Commit 187f0c1e262cbeb37d72c571381b5b94c1eb3a63 | zig

Resolves: #19677

2 files changed, 21 insertions(+), 1 deletions(-)

src/Sema.zig+6-1

 @@ -4279,7 +4279,7 @@ fn zirResolveInferredAlloc(sema: *Sema, block: *Block, inst: Zir.Inst.Index) Com
                 const const_ptr_ty = try sema.makePtrTyConst(final_ptr_ty);
                 const new_const_ptr = try mod.getCoerced(Value.fromInterned(ptr_val), const_ptr_ty);
-                // Remap the ZIR oeprand to the resolved pointer value
+                // Remap the ZIR operand to the resolved pointer value
                 sema.inst_map.putAssumeCapacity(inst_data.operand.toIndex().?, Air.internedToRef(new_const_ptr.toIntern()));
                 // Unless the block is comptime, `alloc_inferred` always produces
 @@ -4305,6 +4305,11 @@ fn zirResolveInferredAlloc(sema: *Sema, block: *Block, inst: Zir.Inst.Index) Com
                 .data = .{ .ty = final_ptr_ty },
             });
+            if (ia1.is_const) {
+                // Remap the ZIR operand to the pointer const
+                sema.inst_map.putAssumeCapacity(inst_data.operand.toIndex().?, try sema.makePtrConst(block, ptr));
+            }
             // Now we need to go back over all the store instructions, and do the logic as if
             // the new result ptr type was available.

test/cases/compile_errors/assign_to_constant_destructure.zig created+15

...	@@ -0,0 +1,15 @@
1	export fn a() void {
2	const S = struct {
3	fn b() struct { usize, usize } {
4	return .{ 0, 0 };
5	}
6	};
7	const c, _ = S.b();
8	c += 10;
9	}
10
11	// error
12	// backend=stage2
13	// target=native
14	//
15	// :8:7: error: cannot assign to constant