address Tess' feedback

Author: SteveL-MSFT

dsc/tests/dsc_expressions.tests.ps1

@@ -5,6 +5,11 @@ Describe 'Expressions tests' {
     It 'Accessors work: <text>' -TestCases @(
         @{ text = "[parameters('test').hello]"; expected = '@{world=there}' }
         @{ text = "[parameters('test').hello.world]"; expected = 'there' }
+        @{ text = "[parameters('test').array[0]]"; expected = 'one' }
+        @{ text = "[parameters('test').array[1][1]]"; expected = 'three' }
+        @{ text = "[parameters('test').objectArray[0].name]"; expected = 'one' }
+        @{ text = "[parameters('test').objectArray[1].value[0]]"; expected = '2' }
+        @{ text = "[parameters('test').objectArray[1].value[1].name]"; expected = 'three' }
     ) {
         param($text, $expected)
         $yaml = @"

dsc_lib/src/parser/expressions.rs

@@ -120,20 +120,16 @@ impl Expression {
             for accessor in &self.accessors {
                 match accessor {
                     Accessor::Member(member) => {
-                        if !value.is_object() {
-                            return Err(DscError::Parser("Member access on non-object value".to_string()));
-                        }
                         if let Some(object) = value.as_object() {
                             if !object.contains_key(member) {
                                 return Err(DscError::Parser(format!("Member '{member}' not found")));
                             }
                             value = object[member].clone();
+                        } else {
+                            return Err(DscError::Parser("Member access on non-object value".to_string()));
                         }
                     },
                     Accessor::Index(index) => {
-                        if !value.is_array() {
-                            return Err(DscError::Parser("Index access on non-array value".to_string()));
-                        }
                         if let Some(array) = value.as_array() {
                             if !index.is_number() {
                                 return Err(DscError::Parser("Index is not a number".to_string()));
@@ -146,6 +142,8 @@ impl Expression {
                                 return Err(DscError::Parser("Index out of bounds".to_string()));
                             }
                             value = array[index].clone();
+                        } else {
+                            return Err(DscError::Parser("Index access on non-array value".to_string()));
                         }
                     },
                 }