nested null

d2compiler/compile_test.go

@@ -3572,6 +3572,42 @@ hi: {
 					assert.Equal(t, "a-b", g.Objects[1].Label.Value)
 				},
 			},
+			{
+				name: "null",
+				run: func(t *testing.T) {
+					assertCompile(t, `
+vars: {
+	surname: Smith
+}
+a: {
+  vars: {
+		surname: null
+  }
+  hi: John ${surname}
+}
+`, `d2/testdata/d2compiler/TestCompile2/vars/override/null.d2:9:3: could not resolve variable "surname"`)
+				},
+			},
+			{
+				name: "nested-null",
+				run: func(t *testing.T) {
+					assertCompile(t, `
+vars: {
+	surnames: {
+    john: smith
+  }
+}
+a: {
+  vars: {
+		surnames: {
+      john: null
+    }
+  }
+  hi: John ${surname}
+}
+`, `d2/testdata/d2compiler/TestCompile2/vars/override/nested-null.d2:13:3: could not resolve variable "surname"`)
+				},
+			},
 		}
 
 		for _, tc := range tca {
@@ -3711,22 +3747,6 @@ scenarios: {
 					assert.Equal(t, "im replaced x var", g.Scenarios[0].Objects[0].Label.Value)
 				},
 			},
-			{
-				name: "null",
-				run: func(t *testing.T) {
-					assertCompile(t, `
-vars: {
-	surname: Smith
-}
-a: {
-  vars: {
-		surname: null
-  }
-  hi: John ${surname}
-}
-`, `d2/testdata/d2compiler/TestCompile2/vars/boards/null.d2:9:3: could not resolve variable "surname"`)
-				},
-			},
 		}
 
 		for _, tc := range tca {

d2ir/compile.go

@@ -331,7 +331,7 @@ func (c *compiler) compileField(dst *Map, kp *d2ast.KeyPath, refctx *RefContext)
 	if refctx.Key != nil && len(refctx.Key.Edges) == 0 && refctx.Key.Value.Null != nil {
 		// For vars, if we delete the field, it may just resolve to an outer scope var of the same name
 		// Instead we keep it around, so that resolveSubstitutions can find it
-		if ParentField(dst) == nil || ParentField(dst).Name != "vars" {
+		if !IsVar(dst) {
 			dst.DeleteField(kp.IDA()...)
 			return
 		}

d2ir/d2ir.go

@@ -1026,6 +1026,21 @@ func ParentField(n Node) *Field {
 	}
 }
 
+func IsVar(n Node) bool {
+	for {
+		if n == nil {
+			return false
+		}
+		if NodeBoardKind(n) != "" {
+			return false
+		}
+		if f, ok := n.(*Field); ok && f.Name == "vars" {
+			return true
+		}
+		n = n.Parent()
+	}
+}
+
 func ParentBoard(n Node) Node {
 	for {
 		n = n.Parent()

testdata/d2compiler/TestCompile2/vars/override/nested-null.exp.json

@@ -0,0 +1,11 @@
+{
+  "graph": null,
+  "err": {
+    "errs": [
+      {
+        "range": "d2/testdata/d2compiler/TestCompile2/vars/override/nested-null.d2,12:2:102-12:4:104",
+        "errmsg": "d2/testdata/d2compiler/TestCompile2/vars/override/nested-null.d2:13:3: could not resolve variable \"surname\""
+      }
+    ]
+  }
+}

testdata/d2compiler/TestCompile2/vars/override/null.exp.json

@@ -0,0 +1,11 @@
+{
+  "graph": null,
+  "err": {
+    "errs": [
+      {
+        "range": "d2/testdata/d2compiler/TestCompile2/vars/override/null.d2,8:2:64-8:4:66",
+        "errmsg": "d2/testdata/d2compiler/TestCompile2/vars/override/null.d2:9:3: could not resolve variable \"surname\""
+      }
+    ]
+  }
+}