Rewrite AST prior go type checking to avoid inter-realm statements.

Author: mvertes

gnovm/pkg/gnolang/gotypecheck.go

@@ -13,6 +13,7 @@ import (
 
 	"github.com/gnolang/gno/gnovm"
 	"go.uber.org/multierr"
+	"golang.org/x/tools/go/ast/astutil"
 )
 
 // type checking (using go/types)
@@ -140,6 +141,8 @@ func (g *gnoImporter) parseCheckMemPackage(mpkg *gnovm.MemPackage, fmt bool) (*t
 			deleteOldIdents(delFunc, f)
 		}
 
+		filterWithSwitchRealm(f)
+
 		// enforce formatting
 		if fmt {
 			var buf bytes.Buffer
@@ -179,3 +182,27 @@ func deleteOldIdents(idents map[string]func(), f *ast.File) {
 		}
 	}
 }
+
+func filterWithSwitchRealm(f *ast.File) {
+	astutil.Apply(f, nil, func(c *astutil.Cursor) bool {
+		switch n := c.Node().(type) {
+		case *ast.ExprStmt:
+			if ce, ok := n.X.(*ast.CallExpr); ok {
+				if id, ok := ce.Fun.(*ast.Ident); ok && id.Name == "switchrealm" {
+					// Delete statement 'switchrealm()'.
+					c.Delete()
+				}
+			}
+		case *ast.CallExpr:
+			if id, ok := n.Fun.(*ast.Ident); ok && id.Name == "withswitch" {
+				// Replace expression 'withswitch(x)' by 'x'.
+				var a ast.Node
+				if len(n.Args) > 0 {
+					a = n.Args[0]
+				}
+				c.Replace(a)
+			}
+		}
+		return true
+	})
+}

gnovm/pkg/test/filetest.go

@@ -262,6 +262,12 @@ func (opts *TestOptions) runTest(m *gno.Machine, pkgPath, filename string, conte
 		}
 		orig, tx := m.Store, m.Store.BeginTransaction(nil, nil, nil)
 		m.Store = tx
+
+		// Validate Gno syntax and type check.
+		if err := gno.TypeCheckMemPackageTest(memPkg, m.Store); err != nil {
+			return runResult{Error: err.Error()}
+		}
+
 		// Run decls and init functions.
 		m.RunMemPackage(memPkg, true)
 		// Clear store cache and reconstruct machine from committed info

gnovm/tests/files/extern/timtadh/data_structures/types/string.gno

@@ -70,8 +70,8 @@ func (self ByteSlice) Hash() int {
 
 func hash(s []byte) int {
 	res := sha256.Sum256(s)
-	return int(s[0]) |
-		int(s[1]<<8) |
-		int(s[2]<<16) |
-		int(s[3]<<24)
+	return int(res[0]) |
+		int(res[1]<<8) |
+		int(res[2]<<16) |
+		int(res[3]<<24)
 }