Fix bug preventing optionals from being used in ranges or as indices.

releasenotes.md

@@ -25,6 +25,7 @@
 - Prevent methods from using names of properties or fields. #1638
 - b64 / hex data strings can now be used with \` as well.
 - Contracts on generic modules would evaluate too late, sometimes not catching the error until it already occurred elsewhere.
+- Fix bug preventing optionals from being used in ranges or as indices.
 
 ### Stdlib changes
 - Add `io::MultiReader`, `io::MultiWriter`, and `io::TeeReader` structs.

src/compiler/compiler_internal.h

@@ -681,6 +681,7 @@ typedef struct
 	bool end_from_end : 1;
 	bool is_len : 1;
 	bool is_range : 1;
+	bool is_optional : 1;
 	union
 	{
 		struct

src/compiler/sema_casts.c

@@ -607,6 +607,7 @@ bool cast_to_index(SemaContext *context, Expr *index, Type *subscripted_type)
 	Type *type = index->type;
 	RETRY:
 	type = type_flat_distinct_inline(type);
+	type = type_no_optional(type);
 	switch (type->type_kind)
 	{
 		case TYPE_I8:

src/compiler/sema_expr.c

@@ -3043,6 +3043,7 @@ static inline bool sema_expr_analyse_subscript(SemaContext *context, Expr *expr,
 	// Cast to an appropriate type for index.
 	if (!cast_to_index(context, index, subscripted->type)) return false;
 
+	optional |= IS_OPTIONAL(index);
 	// Check range
 	bool remove_from_back = false;
 	if (!sema_slice_index_is_in_range(context, current_type, index, false, start_from_end, &remove_from_back)) return false;
@@ -3149,7 +3150,7 @@ typedef enum RangeEnv
 	RANGE_FLEXIBLE,
 } RangeEnv;
 
-INLINE bool sema_expre_analyse_range_internal(SemaContext *context, Range *range, Type *indexed_type, ArrayIndex len, RangeEnv env)
+INLINE bool sema_expr_analyse_range_internal(SemaContext *context, Range *range, Type *indexed_type, ArrayIndex len, RangeEnv env)
 {
 	Expr *start = exprptr(range->start);
 	ASSERT0(start);
@@ -3160,9 +3161,13 @@ INLINE bool sema_expre_analyse_range_internal(SemaContext *context, Range *range
 
 	if (!cast_to_index(context, start, indexed_type)) return false;
 	if (end && !cast_to_index(context, end, indexed_type)) return false;
-	if (end && end->type != start->type)
+	Type *end_type = end ? type_no_optional(end->type) : NULL;
+	Type *start_type = type_no_optional(start->type);
+	if (end && IS_OPTIONAL(end)) range->is_optional = true;
+	if (IS_OPTIONAL(start)) range->is_optional = true;
+	if (end && end_type != start_type)
 	{
-		Type *common = type_find_max_type(start->type, end->type);
+		Type *common = type_find_max_type(start_type, end_type);
 		if (!common)
 		{
 			SourceSpan span = start->span;
@@ -3316,7 +3321,7 @@ static inline bool sema_expr_analyse_range(SemaContext *context, Range *range, T
 			return true;
 		case RESOLVE_NOT_DONE:
 			range->status = RESOLVE_RUNNING;
-			if (!sema_expre_analyse_range_internal(context, range, indexed_type, len, env))
+			if (!sema_expr_analyse_range_internal(context, range, indexed_type, len, env))
 			{
 				range->status = RESOLVE_NOT_DONE;
 				return false;
@@ -3421,7 +3426,7 @@ static inline bool sema_expr_analyse_slice(SemaContext *context, Expr *expr, Che
 	ArrayIndex length = sema_len_from_expr(subscripted);
 	Range *range = &expr->slice_expr.range;
 	if (!sema_expr_analyse_range(context, range, subscripted->type, length, env)) return false;
-
+	if (range->is_optional) optional = true;
 	if (check == CHECK_VALUE && sema_cast_const(subscripted) && range->range_type == RANGE_CONST_RANGE)
 	{
 		switch (subscripted->const_expr.const_kind)

test/test_suite/slices/slice_optional_index.c3t

@@ -0,0 +1,120 @@
+// #target: macos-x64
+module test;
+
+fn void test()
+{
+	int[] a = { 1, 2, 3 };
+	for (int i = 0; i < 3; i++)
+	{
+		int! b = i == 0 ? SearchResult.MISSING? : i;
+		int[]! y = a[:b];
+		int[]! w = a[b..];
+		int! z = a[b];
+	}
+}
+
+/* #expect: test.ll
+
+  store %"int[]" %1, ptr %a, align 8
+  store i32 0, ptr %i, align 4
+  br label %loop.cond
+
+loop.cond:                                        ; preds = %after_assign15, %entry
+  %2 = load i32, ptr %i, align 4
+  %lt = icmp slt i32 %2, 3
+  br i1 %lt, label %loop.body, label %loop.exit
+
+loop.body:                                        ; preds = %loop.cond
+  %3 = load i32, ptr %i, align 4
+  %eq = icmp eq i32 %3, 0
+  br i1 %eq, label %cond.lhs, label %cond.rhs
+
+cond.lhs:                                         ; preds = %loop.body
+  store i64 ptrtoint (ptr @"std.core.builtin.SearchResult$MISSING" to i64), ptr %b.f, align 8
+  br label %after_assign
+
+cond.rhs:                                         ; preds = %loop.body
+  %4 = load i32, ptr %i, align 4
+  br label %cond.phi
+
+cond.phi:                                         ; preds = %cond.rhs
+  store i32 %4, ptr %b, align 4
+  store i64 0, ptr %b.f, align 8
+  br label %after_assign
+
+after_assign:                                     ; preds = %cond.phi, %cond.lhs
+  %5 = load %"int[]", ptr %a, align 8
+  %6 = extractvalue %"int[]" %5, 0
+  %optval = load i64, ptr %b.f, align 8
+  %not_err = icmp eq i64 %optval, 0
+  %7 = call i1 @llvm.expect.i1(i1 %not_err, i1 true)
+  br i1 %7, label %after_check, label %assign_optional
+
+assign_optional:                                  ; preds = %after_assign
+  store i64 %optval, ptr %y.f, align 8
+  br label %after_assign1
+
+after_check:                                      ; preds = %after_assign
+  %8 = load i32, ptr %b, align 4
+  %sext = sext i32 %8 to i64
+  %add = add i64 0, %sext
+  %size = sub i64 %add, 0
+  %9 = insertvalue %"int[]" undef, ptr %6, 0
+  %10 = insertvalue %"int[]" %9, i64 %size, 1
+  store %"int[]" %10, ptr %y, align 8
+  store i64 0, ptr %y.f, align 8
+  br label %after_assign1
+
+after_assign1:                                    ; preds = %after_check, %assign_optional
+  %11 = load %"int[]", ptr %a, align 8
+  %12 = extractvalue %"int[]" %11, 0
+  %optval2 = load i64, ptr %b.f, align 8
+  %not_err3 = icmp eq i64 %optval2, 0
+  %13 = call i1 @llvm.expect.i1(i1 %not_err3, i1 true)
+  br i1 %13, label %after_check5, label %assign_optional4
+
+assign_optional4:                                 ; preds = %after_assign1
+  store i64 %optval2, ptr %w.f, align 8
+  br label %after_assign8
+
+after_check5:                                     ; preds = %after_assign1
+  %14 = load i32, ptr %b, align 4
+  %sext6 = sext i32 %14 to i64
+  %15 = extractvalue %"int[]" %11, 1
+  %size7 = sub i64 %15, %sext6
+  %ptroffset = getelementptr inbounds [4 x i8], ptr %12, i64 %sext6
+  %16 = insertvalue %"int[]" undef, ptr %ptroffset, 0
+  %17 = insertvalue %"int[]" %16, i64 %size7, 1
+  store %"int[]" %17, ptr %w, align 8
+  store i64 0, ptr %w.f, align 8
+  br label %after_assign8
+
+after_assign8:                                    ; preds = %after_check5, %assign_optional4
+  %18 = load ptr, ptr %a, align 8
+  %optval9 = load i64, ptr %b.f, align 8
+  %not_err10 = icmp eq i64 %optval9, 0
+  %19 = call i1 @llvm.expect.i1(i1 %not_err10, i1 true)
+  br i1 %19, label %after_check12, label %assign_optional11
+
+assign_optional11:                                ; preds = %after_assign8
+  store i64 %optval9, ptr %z.f, align 8
+  br label %after_assign15
+
+after_check12:                                    ; preds = %after_assign8
+  %20 = load i32, ptr %b, align 4
+  %sext13 = sext i32 %20 to i64
+  %ptroffset14 = getelementptr inbounds [4 x i8], ptr %18, i64 %sext13
+  %21 = load i32, ptr %ptroffset14, align 4
+  store i32 %21, ptr %z, align 4
+  store i64 0, ptr %z.f, align 8
+  br label %after_assign15
+
+after_assign15:                                   ; preds = %after_check12, %assign_optional11
+  %22 = load i32, ptr %i, align 4
+  %add16 = add i32 %22, 1
+  store i32 %add16, ptr %i, align 4
+  br label %loop.cond
+
+loop.exit:                                        ; preds = %loop.cond
+  ret void
+}