harec

commit 43b34048dd83bde5d4d2a7d93d37a593a9c12fda
parent f631856549f9d269ccb9b774bb6718292ff83109
Author: Sebastian <sebastian@sebsite.pw>
Date:   Wed, 18 May 2022 23:46:06 -0400

check: only lower rconst if value fits into type

For example, '界' can no longer be cast to a u8, but 'a' still can.

Signed-off-by: Sebastian <sebastian@sebsite.pw>

Diffstat:
M
src/check.c
 | 
31
+++++++++++++++++++++++++++++++

1 file changed, 31 insertions(+), 0 deletions(-)
diff --git a/src/check.c b/src/check.c
@@ -1294,6 +1294,37 @@ check_expr_cast(struct context *ctx,
 				gen_typename(secondary));
 			return;
 		}
+		if (primary->storage == STORAGE_RCONST) {
+			uint32_t max = 0;
+			switch (secondary->storage) {
+			case STORAGE_RUNE:
+			case STORAGE_U64:
+			case STORAGE_I64:
+			case STORAGE_U32:
+				break;
+			case STORAGE_U16:
+				max = UINT16_MAX;
+				break;
+			case STORAGE_I16:
+				max = INT16_MAX;
+				break;
+			case STORAGE_U8:
+				max = UINT8_MAX;
+				break;
+			case STORAGE_I8:
+				max = INT8_MAX;
+				break;
+			default:
+				assert(0); // Invariant
+			}
+
+			if (max != 0 && value->constant.rune > max) {
+				error(ctx, aexpr->cast.type->loc, expr,
+					"Rune does not fit in %s",
+					gen_typename(secondary));
+				return;
+			}
+		}
 		break;
 	}
 	expr->result = aexpr->cast.kind == C_TEST? &builtin_type_bool : secondary;