fix: allow keywords as block type names and labels

CHANGELOG.md

@@ -7,7 +7,9 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 
 ## \[Unreleased\]
 
-- Nothing yet.
+### Fixed
+
+- Parse keywords as block types and block labels, not only as attribute names. `in { ... }`, `for { ... }`, `for_each { ... }`, and `resource in { ... }` all failed to parse even though the matching attribute form `in = 1` worked. Keywords are reserved only inside expressions; in a body they are ordinary names. ([#355](https://github.com/amplify-education/python-hcl2/pull/355))
 
 ## \[8.1.3\] - 2026-08-26
 

hcl2/hcl2.lark

@@ -113,7 +113,7 @@ start : body
 body : (new_line_or_comment? (attribute | block))* new_line_or_comment?
 attribute : _attribute_name EQ expression
 _attribute_name : identifier | keyword | literal_value
-block : identifier (identifier | string)* new_line_or_comment? LBRACE body RBRACE
+block : _attribute_name (_attribute_name | string)* new_line_or_comment? LBRACE body RBRACE
 
 // Whitespace and comments
 new_line_or_comment: ( NL_OR_COMMENT )+

hcl2/transformer.py

@@ -130,6 +130,14 @@ def body(self, meta: Meta, args) -> BodyRule:
 
     @v_args(meta=True)
     def block(self, meta: Meta, args) -> BlockRule:
+        # _attribute_name is flattened, so the block type and bare labels may be
+        # KeywordRule or LiteralValueRule; normalize so labels are all one type.
+        args = [
+            IdentifierRule([NAME(a.token.value)], meta)
+            if isinstance(a, (KeywordRule, LiteralValueRule))
+            else a
+            for a in args
+        ]
         return BlockRule(args, meta)
 
     @v_args(meta=True)

test/integration/hcl2_original/resource_keyword_block.tf

@@ -0,0 +1,31 @@
+resource "custom_provider_resource" "resource_name" {
+  name = "resource_name"
+
+  if {
+    value = "block_value1"
+  }
+
+  in {
+    value = "block_value2"
+  }
+
+  for {
+    value = "block_value3"
+  }
+
+  for_each {
+    value = "block_value4"
+  }
+
+  true {
+    value = "block_value5"
+  }
+}
+
+in "labeled_block" {
+  value = "top_level_value"
+}
+
+resource in {
+  value = "keyword_label_value"
+}

test/integration/hcl2_reconstructed/resource_keyword_block.tf

@@ -0,0 +1,37 @@
+resource "custom_provider_resource" "resource_name" {
+  name = "resource_name"
+
+  if {
+    value = "block_value1"
+  }
+
+
+  in {
+    value = "block_value2"
+  }
+
+
+  for {
+    value = "block_value3"
+  }
+
+
+  for_each {
+    value = "block_value4"
+  }
+
+
+  true {
+    value = "block_value5"
+  }
+}
+
+
+resource in {
+  value = "keyword_label_value"
+}
+
+
+in "labeled_block" {
+  value = "top_level_value"
+}

test/integration/json_reserialized/resource_keyword_block.json

@@ -0,0 +1,56 @@
+{
+  "resource": [
+    {
+      "\"custom_provider_resource\"": {
+        "\"resource_name\"": {
+          "name": "\"resource_name\"",
+          "if": [
+            {
+              "value": "\"block_value1\"",
+              "__is_block__": true
+            }
+          ],
+          "in": [
+            {
+              "value": "\"block_value2\"",
+              "__is_block__": true
+            }
+          ],
+          "for": [
+            {
+              "value": "\"block_value3\"",
+              "__is_block__": true
+            }
+          ],
+          "for_each": [
+            {
+              "value": "\"block_value4\"",
+              "__is_block__": true
+            }
+          ],
+          "true": [
+            {
+              "value": "\"block_value5\"",
+              "__is_block__": true
+            }
+          ],
+          "__is_block__": true
+        }
+      }
+    },
+    {
+      "in": {
+        "value": "\"keyword_label_value\"",
+        "__is_block__": true
+      }
+    }
+  ],
+  "in": [
+    {
+      "\"labeled_block\"": {
+        "value": "\"top_level_value\"",
+        "__is_block__": true
+      }
+    }
+  ]
+}

test/integration/json_serialized/resource_keyword_block.json

@@ -0,0 +1,56 @@
+{
+  "resource": [
+    {
+      "\"custom_provider_resource\"": {
+        "\"resource_name\"": {
+          "name": "\"resource_name\"",
+          "if": [
+            {
+              "value": "\"block_value1\"",
+              "__is_block__": true
+            }
+          ],
+          "in": [
+            {
+              "value": "\"block_value2\"",
+              "__is_block__": true
+            }
+          ],
+          "for": [
+            {
+              "value": "\"block_value3\"",
+              "__is_block__": true
+            }
+          ],
+          "for_each": [
+            {
+              "value": "\"block_value4\"",
+              "__is_block__": true
+            }
+          ],
+          "true": [
+            {
+              "value": "\"block_value5\"",
+              "__is_block__": true
+            }
+          ],
+          "__is_block__": true
+        }
+      }
+    },
+    {
+      "in": {
+        "value": "\"keyword_label_value\"",
+        "__is_block__": true
+      }
+    }
+  ],
+  "in": [
+    {
+      "\"labeled_block\"": {
+        "value": "\"top_level_value\"",
+        "__is_block__": true
+      }
+    }
+  ]
+}