pull request to this project. The link to sign the
+agreement will be presented to you in the web interface of the pull request.
+
 [Issues]: https://github.com/containous/yaegi/issues
 [Pull Requests]: https://github.com/containous/yaegi/issues
 [Feature Request]: https://github.com/containous/yaegi/issues/new?template=feature_request.md
 [Draft Pull Request]: https://github.blog/2019-02-14-introducing-draft-pull-requests/
+[Containous Contributor License Agreement]: https://cla-assistant.io/containous/yaegi

_test/bin2.go

@@ -0,0 +1,13 @@
+package main
+
+import (
+	"fmt"
+	"math"
+)
+
+func main() {
+	fmt.Println(math.Abs(-5))
+}
+
+// Output:
+// 5

_test/foo-bar/foo-bar.go

@@ -0,0 +1,3 @@
+package bar
+
+var Name = "foo-bar"

_test/import7.go

@@ -0,0 +1,10 @@
+package main
+
+import "github.com/containous/yaegi/_test/foo-bar"
+
+func main() {
+	println(bar.Name)
+}
+
+// Output:
+// foo-bar

_test/interface14.go

@@ -0,0 +1,17 @@
+package main
+
+type T struct{}
+
+func (t *T) Error() string { return "T: error" }
+
+var invalidT = &T{}
+
+func main() {
+	var err error
+	if err != invalidT {
+		println("ok")
+	}
+}
+
+// Output:
+// ok

_test/interface15.go

@@ -0,0 +1,28 @@
+package main
+
+type Fooer interface {
+	Foo() string
+}
+
+type Barer interface {
+	//fmt.Stringer
+	Fooer
+	Bar()
+}
+
+type T struct{}
+
+func (t *T) Foo() string { return "T: foo" }
+func (*T) Bar()          { println("in bar") }
+
+var t = &T{}
+
+func main() {
+	var f Barer
+	if f != t {
+		println("ok")
+	}
+}
+
+// Output:
+// ok

_test/interface16.go

@@ -0,0 +1,25 @@
+package main
+
+import "fmt"
+
+type Barer interface {
+	fmt.Stringer
+	Bar()
+}
+
+type T struct{}
+
+func (*T) String() string { return "T: nothing" }
+func (*T) Bar()           { println("in bar") }
+
+var t = &T{}
+
+func main() {
+	var f Barer
+	if f != t {
+		println("ok")
+	}
+}
+
+// Output:
+// ok

_test/interface17.go

@@ -0,0 +1,17 @@
+package main
+
+type T struct{}
+
+func (t T) Error() string { return "T: error" }
+
+var invalidT = T{}
+
+func main() {
+	var err error
+	if err != invalidT {
+		println("ok")
+	}
+}
+
+// Output:
+// ok

_test/interface18.go

@@ -0,0 +1,18 @@
+package main
+
+type T struct{}
+
+func (t *T) Error() string { return "T: error" }
+func (*T) Foo()            { println("foo") }
+
+var invalidT = &T{}
+
+func main() {
+	var err error
+	if err != invalidT {
+		println("ok")
+	}
+}
+
+// Output:
+// ok

_test/nil0.go

@@ -0,0 +1,15 @@
+package main
+
+import "fmt"
+
+func f() (host, port string, err error) {
+	return "", "", nil
+}
+
+func main() {
+	h, p, err := f()
+	fmt.Println(h, p, err)
+}
+
+// Output:
+//   <nil>

_test/nil1.go

@@ -0,0 +1,12 @@
+package main
+
+func main() {
+	var a error = nil
+
+	if a == nil || a.Error() == "nil" {
+		println("a is nil")
+	}
+}
+
+// Output:
+// a is nil

_test/or0.go

@@ -0,0 +1,9 @@
+package main
+
+func main() {
+	c := false
+	println(c || !c)
+}
+
+// Output:
+// true

_test/or1.go

@@ -0,0 +1,9 @@
+package main
+
+func main() {
+	c := false
+	println(!c || c)
+}
+
+// Output:
+// true

_test/str4.go

@@ -0,0 +1,11 @@
+package main
+
+import "unicode/utf8"
+
+func main() {
+	r, _ := utf8.DecodeRuneInString("Hello")
+	println(r < utf8.RuneSelf)
+}
+
+// Output:
+// true

_test/struct29.go

@@ -0,0 +1,19 @@
+package main
+
+type T1 struct {
+	A []T2
+	B []T2
+}
+
+type T2 struct {
+	name string
+}
+
+var t = T1{}
+
+func main() {
+	println("ok")
+}
+
+// Output:
+// ok

_test/struct30.go

@@ -0,0 +1,19 @@
+package main
+
+type T1 struct {
+	A []T2
+	M map[uint64]T2
+}
+
+type T2 struct {
+	name string
+}
+
+var t = T1{}
+
+func main() {
+	println("ok")
+}
+
+// Output:
+// ok

_test/switch22.go

@@ -0,0 +1,21 @@
+package main
+
+type T struct {
+	Name string
+}
+
+func f(t interface{}) {
+	switch ext := t.(type) {
+	case *T:
+		println("*T", ext.Name)
+	default:
+		println("unknown")
+	}
+}
+
+func main() {
+	f(&T{"truc"})
+}
+
+// Output:
+// *T truc

_test/time11.go

@@ -0,0 +1,15 @@
+package main
+
+import (
+	"fmt"
+	"time"
+)
+
+const df = time.Minute * 30
+
+func main() {
+	fmt.Printf("df: %v %T\n", df, df)
+}
+
+// Output:
+// df: 30m0s time.Duration

internal/genop/genop.go

@@ -352,6 +352,30 @@ func {{$name}}(n *node) {
 	}
 }
 {{end}}
+{{range $name, $op := .Unary}}
+func {{$name}}Const(n *node) {
+	t := n.typ.rtype
+	v := n.child[0].rval
+	n.rval = reflect.New(t).Elem()
+
+	{{- if $op.Bool}}
+	n.rval.SetBool({{$op.Name}} v.Bool())
+	{{- else}}
+	switch t.Kind() {
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		n.rval.SetInt({{$op.Name}} v.Int())
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
+		n.rval.SetUint({{$op.Name}} v.Uint())
+	{{- if $op.Float}}
+	case reflect.Float32, reflect.Float64:
+		n.rval.SetFloat({{$op.Name}} v.Float())
+	case reflect.Complex64, reflect.Complex128:
+		n.rval.SetComplex({{$op.Name}} v.Complex())
+	{{- end}}
+	}
+	{{- end}}
+}
+{{end}}
 {{range $name, $op := .Comparison}}
 func {{$name}}(n *node) {
 	tnext := getExec(n.tnext)
@@ -793,6 +817,7 @@ type Op struct {
 	Float   bool   // true if operator applies to float
 	Complex bool   // true if operator applies to complex
 	Shift   bool   // true if operator is a shift operation
+	Bool    bool   // true if operator applies to bool
 }
 
 func main() {
@@ -805,17 +830,17 @@ func main() {
 	b := &bytes.Buffer{}
 	data := map[string]interface{}{
 		"Arithmetic": map[string]Op{
-			"add":    {"+", true, true, true, false},
+			"add":    {"+", true, true, true, false, false},
-			"sub":    {"-", false, true, true, false},
+			"sub":    {"-", false, true, true, false, false},
-			"mul":    {"*", false, true, true, false},
+			"mul":    {"*", false, true, true, false, false},
-			"quo":    {"/", false, true, true, false},
+			"quo":    {"/", false, true, true, false, false},
-			"rem":    {"%", false, false, false, false},
+			"rem":    {"%", false, false, false, false, false},
-			"shl":    {"<<", false, false, false, true},
+			"shl":    {"<<", false, false, false, true, false},
-			"shr":    {">>", false, false, false, true},
+			"shr":    {">>", false, false, false, true, false},
-			"and":    {"&", false, false, false, false},
+			"and":    {"&", false, false, false, false, false},
-			"or":     {"|", false, false, false, false},
+			"or":     {"|", false, false, false, false, false},
-			"xor":    {"^", false, false, false, false},
+			"xor":    {"^", false, false, false, false, false},
-			"andNot": {"&^", false, false, false, false},
+			"andNot": {"&^", false, false, false, false, false},
 		},
 		"IncDec": map[string]Op{
 			"inc": {Name: "+"},
@@ -829,6 +854,12 @@ func main() {
 			"lowerEqual":   {Name: "<=", Complex: false},
 			"notEqual":     {Name: "!=", Complex: true},
 		},
+		"Unary": map[string]Op{
+			"not":    {Name: "!", Float: false, Bool: true},
+			"neg":    {Name: "-", Float: true, Bool: false},
+			"pos":    {Name: "+", Float: true, Bool: false},
+			"bitNot": {Name: "^", Float: false, Bool: false},
+		},
 	}
 	if err = parse.Execute(b, data); err != nil {
 		log.Fatal(err)

interp/ast.go

@@ -199,6 +199,7 @@ const (
 	aAndAssign
 	aAndNot
 	aAndNotAssign
+	aBitNot
 	aCall
 	aCase
 	aCompositeLit
@@ -217,11 +218,12 @@ const (
 	aMethod
 	aMul
 	aMulAssign
-	aNegate
+	aNeg
 	aNot
 	aNotEqual
 	aOr
 	aOrAssign
+	aPos
 	aQuo
 	aQuoAssign
 	aRange
@@ -255,6 +257,7 @@ var actions = [...]string{
 	aAndAssign:    "&=",
 	aAndNot:       "&^",
 	aAndNotAssign: "&^=",
+	aBitNot:       "^",
 	aCall:         "call",
 	aCase:         "case",
 	aCompositeLit: "compositeLit",
@@ -271,11 +274,12 @@ var actions = [...]string{
 	aMethod:       "Method",
 	aMul:          "*",
 	aMulAssign:    "*=",
-	aNegate:       "-",
+	aNeg:          "-",
 	aNot:          "!",
 	aNotEqual:     "!=",
 	aOr:           "|",
 	aOrAssign:     "|=",
+	aPos:          "+",
 	aQuo:          "/",
 	aQuoAssign:    "/=",
 	aRange:        "range",
@@ -771,6 +775,8 @@ func (interp *Interpreter) ast(src, name string) (string, *node, error) {
 			var kind = unaryExpr
 			var act action
 			switch a.Op {
+			case token.ADD:
+				act = aPos
 			case token.AND:
 				kind = addressExpr
 				act = aAddr
@@ -779,7 +785,9 @@ func (interp *Interpreter) ast(src, name string) (string, *node, error) {
 			case token.NOT:
 				act = aNot
 			case token.SUB:
-				act = aNegate
+				act = aNeg
+			case token.XOR:
+				act = aBitNot
 			}
 			st.push(addChild(&root, anc, pos, kind, act), nod)
 

interp/cfg.go

@@ -4,8 +4,8 @@ import (
 	"fmt"
 	"log"
 	"math"
-	"path"
 	"reflect"
+	"regexp"
 	"unicode"
 )
 
@@ -24,6 +24,10 @@ var constOp = map[action]func(*node){
 	aShr:    shrConst,
 	aAndNot: andNotConst,
 	aXor:    xorConst,
+	aNot:    notConst,
+	aBitNot: bitNotConst,
+	aNeg:    negConst,
+	aPos:    posConst,
 }
 
 var constBltn = map[string]func(*node){
@@ -32,6 +36,8 @@ var constBltn = map[string]func(*node){
 	"real":    realConst,
 }
 
+var identifier = regexp.MustCompile(`([\pL_][\pL_\d]*)$`)
+
 // cfg generates a control flow graph (CFG) from AST (wiring successors in AST)
 // and pre-compute frame sizes and indexes for all un-named (temporary) and named
 // variables. A list of nodes of init functions is returned.
@@ -170,23 +176,21 @@ func (interp *Interpreter) cfg(root *node) ([]*node, error) {
 				var typ *itype
 				if len(n.child) == 2 {
 					// 1 type in clause: define the var with this type in the case clause scope
-					switch sym, _, ok := sc.lookup(n.child[0].ident); {
+					switch {
-					case ok && sym.kind == typeSym:
-						typ = sym.typ
-					case n.child[0].kind == selectorExpr:
-						if typ, err = nodeType(interp, sc, n.child[0]); err != nil {
-							return false
-						}
 					case n.child[0].ident == "nil":
 						typ = sc.getType("interface{}")
-					default:
+					case !n.child[0].isType(sc):
 						err = n.cfgErrorf("%s is not a type", n.child[0].ident)
-						return false
+					default:
+						typ, err = nodeType(interp, sc, n.child[0])
 					}
 				} else {
 					// define the var with the type in the switch guard expression
 					typ = sn.child[1].child[1].child[0].typ
 				}
+				if err != nil {
+					return false
+				}
 				nod := n.lastChild().child[0]
 				index := sc.add(typ)
 				sc.sym[nod.ident] = &symbol{index: index, kind: varSym, typ: typ}
@@ -318,7 +322,7 @@ func (interp *Interpreter) cfg(root *node) ([]*node, error) {
 				name = n.child[0].ident
 			} else {
 				ipath = n.child[0].rval.String()
-				name = path.Base(ipath)
+				name = identifier.FindString(ipath)
 			}
 			if interp.binPkg[ipath] != nil && name != "." {
 				sc.sym[name] = &symbol{kind: pkgSym, typ: &itype{cat: binPkgT, path: ipath}}
@@ -549,7 +553,7 @@ func (interp *Interpreter) cfg(root *node) ([]*node, error) {
 			t0, t1 := c0.typ.TypeOf(), c1.typ.TypeOf()
 			// Shift operator type is inherited from first parameter only
 			// All other binary operators require both parameter types to be the same
-			if !isShiftNode(n) && !c0.typ.untyped && !c1.typ.untyped && c0.typ.id() != c1.typ.id() {
+			if !isShiftNode(n) && !c0.typ.untyped && !c1.typ.untyped && !c0.typ.equals(c1.typ) {
 				err = n.cfgErrorf("mismatched types %s and %s", c0.typ.id(), c1.typ.id())
 				break
 			}
@@ -602,8 +606,6 @@ func (interp *Interpreter) cfg(root *node) ([]*node, error) {
 				constOp[n.action](n)
 			}
 			switch {
-			//case n.typ != nil && n.typ.cat == BoolT && isAncBranch(n):
-			//	n.findex = -1
 			case n.rval.IsValid():
 				n.gen = nop
 				n.findex = -1
@@ -1021,6 +1023,9 @@ func (interp *Interpreter) cfg(root *node) ([]*node, error) {
 			n.child[1].tnext = n
 			n.typ = n.child[0].typ
 			n.findex = sc.add(n.typ)
+			if n.start.action == aNop {
+				n.start.gen = branch
+			}
 
 		case lorExpr:
 			n.start = n.child[0].start
@@ -1029,6 +1034,9 @@ func (interp *Interpreter) cfg(root *node) ([]*node, error) {
 			n.child[1].tnext = n
 			n.typ = n.child[0].typ
 			n.findex = sc.add(n.typ)
+			if n.start.action == aNop {
+				n.start.gen = branch
+			}
 
 		case parenExpr:
 			wireChild(n)
@@ -1068,7 +1076,7 @@ func (interp *Interpreter) cfg(root *node) ([]*node, error) {
 					// nil: Set node value to zero of return type
 					f := sc.def
 					var typ *itype
-					if typ, err = nodeType(interp, sc, f.child[2].child[1].child[i].lastChild()); err != nil {
+					if typ, err = nodeType(interp, sc, f.child[2].child[1].fieldType(i)); err != nil {
 						return
 					}
 					if typ.cat == funcT {
@@ -1155,7 +1163,7 @@ func (interp *Interpreter) cfg(root *node) ([]*node, error) {
 						n.typ = &itype{cat: valueT, rtype: s.Type().Elem()}
 					} else {
 						n.kind = rvalueExpr
-						n.typ = &itype{cat: valueT, rtype: s.Type()}
+						n.typ = &itype{cat: valueT, rtype: s.Type(), untyped: isValueUntyped(s)}
 						n.rval = s
 					}
 					n.gen = nop
@@ -1377,16 +1385,60 @@ func (interp *Interpreter) cfg(root *node) ([]*node, error) {
 		case unaryExpr:
 			wireChild(n)
 			n.typ = n.child[0].typ
-			if n.action == aRecv {
+			switch n.action {
+			case aRecv:
 				// Channel receive operation: set type to the channel data type
 				if n.typ.cat == valueT {
 					n.typ = &itype{cat: valueT, rtype: n.typ.rtype.Elem()}
 				} else {
 					n.typ = n.typ.val
 				}
+			case aBitNot:
+				if !isInt(n.typ.TypeOf()) {
+					err = n.cfgErrorf("illegal operand type for '^' operator")
+					return
+				}
+			case aNot:
+				if !isBool(n.typ) {
+					err = n.cfgErrorf("illegal operand type for '!' operator")
+					return
+				}
+			case aNeg, aPos:
+				if !isNumber(n.typ.TypeOf()) {
+					err = n.cfgErrorf("illegal operand type for '%v' operator", n.action)
+					return
+				}
 			}
 			// TODO: Optimisation: avoid allocation if boolean branch op (i.e. '!' in an 'if' expr)
-			n.findex = sc.add(n.typ)
+			if n.child[0].rval.IsValid() && constOp[n.action] != nil {
+				if n.typ == nil {
+					if n.typ, err = nodeType(interp, sc, n); err != nil {
+						return
+					}
+				}
+				n.typ.TypeOf() // init reflect type
+				constOp[n.action](n)
+			}
+			switch {
+			case n.rval.IsValid():
+				n.gen = nop
+				n.findex = -1
+			case n.anc.kind == assignStmt && n.anc.action == aAssign:
+				dest := n.anc.child[childPos(n)-n.anc.nright]
+				n.typ = dest.typ
+				n.findex = dest.findex
+			case n.anc.kind == returnStmt:
+				pos := childPos(n)
+				n.typ = sc.def.typ.ret[pos]
+				n.findex = pos
+			default:
+				if n.typ == nil {
+					if n.typ, err = nodeType(interp, sc, n); err != nil {
+						return
+					}
+				}
+				n.findex = sc.add(n.typ)
+			}
 
 		case valueSpec:
 			n.gen = reset
@@ -1528,7 +1580,7 @@ func isBinType(v reflect.Value) bool { return v.IsValid() && v.Kind() == reflect
 // isType returns true if node refers to a type definition, false otherwise
 func (n *node) isType(sc *scope) bool {
 	switch n.kind {
-	case arrayType, chanType, funcType, mapType, structType, rtypeExpr:
+	case arrayType, chanType, funcType, interfaceType, mapType, structType, rtypeExpr:
 		return true
 	case parenExpr, starExpr:
 		if len(n.child) == 1 {
@@ -1536,7 +1588,7 @@ func (n *node) isType(sc *scope) bool {
 		}
 	case selectorExpr:
 		pkg, name := n.child[0].ident, n.child[1].ident
-		if sym, _, ok := sc.lookup(pkg); ok {
+		if sym, _, ok := sc.lookup(pkg); ok && sym.kind == pkgSym {
 			path := sym.typ.path
 			if p, ok := n.interp.binPkg[path]; ok && isBinType(p[name]) {
 				return true // Imported binary type
@@ -1643,6 +1695,29 @@ func (n *node) isNatural() bool {
 	return false
 }
 
+// fieldType returns the nth parameter field node (type) of a fieldList node
+func (n *node) fieldType(m int) *node {
+	k := 0
+	l := len(n.child)
+	for i := 0; i < l; i++ {
+		cl := len(n.child[i].child)
+		if cl < 2 {
+			if k == m {
+				return n.child[i].lastChild()
+			}
+			k++
+			continue
+		}
+		for j := 0; j < cl-1; j++ {
+			if k == m {
+				return n.child[i].lastChild()
+			}
+			k++
+		}
+	}
+	return nil
+}
+
 // lastChild returns the last child of a node
 func (n *node) lastChild() *node { return n.child[len(n.child)-1] }
 
@@ -1825,3 +1900,13 @@ func arrayTypeLen(n *node) int {
 	}
 	return max + 1
 }
+
+// isValueUntyped returns true if value is untyped
+func isValueUntyped(v reflect.Value) bool {
+	// Consider only constant values.
+	if v.CanSet() {
+		return false
+	}
+	t := v.Type()
+	return t.String() == t.Kind().String()
+}

interp/doc.go

@@ -4,6 +4,18 @@ Package interp provides a complete Go interpreter.
 For the Go language itself, refer to the official Go specification
 https://golang.org/ref/spec.
 
+Importing packages
+
+Packages can be imported in source or binary form, using the standard
+Go import statement. In source form, packages are searched first in the
+vendor directory, the preferred way to store source dependencies. If not
+found in vendor, sources modules will be searched in GOPATH. Go modules
+are not supported yet by yaegi.
+
+Binary form packages are compiled and linked with the interpreter
+executable, and exposed to scripts with the Use method. The goexports
+command can be used to generate package wrappers.
+
 Custom build tags
 
 Custom build tags allow to control which files in imported source

interp/dot.go

@@ -38,7 +38,7 @@ func (n *node) astDot(out io.Writer, name string) {
 func (n *node) cfgDot(out io.Writer) {
 	fmt.Fprintf(out, "digraph cfg {\n")
 	n.Walk(nil, func(n *node) {
-		if n.kind == basicLit || n.kind == identExpr || n.tnext == nil {
+		if n.kind == basicLit || n.tnext == nil {
 			return
 		}
 		var label string

interp/gta.go

@@ -1,7 +1,6 @@
 package interp
 
 import (
-	"path"
 	"reflect"
 )
 
@@ -31,6 +30,7 @@ func (interp *Interpreter) gta(root *node, rpath string) ([]*node, error) {
 		case defineStmt:
 			var atyp *itype
 			if n.nleft+n.nright < len(n.child) {
+				// Type is declared explicitly in the assign expression.
 				if atyp, err = nodeType(interp, sc, n.child[n.nleft]); err != nil {
 					return false
 				}
@@ -126,7 +126,7 @@ func (interp *Interpreter) gta(root *node, rpath string) ([]*node, error) {
 				name = n.child[0].ident
 			} else {
 				ipath = n.child[0].rval.String()
-				name = path.Base(ipath)
+				name = identifier.FindString(ipath)
 			}
 			// Try to import a binary package first, or a source package
 			if interp.binPkg[ipath] != nil {

interp/interp_eval_test.go

@@ -47,11 +47,17 @@ func TestEvalArithmetic(t *testing.T) {
 		{desc: "shl_IN", src: "1 << -1", err: "1:28: illegal operand types for '<<' operator"},
 		{desc: "shl_IF", src: "1 << 1.0", res: "2"},
 		{desc: "shl_IF1", src: "1 << 1.1", err: "1:28: illegal operand types for '<<' operator"},
-		{desc: "shl_IF", src: "1.0 << 1", res: "2"},
+		{desc: "shl_IF2", src: "1.0 << 1", res: "2"},
 		{desc: "shr_II", src: "1 >> 8", res: "0"},
 		{desc: "shr_IN", src: "1 >> -1", err: "1:28: illegal operand types for '>>' operator"},
 		{desc: "shr_IF", src: "1 >> 1.0", res: "0"},
 		{desc: "shr_IF1", src: "1 >> 1.1", err: "1:28: illegal operand types for '>>' operator"},
+		{desc: "neg_I", src: "-2", res: "-2"},
+		{desc: "pos_I", src: "+2", res: "2"},
+		{desc: "bitnot_I", src: "^2", res: "-3"},
+		{desc: "bitnot_F", src: "^0.2", err: "1:28: illegal operand type for '^' operator"},
+		{desc: "not_B", src: "!false", res: "true"},
+		{desc: "not_I", src: "!0", err: "1:28: illegal operand type for '!' operator"},
 	})
 }
 

interp/op.go

@@ -1864,6 +1864,57 @@ func inc(n *node) {
 	}
 }
 
+func bitNotConst(n *node) {
+	t := n.typ.rtype
+	v := n.child[0].rval
+	n.rval = reflect.New(t).Elem()
+	switch t.Kind() {
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		n.rval.SetInt(^v.Int())
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
+		n.rval.SetUint(^v.Uint())
+	}
+}
+
+func negConst(n *node) {
+	t := n.typ.rtype
+	v := n.child[0].rval
+	n.rval = reflect.New(t).Elem()
+	switch t.Kind() {
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		n.rval.SetInt(-v.Int())
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
+		n.rval.SetUint(-v.Uint())
+	case reflect.Float32, reflect.Float64:
+		n.rval.SetFloat(-v.Float())
+	case reflect.Complex64, reflect.Complex128:
+		n.rval.SetComplex(-v.Complex())
+	}
+}
+
+func notConst(n *node) {
+	t := n.typ.rtype
+	v := n.child[0].rval
+	n.rval = reflect.New(t).Elem()
+	n.rval.SetBool(!v.Bool())
+}
+
+func posConst(n *node) {
+	t := n.typ.rtype
+	v := n.child[0].rval
+	n.rval = reflect.New(t).Elem()
+	switch t.Kind() {
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		n.rval.SetInt(+v.Int())
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
+		n.rval.SetUint(+v.Uint())
+	case reflect.Float32, reflect.Float64:
+		n.rval.SetFloat(+v.Float())
+	case reflect.Complex64, reflect.Complex128:
+		n.rval.SetComplex(+v.Complex())
+	}
+}
+
 func equal(n *node) {
 	tnext := getExec(n.tnext)
 	dest := genValue(n)

interp/run.go

@@ -24,6 +24,7 @@ var builtin = [...]bltnGenerator{
 	aAndAssign:    andAssign,
 	aAndNot:       andNot,
 	aAndNotAssign: andNotAssign,
+	aBitNot:       bitNot,
 	aCall:         call,
 	aCase:         _case,
 	aCompositeLit: arrayLit,
@@ -40,11 +41,12 @@ var builtin = [...]bltnGenerator{
 	aLowerEqual:   lowerEqual,
 	aMul:          mul,
 	aMulAssign:    mulAssign,
-	aNegate:       negate,
+	aNeg:          neg,
 	aNot:          not,
 	aNotEqual:     notEqual,
 	aOr:           or,
 	aOrAssign:     orAssign,
+	aPos:          pos,
 	aQuo:          quo,
 	aQuoAssign:    quoAssign,
 	aRange:        _range,
@@ -239,7 +241,7 @@ func isRecursiveStruct(t *itype, rtype reflect.Type) bool {
 	if t.cat == structT && rtype.Kind() == reflect.Interface {
 		return true
 	}
-	if t.cat == ptrT {
+	if t.cat == ptrT && t.rtype != nil {
 		return isRecursiveStruct(t.val, t.rtype.Elem())
 	}
 	return false
@@ -260,7 +262,7 @@ func assign(n *node) {
 		switch {
 		case dest.typ.cat == interfaceT:
 			svalue[i] = genValueInterface(src)
-		case dest.typ.cat == valueT && dest.typ.rtype.Kind() == reflect.Interface:
+		case (dest.typ.cat == valueT || dest.typ.cat == errorT) && dest.typ.rtype.Kind() == reflect.Interface:
 			svalue[i] = genInterfaceWrapper(src, dest.typ.rtype)
 		case dest.typ.cat == valueT && src.typ.cat == funcT:
 			svalue[i] = genFunctionWrapper(src)
@@ -340,21 +342,24 @@ func assign(n *node) {
 }
 
 func not(n *node) {
+	dest := genValue(n)
 	value := genValue(n.child[0])
 	tnext := getExec(n.tnext)
+	i := n.findex
 
 	if n.fnext != nil {
 		fnext := getExec(n.fnext)
 		n.exec = func(f *frame) bltn {
 			if !value(f).Bool() {
+				f.data[i].SetBool(true)
 				return tnext
 			}
+			f.data[i].SetBool(false)
 			return fnext
 		}
 	} else {
-		i := n.findex
 		n.exec = func(f *frame) bltn {
-			f.data[i].SetBool(!value(f).Bool())
+			dest(f).SetBool(!value(f).Bool())
 			return tnext
 		}
 	}
@@ -658,7 +663,7 @@ func call(n *node) {
 				values = append(values, func(f *frame) reflect.Value { return f.data[ind] })
 			}
 		default:
-			if c.kind == basicLit {
+			if c.kind == basicLit || c.rval.IsValid() {
 				var argType reflect.Type
 				if variadic >= 0 && i >= variadic {
 					argType = n.child[0].typ.arg[variadic].val.TypeOf()
@@ -843,7 +848,7 @@ func callBin(n *node) {
 				values = append(values, func(f *frame) reflect.Value { return f.data[ind] })
 			}
 		default:
-			if c.kind == basicLit {
+			if c.kind == basicLit || c.rval.IsValid() {
 				// Convert literal value (untyped) to function argument type (if not an interface{})
 				var argType reflect.Type
 				if variadic >= 0 && i >= variadic {
@@ -1246,7 +1251,7 @@ func getIndexSeqMethod(n *node) {
 	}
 }
 
-func negate(n *node) {
+func neg(n *node) {
 	dest := genValue(n)
 	value := genValue(n.child[0])
 	next := getExec(n.tnext)
@@ -1270,6 +1275,37 @@ func negate(n *node) {
 	}
 }
 
+func pos(n *node) {
+	dest := genValue(n)
+	value := genValue(n.child[0])
+	next := getExec(n.tnext)
+
+	n.exec = func(f *frame) bltn {
+		dest(f).Set(value(f))
+		return next
+	}
+}
+
+func bitNot(n *node) {
+	dest := genValue(n)
+	value := genValue(n.child[0])
+	next := getExec(n.tnext)
+	typ := n.typ.TypeOf()
+
+	switch typ.Kind() {
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		n.exec = func(f *frame) bltn {
+			dest(f).SetInt(^value(f).Int())
+			return next
+		}
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
+		n.exec = func(f *frame) bltn {
+			dest(f).SetUint(^value(f).Uint())
+			return next
+		}
+	}
+}
+
 func land(n *node) {
 	value0 := genValue(n.child[0])
 	value1 := genValue(n.child[1])
@@ -1946,7 +1982,7 @@ func _close(n *node) {
 }
 
 func _complex(n *node) {
-	i := n.findex
+	dest := genValue(n)
 	c1, c2 := n.child[1], n.child[2]
 	convertLiteralValue(c1, floatType)
 	convertLiteralValue(c2, floatType)
@@ -1956,38 +1992,38 @@ func _complex(n *node) {
 
 	if typ := n.typ.TypeOf(); isComplex(typ) {
 		n.exec = func(f *frame) bltn {
-			f.data[i].SetComplex(complex(value0(f).Float(), value1(f).Float()))
+			dest(f).SetComplex(complex(value0(f).Float(), value1(f).Float()))
 			return next
 		}
 	} else {
 		// Not a complex type: ignore imaginary part
 		n.exec = func(f *frame) bltn {
-			f.data[i].Set(value0(f).Convert(typ))
+			dest(f).Set(value0(f).Convert(typ))
 			return next
 		}
 	}
 }
 
 func _imag(n *node) {
-	i := n.findex
+	dest := genValue(n)
 	convertLiteralValue(n.child[1], complexType)
 	value := genValue(n.child[1])
 	next := getExec(n.tnext)
 
 	n.exec = func(f *frame) bltn {
-		f.data[i].SetFloat(imag(value(f).Complex()))
+		dest(f).SetFloat(imag(value(f).Complex()))
 		return next
 	}
 }
 
 func _real(n *node) {
-	i := n.findex
+	dest := genValue(n)
 	convertLiteralValue(n.child[1], complexType)
 	value := genValue(n.child[1])
 	next := getExec(n.tnext)
 
 	n.exec = func(f *frame) bltn {
-		f.data[i].SetFloat(real(value(f).Complex()))
+		dest(f).SetFloat(real(value(f).Complex()))
 		return next
 	}
 }
@@ -2005,12 +2041,12 @@ func _delete(n *node) {
 }
 
 func _len(n *node) {
-	i := n.findex
+	dest := genValue(n)
 	value := genValue(n.child[1])
 	next := getExec(n.tnext)
 
 	n.exec = func(f *frame) bltn {
-		f.data[i].SetInt(int64(value(f).Len()))
+		dest(f).SetInt(int64(value(f).Len()))
 		return next
 	}
 }
@@ -2222,13 +2258,16 @@ func recv2(n *node) {
 }
 
 func convertLiteralValue(n *node, t reflect.Type) {
-	if n.kind != basicLit || t == nil || t.Kind() == reflect.Interface {
+	// Skip non-constant values, undefined target type or interface target type.
+	if !(n.kind == basicLit || n.rval.IsValid()) || t == nil || t.Kind() == reflect.Interface {
 		return
 	}
 	if n.rval.IsValid() {
+		// Convert constant value to target type.
 		n.rval = n.rval.Convert(t)
 	} else {
-		n.rval = reflect.New(t).Elem() // convert to type nil value
+		// Create a zero value of target type.
+		n.rval = reflect.New(t).Elem()
 	}
 }
 
@@ -2420,19 +2459,21 @@ func isNil(n *node) {
 		value = genValue(n.child[0])
 	}
 	tnext := getExec(n.tnext)
+	dest := genValue(n)
 
 	if n.fnext != nil {
 		fnext := getExec(n.fnext)
 		n.exec = func(f *frame) bltn {
 			if value(f).IsNil() {
+				dest(f).SetBool(true)
 				return tnext
 			}
+			dest(f).SetBool(false)
 			return fnext
 		}
 	} else {
-		i := n.findex
 		n.exec = func(f *frame) bltn {
-			f.data[i].SetBool(value(f).IsNil())
+			dest(f).SetBool(value(f).IsNil())
 			return tnext
 		}
 	}
@@ -2446,19 +2487,21 @@ func isNotNil(n *node) {
 		value = genValue(n.child[0])
 	}
 	tnext := getExec(n.tnext)
+	dest := genValue(n)
 
 	if n.fnext != nil {
 		fnext := getExec(n.fnext)
 		n.exec = func(f *frame) bltn {
 			if value(f).IsNil() {
+				dest(f).SetBool(false)
 				return fnext
 			}
+			dest(f).SetBool(true)
 			return tnext
 		}
 	} else {
-		i := n.findex
 		n.exec = func(f *frame) bltn {
-			f.data[i].SetBool(!value(f).IsNil())
+			dest(f).SetBool(!value(f).IsNil())
 			return tnext
 		}
 	}

interp/type.go

@@ -401,6 +401,9 @@ func nodeType(interp *Interpreter, sc *scope, n *node) (*itype, error) {
 				t.method = m
 				sym.typ = t
 			}
+			if t.node == nil {
+				t.node = n
+			}
 		} else {
 			t.incomplete = true
 			sc.sym[n.ident] = &symbol{kind: typeSym, typ: t}
@@ -636,6 +639,74 @@ func (t *itype) finalize() (*itype, error) {
 	return t, err
 }
 
+// Equals returns true if the given type is identical to the receiver one.
+func (t *itype) equals(o *itype) bool {
+	switch ti, oi := isInterface(t), isInterface(o); {
+	case ti && oi:
+		return t.methods().equals(o.methods())
+	case ti && !oi:
+		return o.methods().contains(t.methods())
+	case oi && !ti:
+		return t.methods().contains(o.methods())
+	default:
+		return t.id() == o.id()
+	}
+}
+
+// MethodSet defines the set of methods signatures as strings, indexed per method name.
+type methodSet map[string]string
+
+// Contains returns true if the method set m contains the method set n.
+func (m methodSet) contains(n methodSet) bool {
+	for k, v := range n {
+		if m[k] != v {
+			return false
+		}
+	}
+	return true
+}
+
+// Equal returns true if the method set m is equal to the method set n.
+func (m methodSet) equals(n methodSet) bool {
+	return m.contains(n) && n.contains(m)
+}
+
+// Methods returns a map of method type strings, indexed by method names.
+func (t *itype) methods() methodSet {
+	res := make(methodSet)
+	switch t.cat {
+	case interfaceT:
+		// Get methods from recursive analysis of interface fields
+		for _, f := range t.field {
+			if f.typ.cat == funcT {
+				res[f.name] = f.typ.TypeOf().String()
+			} else {
+				for k, v := range f.typ.methods() {
+					res[k] = v
+				}
+			}
+		}
+	case valueT, errorT:
+		// Get method from corresponding reflect.Type
+		for i := t.rtype.NumMethod() - 1; i >= 0; i-- {
+			m := t.rtype.Method(i)
+			res[m.Name] = m.Type.String()
+		}
+	case ptrT:
+		// Consider only methods where receiver is a pointer to type t
+		for _, m := range t.val.method {
+			if m.child[0].child[0].lastChild().typ.cat == ptrT {
+				res[m.ident] = m.typ.TypeOf().String()
+			}
+		}
+	default:
+		for _, m := range t.method {
+			res[m.ident] = m.typ.TypeOf().String()
+		}
+	}
+	return res
+}
+
 // id returns a unique type identificator string
 func (t *itype) id() string {
 	// TODO: if res is nil, build identity from String()
@@ -814,7 +885,9 @@ func (t *itype) refType(defined map[string]bool) reflect.Type {
 			panic(err)
 		}
 	}
-	if t.val != nil && defined[t.val.name] {
+	if t.val != nil && defined[t.val.name] && !t.val.incomplete && t.val.rtype == nil {
+		// Replace reference to self (direct or indirect) by an interface{} to handle
+		// recursive types with reflect.
 		t.val.rtype = interf
 	}
 	switch t.cat {
@@ -834,15 +907,9 @@ func (t *itype) refType(defined map[string]bool) reflect.Type {
 		in := make([]reflect.Type, len(t.arg))
 		out := make([]reflect.Type, len(t.ret))
 		for i, v := range t.arg {
-			if defined[v.name] {
-				v.rtype = interf
-			}
 			in[i] = v.refType(defined)
 		}
 		for i, v := range t.ret {
-			if defined[v.name] {
-				v.rtype = interf
-			}
 			out[i] = v.refType(defined)
 		}
 		t.rtype = reflect.FuncOf(in, out, false)
@@ -933,7 +1000,11 @@ func isInterface(t *itype) bool {
 	return isInterfaceSrc(t) || t.TypeOf().Kind() == reflect.Interface
 }
 
-func isStruct(t *itype) bool { return t.TypeOf().Kind() == reflect.Struct }
+func isStruct(t *itype) bool {
+	// Test first for a struct category, because a recursive interpreter struct may be
+	// represented by an interface{} at reflect level.
+	return t.cat == structT || t.TypeOf().Kind() == reflect.Struct
+}
 
 func isBool(t *itype) bool { return t.TypeOf().Kind() == reflect.Bool }
 

stdlib/stdlib.go

@@ -1,5 +1,6 @@
 // +build go1.12,!go1.14
 
+// Package stdlib provides wrappers of standard library packages to be imported natively in Yaegi.
 package stdlib
 
 import "reflect"

stdlib/syscall/syscall.go

@@ -1,5 +1,6 @@
 // +build go1.12,!go1.14
 
+// Package syscall provide wrapper of standard library syscall package for native import in Yaegi.
 package syscall
 
 import "reflect"

stdlib/unsafe/unsafe.go

@@ -1,5 +1,6 @@
 // +build go1.12,!go1.14
 
+// Package unsafe provides wrapper of standard library unsafe package to be imported natively in Yaegi.
 package unsafe
 
 import "reflect"