From 50ef10eb4963167225f7153dc5165292dbac0046 Mon Sep 17 00:00:00 2001 From: mlugg Date: Thu, 14 Sep 2023 22:52:09 +0100 Subject: [PATCH] Sema: add missing compile error for runtime-known const with comptime-only type When RLS is used to initialize a value with a comptime-only type, the usual "value with comptime-only type depends on runtime control flow" error message isn't hit, because we don't use results from a block. When we reach `make_ptr_const`, we must validate that the value is comptime-known. --- src/Sema.zig | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff --git a/src/Sema.zig b/src/Sema.zig index 06f75a4a14..3fb425ffa7 100644 --- a/src/Sema.zig +++ b/src/Sema.zig @@ -3780,6 +3780,21 @@ fn zirMakePtrConst(sema: *Sema, block: *Block, inst: Zir.Inst.Index) CompileErro return sema.analyzeDeclRef(try anon_decl.finish(elem_ty, store_val, ptr_info.flags.alignment)); } + // If this is already a comptime-mutable allocation, we don't want to emit an error - the stores + // were already performed at comptime! Just make the pointer constant as normal. + implicit_ct: { + const ptr_val = try sema.resolveMaybeUndefVal(alloc) orelse break :implicit_ct; + if (ptr_val.isComptimeMutablePtr(mod)) break :implicit_ct; + return sema.makePtrConst(block, alloc); + } + + if (try sema.typeRequiresComptime(elem_ty)) { + // The value was initialized through RLS, so we didn't detect the runtime condition earlier. + // TODO: source location of runtime control flow + const init_src: LazySrcLoc = .{ .node_offset_bin_rhs = inst_data.src_node }; + return sema.fail(block, init_src, "value with comptime-only type '{}' depends on runtime control flow", .{elem_ty.fmt(mod)}); + } + return sema.makePtrConst(block, alloc); }