conditional optional unwrapping

compiler/lower/lower.odin

@@ -633,7 +633,22 @@ lower_statements :: proc(state: ^State, statements: []hir.Stmt_Id) {
 				diagnostic=statement.diagnostic,
 			})
 		case .If:
-			cond := lower_expr(state, statement.expr)
+			// A conditional unwrap (`if opt |v| { ... }`) carries the binding local id in
+			// `statement.local`; `expr` is then the optional, not a bool condition. Test it
+			// for presence, and inside the then-block bind the unwrapped value to the local.
+			is_unwrap := statement.local != hir.INVALID_LOCAL
+			opt := ir.INVALID_INSTRUCTION
+			cond: ir.Instruction_Id
+			if is_unwrap {
+				opt = lower_expr(state, statement.expr)
+				cond = append_instruction(state, ir.Instruction{
+					op=.Optional_Is_Some, span=statement.span, type=types.BOOL,
+					target=ir.INVALID_REF, a=opt, b=ir.INVALID_INSTRUCTION,
+					diagnostic=source.INVALID_DIAGNOSTIC,
+				})
+			} else {
+				cond = lower_expr(state, statement.expr)
+			}
 			has_else := statement.else_body != nil
 			then_lbl := fresh_label(state)
 			else_lbl := fresh_label(state) if has_else else then_lbl
@@ -649,6 +664,26 @@ lower_statements :: proc(state: ^State, statements: []hir.Stmt_Id) {
 				target=ir.INVALID_REF, a=ir.INVALID_INSTRUCTION, b=ir.INVALID_INSTRUCTION,
 				diagnostic=source.INVALID_DIAGNOSTIC,
 			})
+			if is_unwrap && int(statement.local) < len(state.func_locals) {
+				local := state.func_locals[statement.local]
+				slot := append_instruction(state, ir.Instruction{
+					op=.Alloca, span=statement.span, type=local.type,
+					target=ir.local_ref(ir.Local_Id(statement.local)),
+					a=ir.INVALID_INSTRUCTION, b=ir.INVALID_INSTRUCTION,
+					diagnostic=source.INVALID_DIAGNOSTIC,
+				})
+				state.local_slots[statement.local] = slot
+				inner := append_instruction(state, ir.Instruction{
+					op=.Optional_Value, span=statement.span, type=local.type,
+					target=ir.INVALID_REF, a=opt, b=ir.INVALID_INSTRUCTION,
+					diagnostic=source.INVALID_DIAGNOSTIC,
+				})
+				append_instruction(state, ir.Instruction{
+					op=.Store, span=statement.span, type=local.type,
+					target=ir.INVALID_REF, a=slot, b=inner,
+					diagnostic=source.INVALID_DIAGNOSTIC,
+				})
+			}
 			lower_statements(state, statement.then_body)
 			append_instruction(state, ir.Instruction{
 				op=.Br, span=statement.span, type=types.VOID, integer=merge_lbl,