Fix shadowed variable in faiss/impl/ResultHandler.h

Summary:
Our upcoming compiler upgrade will require us not to have shadowed variables. Such variables have a _high_ bug rate and reduce readability, so we would like to avoid them even if the compiler was not forcing us to do so.

This codemod attempts to fix an instance of a shadowed variable. Please review with care: if it's failed the result will be a silent bug.

**What's a shadowed variable?**

Shadowed variables are variables in an inner scope with the same name as another variable in an outer scope. Having the same name for both variables might be semantically correct, but it can make the code confusing to read! It can also hide subtle bugs.

This diff fixes such an issue by renaming the variable.

 - If you approve of this diff, please use the "Accept & Ship" button :-)

Reviewed By: algoriddle

Differential Revision: D52582910

fbshipit-source-id: 92ee06e819f15c411a3fee75a6c9e17fba96a7f3

Author: r-barnes

faiss/impl/ResultHandler.h

@@ -82,10 +82,10 @@ struct HeapResultHandler {
     size_t i0, i1;
 
     /// begin
-    void begin_multiple(size_t i0, size_t i1) {
-        this->i0 = i0;
-        this->i1 = i1;
-        for (size_t i = i0; i < i1; i++) {
+    void begin_multiple(size_t i0_2, size_t i1_2) {
+        this->i0 = i0_2;
+        this->i1 = i1_2;
+        for (size_t i = i0_2; i < i1_2; i++) {
             heap_heapify<C>(k, heap_dis_tab + i * k, heap_ids_tab + i * k);
         }
     }
@@ -231,13 +231,13 @@ struct ReservoirResultHandler {
         size_t i;
 
         /// begin results for query # i
-        void begin(size_t i) {
+        void begin(size_t i_2) {
             res1 = ReservoirTopN<C>(
                     hr.k,
                     hr.capacity,
                     reservoir_dis.data(),
                     reservoir_ids.data());
-            this->i = i;
+            this->i = i_2;
         }
 
         /// add one result for query i
@@ -264,18 +264,18 @@ struct ReservoirResultHandler {
     std::vector<ReservoirTopN<C>> reservoirs;
 
     /// begin
-    void begin_multiple(size_t i0, size_t i1) {
-        this->i0 = i0;
-        this->i1 = i1;
-        reservoir_dis.resize((i1 - i0) * capacity);
-        reservoir_ids.resize((i1 - i0) * capacity);
+    void begin_multiple(size_t i0_2, size_t i1_2) {
+        this->i0 = i0_2;
+        this->i1 = i1_2;
+        reservoir_dis.resize((i1_2 - i0_2) * capacity);
+        reservoir_ids.resize((i1_2 - i0_2) * capacity);
         reservoirs.clear();
-        for (size_t i = i0; i < i1; i++) {
+        for (size_t i = i0_2; i < i1_2; i++) {
             reservoirs.emplace_back(
                     k,
                     capacity,
-                    reservoir_dis.data() + (i - i0) * capacity,
-                    reservoir_ids.data() + (i - i0) * capacity);
+                    reservoir_dis.data() + (i - i0_2) * capacity,
+                    reservoir_ids.data() + (i - i0_2) * capacity);
         }
     }
 
@@ -363,9 +363,9 @@ struct RangeSearchResultHandler {
     int pr = 0;
 
     /// begin
-    void begin_multiple(size_t i0, size_t i1) {
-        this->i0 = i0;
-        this->i1 = i1;
+    void begin_multiple(size_t i0_2, size_t i1_2) {
+        this->i0 = i0_2;
+        this->i1 = i1_2;
     }
 
     /// add results for query i0..i1 and j0..j1
@@ -443,8 +443,8 @@ struct SingleBestResultHandler {
         SingleResultHandler(SingleBestResultHandler& hr) : hr(hr) {}
 
         /// begin results for query # i
-        void begin(const size_t current_idx) {
-            this->current_idx = current_idx;
+        void begin(const size_t current_idx_2) {
+            this->current_idx = current_idx_2;
             min_dis = HUGE_VALF;
             min_idx = -1;
         }
@@ -467,19 +467,19 @@ struct SingleBestResultHandler {
     size_t i0, i1;
 
     /// begin
-    void begin_multiple(size_t i0, size_t i1) {
-        this->i0 = i0;
-        this->i1 = i1;
+    void begin_multiple(size_t i0_2, size_t i1_2) {
+        this->i0 = i0_2;
+        this->i1 = i1_2;
 
-        for (size_t i = i0; i < i1; i++) {
+        for (size_t i = i0_2; i < i1_2; i++) {
             this->dis_tab[i] = HUGE_VALF;
         }
     }
 
     /// add results for query i0..i1 and j0..j1
-    void add_results(size_t j0, size_t j1, const T* dis_tab) {
+    void add_results(size_t j0, size_t j1, const T* dis_tab_2) {
         for (int64_t i = i0; i < i1; i++) {
-            const T* dis_tab_i = dis_tab + (j1 - j0) * (i - i0) - j0;
+            const T* dis_tab_i = dis_tab_2 + (j1 - j0) * (i - i0) - j0;
 
             auto& min_distance = this->dis_tab[i];
             auto& min_index = this->ids_tab[i];