compiler: enforce Hash160 and Hash256 size in literals

Can be useful to prevent small typos.

pkg/compiler/codegen.go

@@ -14,6 +14,7 @@ import (
 
 	"github.com/nspcc-dev/neo-go/pkg/encoding/address"
 	"github.com/nspcc-dev/neo-go/pkg/io"
+	"github.com/nspcc-dev/neo-go/pkg/smartcontract"
 	"github.com/nspcc-dev/neo-go/pkg/vm"
 	"github.com/nspcc-dev/neo-go/pkg/vm/emit"
 	"github.com/nspcc-dev/neo-go/pkg/vm/opcode"
@@ -746,12 +747,27 @@ func (c *codegen) Visit(node ast.Node) ast.Visitor {
 		return nil
 
 	case *ast.CompositeLit:
-		switch typ := c.typeOf(n).Underlying().(type) {
+		t := c.typeOf(n)
+		switch typ := t.Underlying().(type) {
 		case *types.Struct:
 			c.convertStruct(n, false)
 		case *types.Map:
 			c.convertMap(n)
 		default:
+			if tn, ok := t.(*types.Named); ok && isInteropPath(tn.String()) {
+				st, _ := scAndVMInteropTypeFromExpr(tn)
+				expectedLen := -1
+				switch st {
+				case smartcontract.Hash160Type:
+					expectedLen = 20
+				case smartcontract.Hash256Type:
+					expectedLen = 32
+				}
+				if expectedLen != -1 && expectedLen != len(n.Elts) {
+					c.prog.Err = fmt.Errorf("%s type must have size %d", tn.Obj().Name(), expectedLen)
+					return nil
+				}
+			}
 			ln := len(n.Elts)
 			// ByteArrays needs a different approach than normal arrays.
 			if isByteSlice(typ) {

pkg/compiler/debug.go

@@ -228,13 +228,7 @@ func (c *codegen) scAndVMReturnTypeFromScope(scope *funcScope) (smartcontract.Pa
 	}
 }
 
-func (c *codegen) scAndVMTypeFromExpr(typ ast.Expr) (smartcontract.ParamType, stackitem.Type) {
+func scAndVMInteropTypeFromExpr(named *types.Named) (smartcontract.ParamType, stackitem.Type) {
-	t := c.typeOf(typ)
-	if c.typeOf(typ) == nil {
-		return smartcontract.AnyType, stackitem.AnyT
-	}
-	if named, ok := t.(*types.Named); ok {
-		if isInteropPath(named.String()) {
 	name := named.Obj().Name()
 	pkg := named.Obj().Pkg().Name()
 	switch pkg {
@@ -255,6 +249,16 @@ func (c *codegen) scAndVMTypeFromExpr(typ ast.Expr) (smartcontract.ParamType, st
 		}
 	}
 	return smartcontract.InteropInterfaceType, stackitem.InteropT
+}
+
+func (c *codegen) scAndVMTypeFromExpr(typ ast.Expr) (smartcontract.ParamType, stackitem.Type) {
+	t := c.typeOf(typ)
+	if c.typeOf(typ) == nil {
+		return smartcontract.AnyType, stackitem.AnyT
+	}
+	if named, ok := t.(*types.Named); ok {
+		if isInteropPath(named.String()) {
+			return scAndVMInteropTypeFromExpr(named)
 		}
 	}
 	switch t := t.Underlying().(type) {

pkg/compiler/interop_test.go

@@ -15,6 +15,7 @@ import (
 	"github.com/nspcc-dev/neo-go/pkg/core/storage"
 	"github.com/nspcc-dev/neo-go/pkg/crypto/hash"
 	"github.com/nspcc-dev/neo-go/pkg/encoding/address"
+	cinterop "github.com/nspcc-dev/neo-go/pkg/interop"
 	"github.com/nspcc-dev/neo-go/pkg/smartcontract"
 	"github.com/nspcc-dev/neo-go/pkg/smartcontract/trigger"
 	"github.com/nspcc-dev/neo-go/pkg/vm"
@@ -23,6 +24,42 @@ import (
 	"go.uber.org/zap/zaptest"
 )
 
+func TestTypeConstantSize(t *testing.T) {
+	src := `package foo
+	import "github.com/nspcc-dev/neo-go/pkg/interop"
+	var a %T // type declaration is always ok
+	func Main() interface{} {
+		return %#v
+	}`
+
+	t.Run("Hash160", func(t *testing.T) {
+		t.Run("good", func(t *testing.T) {
+			a := make(cinterop.Hash160, 20)
+			src := fmt.Sprintf(src, a, a)
+			eval(t, src, []byte(a))
+		})
+		t.Run("bad", func(t *testing.T) {
+			a := make(cinterop.Hash160, 19)
+			src := fmt.Sprintf(src, a, a)
+			_, err := compiler.Compile("foo.go", strings.NewReader(src))
+			require.Error(t, err)
+		})
+	})
+	t.Run("Hash256", func(t *testing.T) {
+		t.Run("good", func(t *testing.T) {
+			a := make(cinterop.Hash256, 32)
+			src := fmt.Sprintf(src, a, a)
+			eval(t, src, []byte(a))
+		})
+		t.Run("bad", func(t *testing.T) {
+			a := make(cinterop.Hash256, 31)
+			src := fmt.Sprintf(src, a, a)
+			_, err := compiler.Compile("foo.go", strings.NewReader(src))
+			require.Error(t, err)
+		})
+	})
+}
+
 func TestFromAddress(t *testing.T) {
 	as1 := "NQRLhCpAru9BjGsMwk67vdMwmzKMRgsnnN"
 	addr1, err := address.StringToUint160(as1)