toml: fix implicit allocation overwrite of existing table (#12793)

vlib/toml/tests/value_query_test.v

@@ -1,7 +1,8 @@
 import toml
 import strconv
 
-const toml_text = '
+const (
+	toml_text = '
 modules = [ "ui", "toml" ]
 errors = []
 
@@ -37,6 +38,17 @@ colors = [
 ]
 '
 
+	toml_text_2 = "
+[defaults]
+  run.flags = ['-f 1']
+
+  [[defaults.env]]
+    'RUN_PATH' = '\$OUT_PATH'
+    'RUN_TIME' = 5
+    'TEST_PATH' = '/tmp/test'
+"
+)
+
 fn test_value_query_in_array() {
 	toml_doc := toml.parse(toml_text) or { panic(err) }
 	mut value := toml_doc.value('themes[0].colors[1]').string()
@@ -92,3 +104,10 @@ fn test_inf_and_nan_query() {
 	value_u64 = toml_doc.value('values.minus-inf').u64()
 	assert value_u64 == strconv.double_minus_infinity
 }
+
+fn test_any_value_query_2() {
+	toml_doc := toml.parse(toml_text_2) or { panic(err) }
+	defaults := toml_doc.value('defaults')
+	assert defaults.value('run.flags[0]').string() == '-f 1'
+	assert defaults.value('env[0].RUN_TIME').int() == 5
+}