From 616fe798c801baa5fa7238f5fc576a5090938999 Mon Sep 17 00:00:00 2001
From: Jimmi Holst Christensen <jimmiholstchristensen@gmail.com>
Date: Sat, 30 Jun 2018 17:35:05 +0200
Subject: [PATCH] Revert "contains_comptime_undefined_value should not follow
 pointers"

This reverts commit 58b1692182dc2f8da5b535f59e9a89cfab10a7b6.
---
 src/analyze.cpp | 72 ++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 71 insertions(+), 1 deletion(-)

diff --git a/src/analyze.cpp b/src/analyze.cpp
index 4c200888d..068ea48c0 100644
--- a/src/analyze.cpp
+++ b/src/analyze.cpp
@@ -5296,6 +5296,41 @@ bool contains_comptime_undefined_value(ConstExprValue *value) {
     switch (value->type->id) {
         case TypeTableEntryIdInvalid:
             zig_unreachable();
+
+        case TypeTableEntryIdPointer: {
+            ConstPtrValue *ptr = &value->data.x_ptr;
+            if (ptr->mut == ConstPtrMutRuntimeVar)
+                return false;
+
+            switch (ptr->special) {
+                case ConstPtrSpecialInvalid:
+                    zig_unreachable();
+                case ConstPtrSpecialRef:
+                    return contains_comptime_undefined_value(ptr->data.ref.pointee);
+                case ConstPtrSpecialBaseArray: {
+                    size_t index = ptr->data.base_array.elem_index;
+                    ConstExprValue *arr = ptr->data.base_array.array_val;
+                    if (arr->special == ConstValSpecialUndef)
+                        return true;
+                    if (arr->data.x_array.special == ConstArraySpecialUndef)
+                        return true;
+
+                    return contains_comptime_undefined_value(&arr->data.x_array.s_none.elements[index]);
+                }
+                case ConstPtrSpecialBaseStruct: {
+                    size_t index = ptr->data.base_struct.field_index;
+                    ConstExprValue *str = ptr->data.base_struct.struct_val;
+                    if (str->special == ConstValSpecialUndef)
+                        return true;
+
+                    return contains_comptime_undefined_value(&str->data.x_struct.fields[index]);
+                }
+                case ConstPtrSpecialFunction: // TODO: Can a fn ptr have an undefined value?
+                case ConstPtrSpecialDiscard:
+                case ConstPtrSpecialHardCodedAddr:
+                    return false;
+            }
+        }
         case TypeTableEntryIdArray: {
             ConstArrayValue *arr = &value->data.x_array;
             if (arr->special == ConstArraySpecialUndef)
@@ -5309,6 +5344,42 @@ bool contains_comptime_undefined_value(ConstExprValue *value) {
         }
         case TypeTableEntryIdStruct: {
             ConstStructValue *str = &value->data.x_struct;
+            if (value->type->data.structure.is_slice) {
+                ConstExprValue *len = &str->fields[slice_len_index];
+                ConstExprValue *ptr = &str->fields[slice_ptr_index];
+                if (len->special == ConstValSpecialUndef)
+                    return true;
+                if (ptr->special == ConstValSpecialUndef)
+                    return true;
+
+                switch (ptr->data.x_ptr.special) {
+                    case ConstPtrSpecialRef:
+                        return contains_comptime_undefined_value(ptr->data.x_ptr.data.ref.pointee);
+                    case ConstPtrSpecialBaseArray: {
+                        size_t offset = ptr->data.x_ptr.data.base_array.elem_index;
+                        ConstExprValue *arr = ptr->data.x_ptr.data.base_array.array_val;
+                        if (arr->special == ConstValSpecialUndef)
+                            return true;
+                        if (arr->data.x_array.special == ConstArraySpecialUndef)
+                            return true;
+
+                        uint64_t slice_len = bigint_as_unsigned(&len->data.x_bigint);
+                        for (size_t i = 0; i < slice_len; ++i) {
+                            if (contains_comptime_undefined_value(&arr->data.x_array.s_none.elements[i + offset]))
+                                return true;
+                        }
+
+                        return false;
+                    }
+                    case ConstPtrSpecialBaseStruct:
+                    case ConstPtrSpecialInvalid:
+                    case ConstPtrSpecialFunction:
+                    case ConstPtrSpecialDiscard:
+                    case ConstPtrSpecialHardCodedAddr:
+                        zig_unreachable();
+                }
+            }
+
             for (size_t i = 0; i < value->type->data.structure.src_field_count; ++i) {
                 if (contains_comptime_undefined_value(&str->fields[i]))
                     return true;
@@ -5329,7 +5400,6 @@ bool contains_comptime_undefined_value(ConstExprValue *value) {
         case TypeTableEntryIdUnion:
             return contains_comptime_undefined_value(value->data.x_union.payload);
 
-        case TypeTableEntryIdPointer:
         case TypeTableEntryIdArgTuple:
         case TypeTableEntryIdVoid:
         case TypeTableEntryIdBool: