From 9f9d24d6164d7256e22d99873a06cbb96ee9fad5 Mon Sep 17 00:00:00 2001
From: Vincenzo Palazzo <vincenzopalazzodev@gmail.com>
Date: Sat, 16 Apr 2022 18:29:10 +0200
Subject: [PATCH] checker: ensure that the variant SubType exists (#14053)

Signed-off-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com>
---
 vlib/v/checker/checker.v                      |  6 ++++
 .../tests/undefined_type_on_sumtype.out       | 13 +++++++
 .../tests/undefined_type_on_sumtype.vv        | 34 +++++++++++++++++++
 .../check_combination_of_alias_and_sumtype.vv |  2 ++
 4 files changed, 55 insertions(+)
 create mode 100644 vlib/v/checker/tests/undefined_type_on_sumtype.out
 create mode 100644 vlib/v/checker/tests/undefined_type_on_sumtype.vv

diff --git a/vlib/v/checker/checker.v b/vlib/v/checker/checker.v
index f817de85d0..8d3fcc3e50 100644
--- a/vlib/v/checker/checker.v
+++ b/vlib/v/checker/checker.v
@@ -4197,6 +4197,12 @@ fn (mut c Checker) ensure_type_exists(typ ast.Type, pos token.Pos) ? {
 			c.ensure_type_exists(info.key_type, pos) ?
 			c.ensure_type_exists(info.value_type, pos) ?
 		}
+		.sum_type {
+			info := sym.info as ast.SumType
+			for concrete_typ in info.concrete_types {
+				c.ensure_type_exists(concrete_typ, pos) ?
+			}
+		}
 		else {}
 	}
 }
diff --git a/vlib/v/checker/tests/undefined_type_on_sumtype.out b/vlib/v/checker/tests/undefined_type_on_sumtype.out
new file mode 100644
index 0000000000..e664d3004a
--- /dev/null
+++ b/vlib/v/checker/tests/undefined_type_on_sumtype.out
@@ -0,0 +1,13 @@
+vlib/v/checker/tests/undefined_type_on_sumtype.vv:1:17: error: unknown type `Token`.
+Did you mean `Ok<[]Token>`?
+    1 | type ParseRes = Result<[]Token, ParseErr>
+      |                 ~~~~~~~~~~~~~~~~~~~~~~~~~
+    2 | 
+    3 | // Token type is unknown
+vlib/v/checker/tests/undefined_type_on_sumtype.vv:30:4: error: unused variable: `rx`
+   28 |     match r {
+   29 |         Some<ParseRes> {
+   30 |             rx := r.value
+      |             ~~
+   31 |         }
+   32 |         None<ParseRes> {}
diff --git a/vlib/v/checker/tests/undefined_type_on_sumtype.vv b/vlib/v/checker/tests/undefined_type_on_sumtype.vv
new file mode 100644
index 0000000000..51b836d89f
--- /dev/null
+++ b/vlib/v/checker/tests/undefined_type_on_sumtype.vv
@@ -0,0 +1,34 @@
+type ParseRes = Result<[]Token, ParseErr>
+
+// Token type is unknown
+//struct Token {}
+
+struct ParseErr {}
+
+type Opt<T> = None<T> | Some<T>
+
+struct None<T> {}
+
+struct Some<T> {
+	value T
+}
+
+type Result<T, U> = Err<U> | Ok<T>
+
+struct Ok<T> {
+	value T
+}
+
+struct Err<U> {
+	value U
+}
+
+fn test_report() {
+	r := Opt<ParseRes>(None<ParseRes>{})
+	match r {
+		Some<ParseRes> {
+			rx := r.value
+		}
+		None<ParseRes> {}
+	}
+}
diff --git a/vlib/v/gen/c/testdata/check_combination_of_alias_and_sumtype.vv b/vlib/v/gen/c/testdata/check_combination_of_alias_and_sumtype.vv
index 7fa58f5183..1271e2b459 100644
--- a/vlib/v/gen/c/testdata/check_combination_of_alias_and_sumtype.vv
+++ b/vlib/v/gen/c/testdata/check_combination_of_alias_and_sumtype.vv
@@ -1,5 +1,7 @@
 type ParseRes = Result<[]Token, ParseErr>
 
+struct Token {}
+
 struct ParseErr {}
 
 type Opt<T> = None<T> | Some<T>