Add casts to simplehash.h to silence C++ warnings.

Casting the result of palloc etc. to the intended type is more per
project style anyway.

(The fact that cpluspluscheck doesn't notice these problems is
because it doesn't expand any macros, which seems like a troubling
shortcoming.  Don't have a good idea about improving that.)

Back-patch to v13, which is as far as the patch applies cleanly;
doesn't seem worth working harder.

David Geier

Discussion: https://postgr.es/m/aa5d88a3-71f4-3455-11cf-82de0372c941@gmail.com

src/include/lib/simplehash.h

@@ -436,9 +436,9 @@ SH_CREATE(MemoryContext ctx, uint32 nelements, void *private_data)
 	uint64		size;
 
 #ifdef SH_RAW_ALLOCATOR
-	tb = SH_RAW_ALLOCATOR(sizeof(SH_TYPE));
+	tb = (SH_TYPE *) SH_RAW_ALLOCATOR(sizeof(SH_TYPE));
 #else
-	tb = MemoryContextAllocZero(ctx, sizeof(SH_TYPE));
+	tb = (SH_TYPE *) MemoryContextAllocZero(ctx, sizeof(SH_TYPE));
 	tb->ctx = ctx;
 #endif
 	tb->private_data = private_data;
@@ -448,7 +448,7 @@ SH_CREATE(MemoryContext ctx, uint32 nelements, void *private_data)
 
 	SH_COMPUTE_PARAMETERS(tb, size);
 
-	tb->data = SH_ALLOCATE(tb, sizeof(SH_ELEMENT_TYPE) * tb->size);
+	tb->data = (SH_ELEMENT_TYPE *) SH_ALLOCATE(tb, sizeof(SH_ELEMENT_TYPE) * tb->size);
 
 	return tb;
 }
@@ -493,7 +493,7 @@ SH_GROW(SH_TYPE * tb, uint64 newsize)
 	/* compute parameters for new table */
 	SH_COMPUTE_PARAMETERS(tb, newsize);
 
-	tb->data = SH_ALLOCATE(tb, sizeof(SH_ELEMENT_TYPE) * tb->size);
+	tb->data = (SH_ELEMENT_TYPE *) SH_ALLOCATE(tb, sizeof(SH_ELEMENT_TYPE) * tb->size);
 
 	newdata = tb->data;
 
@@ -1059,7 +1059,7 @@ SH_STAT(SH_TYPE * tb)
 	double		fillfactor;
 	uint32		i;
 
-	uint32	   *collisions = palloc0(tb->size * sizeof(uint32));
+	uint32	   *collisions = (uint32 *) palloc0(tb->size * sizeof(uint32));
 	uint32		total_collisions = 0;
 	uint32		max_collisions = 0;
 	double		avg_collisions;