From 4153cbe16d7ed96203d39c8ac059b5be2303e79b Mon Sep 17 00:00:00 2001
From: Christoffer Lerno <christoffer@aegik.com>
Date: Sun, 5 Dec 2021 23:41:45 +0100
Subject: [PATCH] Change semantics of widening.

---
 src/compiler/sema_casts.c                      | 5 +++++
 test/test_suite/expressions/casts/narrowing.c3 | 7 +++++++
 test/test_suite/symbols/various.c3             | 2 +-
 3 files changed, 13 insertions(+), 1 deletion(-)
 create mode 100644 test/test_suite/expressions/casts/narrowing.c3

diff --git a/src/compiler/sema_casts.c b/src/compiler/sema_casts.c
index ad21d1869..95ee1cbfd 100644
--- a/src/compiler/sema_casts.c
+++ b/src/compiler/sema_casts.c
@@ -1107,6 +1107,11 @@ bool cast_implicit(Expr *expr, Type *to_type)
 		}
 	}
 	cast(expr, to_type);
+	// Allow narrowing after widening
+	if (type_is_numeric(to_type) && expr->expr_kind == EXPR_CONST && type_size(expr_canonical) < type_size(to_canonical))
+	{
+		expr->const_expr.narrowable = true;
+	}
 	if (expr->expr_kind == EXPR_CAST) expr->cast_expr.implicit = true;
 	return true;
 }
diff --git a/test/test_suite/expressions/casts/narrowing.c3 b/test/test_suite/expressions/casts/narrowing.c3
new file mode 100644
index 000000000..983d0af78
--- /dev/null
+++ b/test/test_suite/expressions/casts/narrowing.c3
@@ -0,0 +1,7 @@
+fn int main()
+{
+    ushort x;
+    uint y;
+    ushort z = x + (ushort)(0x12);
+    return 0;
+}
\ No newline at end of file
diff --git a/test/test_suite/symbols/various.c3 b/test/test_suite/symbols/various.c3
index 81b42ee3d..6e4ba7ac6 100644
--- a/test/test_suite/symbols/various.c3
+++ b/test/test_suite/symbols/various.c3
@@ -117,7 +117,7 @@ fn void test16()
     int i = 1;
 
     ichar c = 1 ? 'c' : 'd';
-    ichar d = 1 ? 'c' : i;       // #error: 'int' to 'ichar'
+    ichar d = 1 ? 'c' : i;
     ichar e = 1 ? i : 0;         // #error: 'int' to 'ichar'
     int g = 1 ? i : f;          // #error: 'float' to 'int'
     int a = f ? 1 : 0;