proc/variables: bugfix: disable cast to maps and channels

It's was implemented unintentionally and the unintentional
implementation doesn't work and causes a crash.

proc/eval.go

@@ -139,6 +139,9 @@ func (scope *EvalScope) evalTypeCast(node *ast.CallExpr) (*Variable, error) {
 
 	switch ttyp := typ.(type) {
 	case *dwarf.PtrType:
+		if ptrTypeKind(ttyp) != reflect.Ptr {
+			return nil, converr
+		}
 		switch argv.Kind {
 		case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
 			// ok

proc/variables.go

@@ -119,6 +119,20 @@ func (err *IsNilErr) Error() string {
 	return fmt.Sprintf("%s is nil", err.name)
 }
 
+func ptrTypeKind(t *dwarf.PtrType) reflect.Kind {
+	structtyp, isstruct := t.Type.(*dwarf.StructType)
+	_, isvoid := t.Type.(*dwarf.VoidType)
+	if isstruct && strings.HasPrefix(structtyp.StructName, "hchan<") {
+		return reflect.Chan
+	} else if isstruct && strings.HasPrefix(structtyp.StructName, "hash<") {
+		return reflect.Map
+	} else if isvoid {
+		return reflect.UnsafePointer
+	} else {
+		return reflect.Ptr
+	}
+}
+
 func newVariable(name string, addr uintptr, dwarfType dwarf.Type, thread *Thread) *Variable {
 	v := &Variable{
 		Name:      name,
@@ -131,17 +145,7 @@ func newVariable(name string, addr uintptr, dwarfType dwarf.Type, thread *Thread
 
 	switch t := v.RealType.(type) {
 	case *dwarf.PtrType:
-		structtyp, isstruct := t.Type.(*dwarf.StructType)
-		_, isvoid := t.Type.(*dwarf.VoidType)
-		if isstruct && strings.HasPrefix(structtyp.StructName, "hchan<") {
-			v.Kind = reflect.Chan
-		} else if isstruct && strings.HasPrefix(structtyp.StructName, "hash<") {
-			v.Kind = reflect.Map
-		} else if isvoid {
-			v.Kind = reflect.UnsafePointer
-		} else {
-			v.Kind = reflect.Ptr
-		}
+		v.Kind = ptrTypeKind(t)
 	case *dwarf.StructType:
 		switch {
 		case t.StructName == "string":

service/test/variables_test.go

@@ -533,6 +533,7 @@ func TestEvalExpression(t *testing.T) {
 		{"nil[0]", false, "", "", "", fmt.Errorf("expression \"nil\" (nil) does not support indexing")},
 		{"nil[2:10]", false, "", "", "", fmt.Errorf("can not slice \"nil\" (type nil)")},
 		{"nil.member", false, "", "", "", fmt.Errorf("type nil is not a struct")},
+		{"(map[string]int)(0x4000)", false, "", "", "", fmt.Errorf("can not convert \"0x4000\" to *struct hash<string,int>")},
 
 		// typecasts
 		{"uint(i2)", false, "2", "", "uint", nil},