moved: error if not targeting a resource address (#35850)

* moved: error if not targeting a resource address

* address comments

internal/addrs/parse_target.go

@@ -181,6 +181,15 @@ func parseResourceInstanceUnderModule(moduleAddr ModuleInstance, allowPartial bo
 		// Starting a resource address with "resource" is optional, so we'll
 		// just ignore it.
 		remain = remain[1:]
+	case "count", "each", "local", "module", "path", "self", "terraform", "var", "template", "lazy", "arg":
+		// These are all reserved words that are not valid as resource types.
+		diags = diags.Append(&hcl.Diagnostic{
+			Severity: hcl.DiagError,
+			Summary:  "Invalid address",
+			Detail:   fmt.Sprintf("The keyword %q is reserved and cannot be used to target a resource address. If you are targeting a resource type that uses a reserved keyword, please prefix your address with \"resource.\".", remain.RootName()),
+			Subject:  remain.SourceRange().Ptr(),
+		})
+		return AbsResourceInstance{}, diags
 	}
 
 	if len(remain) < 2 {

internal/addrs/parse_target_test.go

@@ -431,6 +431,61 @@ func TestParseTarget(t *testing.T) {
 			nil,
 			`Unexpected extra operators after address.`,
 		},
+		{
+			`each.key`,
+			nil,
+			`The keyword "each" is reserved and cannot be used to target a resource address. If you are targeting a resource type that uses a reserved keyword, please prefix your address with "resource.".`,
+		},
+		{
+			`module.foo[1].each`,
+			nil,
+			`The keyword "each" is reserved and cannot be used to target a resource address. If you are targeting a resource type that uses a reserved keyword, please prefix your address with "resource.".`,
+		},
+		{
+			`count.index`,
+			nil,
+			`The keyword "count" is reserved and cannot be used to target a resource address. If you are targeting a resource type that uses a reserved keyword, please prefix your address with "resource.".`,
+		},
+		{
+			`local.value`,
+			nil,
+			`The keyword "local" is reserved and cannot be used to target a resource address. If you are targeting a resource type that uses a reserved keyword, please prefix your address with "resource.".`,
+		},
+		{
+			`path.root`,
+			nil,
+			`The keyword "path" is reserved and cannot be used to target a resource address. If you are targeting a resource type that uses a reserved keyword, please prefix your address with "resource.".`,
+		},
+		{
+			`self.id`,
+			nil,
+			`The keyword "self" is reserved and cannot be used to target a resource address. If you are targeting a resource type that uses a reserved keyword, please prefix your address with "resource.".`,
+		},
+		{
+			`terraform.planning`,
+			nil,
+			`The keyword "terraform" is reserved and cannot be used to target a resource address. If you are targeting a resource type that uses a reserved keyword, please prefix your address with "resource.".`,
+		},
+		{
+			`var.foo`,
+			nil,
+			`The keyword "var" is reserved and cannot be used to target a resource address. If you are targeting a resource type that uses a reserved keyword, please prefix your address with "resource.".`,
+		},
+		{
+			`template`,
+			nil,
+			`The keyword "template" is reserved and cannot be used to target a resource address. If you are targeting a resource type that uses a reserved keyword, please prefix your address with "resource.".`,
+		},
+		{
+			`lazy`,
+			nil,
+			`The keyword "lazy" is reserved and cannot be used to target a resource address. If you are targeting a resource type that uses a reserved keyword, please prefix your address with "resource.".`,
+		},
+		{
+			`arg`,
+			nil,
+			`The keyword "arg" is reserved and cannot be used to target a resource address. If you are targeting a resource type that uses a reserved keyword, please prefix your address with "resource.".`,
+		},
 	}
 
 	for _, test := range tests {

website/docs/language/moved.mdx

@@ -16,8 +16,8 @@ The `moved` block programmatically changes the address of a resource. Refer to [
 The following list outlines field hierarchy, language-specific data types, and requirements in the `moved` block. 
 
 - [`moved`](#moved): map
-  - [`from`](#moved): string
-  - [`to`](#moved): string
+  - [`from`](#moved): reference
+  - [`to`](#moved): reference
 
 ## Complete configuration