Commit 9e5cd43e6d

@@ -12399,7 +12399,8 @@ static ZigType *ir_analyze_array_cat(IrAnalyze *ira, IrInstructionBinOp *instruc
         assert(ptr_val->data.x_ptr.special == ConstPtrSpecialBaseArray);
         op1_array_val = ptr_val->data.x_ptr.data.base_array.array_val;
         op1_array_index = ptr_val->data.x_ptr.data.base_array.elem_index;
-        op1_array_end = op1_array_val->type->data.array.len;
+        ConstExprValue *len_val = &op1_val->data.x_struct.fields[slice_len_index];
+        op1_array_end = bigint_as_unsigned(&len_val->data.x_bigint);
     } else {
         ir_add_error(ira, op1,
             buf_sprintf("expected array or C string literal, found '%s'", buf_ptr(&op1->value.type->name)));
@@ -12446,6 +12447,8 @@ static ZigType *ir_analyze_array_cat(IrAnalyze *ira, IrInstructionBinOp *instruc
         op2_array_val = ptr_val->data.x_ptr.data.base_array.array_val;
         op2_array_index = ptr_val->data.x_ptr.data.base_array.elem_index;
         op2_array_end = op2_array_val->type->data.array.len;
+        ConstExprValue *len_val = &op2_val->data.x_struct.fields[slice_len_index];
+        op2_array_end = bigint_as_unsigned(&len_val->data.x_bigint);
     } else {
         ir_add_error(ira, op2,
             buf_sprintf("expected array or C string literal, found '%s'", buf_ptr(&op2->value.type->name)));

@@ -723,3 +723,17 @@ test "comptime pointer cast array and then slice" {
     assert(sliceA[1] == 2);
     assert(sliceB[1] == 2);
 }
+
+test "slice bounds in comptime concatenation" {
+    const bs = comptime blk: {
+        const b = c"11";
+        break :blk b[0..1];
+    };
+    const str = "" ++ bs;
+    assert(str.len == 1);
+    assert(std.mem.eql(u8, str, "1"));
+
+    const str2 = bs ++ "";
+    assert(str2.len == 1);
+    assert(std.mem.eql(u8, str2, "1"));
+}