codegen: make generated code use 'must' instead of 'flowutils'

pkg/codegen/modelgenerate/ast_helpers.go

@@ -27,10 +27,18 @@ const (
 // we don't have to do that.
 var TrailingComments = map[ast.Node]string{}
 
-// mustCall wraps a call expression in Must(...), producing AST for Must(inner).
+// mustCall wraps a call expression in must.Get(...), producing AST for must.Get(inner).
 func mustCall(inner ast.Expr) *ast.CallExpr {
 	return &ast.CallExpr{
-		Fun:  ast.NewIdent("Must"),
+		Fun:  &ast.SelectorExpr{X: ast.NewIdent("must"), Sel: ast.NewIdent("Get")},
+		Args: []ast.Expr{inner},
+	}
+}
+
+// doCall wraps a call expression in must.Do(...), producing AST for must.Do(inner).
+func doCall(inner ast.Expr) *ast.CallExpr {
+	return &ast.CallExpr{
+		Fun:  &ast.SelectorExpr{X: ast.NewIdent("must"), Sel: ast.NewIdent("Do")},
 		Args: []ast.Expr{inner},
 	}
 }