Arbitrary vars in rule refs

ast/check.go

@@ -265,6 +265,8 @@ func (tc *typeChecker) checkRule(env *TypeEnv, as *AnnotationSet, rule *Rule) {
 	}
 }
 
+// nestedObject creates a nested structure of object types, where each term on path corresponds to a level in the
+// nesting. Each term in the path only contributes to the dynamic portion of its corresponding object.
 func nestedObject(env *TypeEnv, path Ref, tpe types.Type) (types.Type, error) {
 	if len(path) == 0 {
 		return tpe, nil
@@ -279,23 +281,14 @@ func nestedObject(env *TypeEnv, path Ref, tpe types.Type) (types.Type, error) {
 		return nil, nil
 	}
 
-	var staticProperties []*types.StaticProperty
 	var dynamicProperty *types.DynamicProperty
-	if k.IsGround() {
-		key, err := JSON(path[0].Value)
-		if err != nil {
-			return nil, err
-		}
-		staticProperties = append(staticProperties, types.NewStaticProperty(key, typeV))
-	} else {
-		typeK := env.Get(k)
-		if typeK == nil {
-			return nil, nil
-		}
-		dynamicProperty = types.NewDynamicProperty(typeK, typeV)
+	typeK := env.Get(k)
+	if typeK == nil {
+		return nil, nil
 	}
+	dynamicProperty = types.NewDynamicProperty(typeK, typeV)
 
-	return types.NewObject(staticProperties, dynamicProperty), nil
+	return types.NewObject(nil, dynamicProperty), nil
 }
 
 func (tc *typeChecker) checkExpr(env *TypeEnv, expr *Expr) *Error {

ast/check_test.go

@@ -595,13 +595,9 @@ func TestCheckInferenceRules(t *testing.T) {
 			expected: types.NewObject(
 				[]*types.StaticProperty{},
 				types.NewDynamicProperty(types.S,
-					types.NewObject(
-						[]*types.StaticProperty{types.NewStaticProperty("s",
-							types.NewObject(
-								[]*types.StaticProperty{},
-								types.NewDynamicProperty(types.N, types.N),
-							))},
-						nil,
+					types.NewObject(nil,
+						types.NewDynamicProperty(types.S, types.NewObject(nil,
+							types.NewDynamicProperty(types.N, types.N))),
 					),
 				),
 			),
@@ -610,21 +606,15 @@ func TestCheckInferenceRules(t *testing.T) {
 			note:  "general ref-rules, key overrides, complete obj access",
 			rules: ruleset3,
 			ref:   "data.overrides.p.q",
-			expected: types.NewObject(
-				[]*types.StaticProperty{types.NewStaticProperty("r",
-					types.NewObject(
-						nil,
-						types.NewDynamicProperty(types.N, types.N),
-					))},
-				types.NewDynamicProperty(types.Or(types.B, types.S),
-					types.Or(
-						types.S,
-						types.NewObject(
-							[]*types.StaticProperty{types.NewStaticProperty("s", types.B)},
-							nil,
-						),
-					),
-				),
+			expected: types.NewObject(nil, types.NewDynamicProperty(
+				types.Or(types.B, types.S),
+				types.Any{
+					types.S,
+					types.NewObject(nil, types.NewDynamicProperty(
+						types.Any{types.N, types.S},
+						types.Any{types.B, types.N})),
+				},
+			),
 			),
 		},
 		{
@@ -635,11 +625,8 @@ func TestCheckInferenceRules(t *testing.T) {
 				[]*types.StaticProperty{},
 				types.NewDynamicProperty(types.S,
 					types.NewObject(
-						[]*types.StaticProperty{
-							types.NewStaticProperty("a", types.S),
-							types.NewStaticProperty("b", types.N),
-							types.NewStaticProperty("c", types.B)},
 						nil,
+						types.NewDynamicProperty(types.S, types.Any{types.B, types.N, types.S}),
 					),
 				),
 			),
@@ -648,31 +635,27 @@ func TestCheckInferenceRules(t *testing.T) {
 			note:  "general ref-rules, multiple static key overrides, intermediate obj access",
 			rules: ruleset3,
 			ref:   "data.overrides_static.p.q.foo",
-			expected: types.NewObject(
-				[]*types.StaticProperty{
-					types.NewStaticProperty("a", types.S),
-					types.NewStaticProperty("b", types.N),
-					types.NewStaticProperty("c", types.B)},
-				nil,
+			expected: types.NewObject(nil,
+				types.NewDynamicProperty(types.S, types.Any{types.B, types.N, types.S}),
 			),
 		},
 		{
 			note:     "general ref-rules, multiple static key overrides, leaf access (a)",
 			rules:    ruleset3,
 			ref:      "data.overrides_static.p.q.foo.a",
-			expected: types.S,
+			expected: types.Any{types.B, types.N, types.S}, // Dynamically build object types don't have static properties, so even though we "know" the 'a' key has a string value, we've lost this information.
 		},
 		{
 			note:     "general ref-rules, multiple static key overrides, leaf access (b)",
 			rules:    ruleset3,
 			ref:      "data.overrides_static.p.q.bar.b",
-			expected: types.N,
+			expected: types.Any{types.B, types.N, types.S},
 		},
 		{
 			note:     "general ref-rules, multiple static key overrides, leaf access (c)",
 			rules:    ruleset3,
 			ref:      "data.overrides_static.p.q.baz.c",
-			expected: types.B,
+			expected: types.Any{types.B, types.N, types.S},
 		},
 	}
 
@@ -704,6 +687,7 @@ func TestCheckInferenceRules(t *testing.T) {
 				t.Fatalf("Unexpected error %v:", err)
 			}
 
+			fmt.Println(env.tree.String())
 			result := env.Get(ref)
 			if tc.expected == nil {
 				if result != nil {

ast/env.go

@@ -357,7 +357,8 @@ func (n *typeTreeNode) Insert(path Ref, tpe types.Type, env *TypeEnv) {
 }
 
 // mergeTypes merges the types of 'a' and 'b'. If both are sets, their 'of' types are joined with an types.Or.
-// If both are objects, the key and value types of their dynamic properties are joined with types.Or:s.
+// If both are objects, the key types of their dynamic properties are joined with types.Or:s, and their value types
+// are recursively merged (using mergeTypes).
 // If 'a' and 'b' are both objects, and at least one of them have static properties, they are joined
 // with an types.Or, instead of being merged.
 // If 'a' is an Any containing an Object, and 'b' is an Object (or vice versa); AND both objects have no
@@ -381,9 +382,10 @@ func mergeTypes(a, b types.Type) types.Type {
 
 			aDynProps := a.DynamicProperties()
 			bDynProps := bObj.DynamicProperties()
-			return types.NewObject(nil, types.NewDynamicProperty(
+			dynProps := types.NewDynamicProperty(
 				types.Or(aDynProps.Key, bDynProps.Key),
-				types.Or(aDynProps.Value, bDynProps.Value)))
+				mergeTypes(aDynProps.Value, bDynProps.Value))
+			return types.NewObject(nil, dynProps)
 		} else if bAny, ok := b.(types.Any); ok && len(a.StaticProperties()) == 0 {
 			// If a is an object type with no static components ...
 			for _, t := range bAny {