diff --git a/R/aaa-auto.R b/R/aaa-auto.R
index f394c14d47..26adfa5868 100644
--- a/R/aaa-auto.R
+++ b/R/aaa-auto.R
@@ -26,13 +26,14 @@ add_edges_impl <- function(
 ) {
   # Argument checks
   ensure_igraph(graph)
+  edges <- as_igraph_vs(graph, edges)
 
   on.exit(.Call(R_igraph_finalizer))
   # Function call
   res <- .Call(
     R_igraph_add_edges,
     graph,
-    edges
+    edges - 1
   )
 
   res
@@ -354,6 +355,7 @@ get_eids_impl <- function(
 ) {
   # Argument checks
   ensure_igraph(graph)
+  pairs <- as_igraph_vs(graph, pairs)
   directed <- as.logical(directed)
   error <- as.logical(error)
 
@@ -362,7 +364,7 @@ get_eids_impl <- function(
   res <- .Call(
     R_igraph_get_eids,
     graph,
-    pairs,
+    pairs - 1,
     directed,
     error
   )
@@ -7244,7 +7246,7 @@ edgelist_percolation_impl <- function(
   # Function call
   res <- .Call(
     R_igraph_edgelist_percolation,
-    edges
+    edges - 1
   )
 
   res
@@ -8763,6 +8765,7 @@ similarity_dice_pairs_impl <- function(
 ) {
   # Argument checks
   ensure_igraph(graph)
+  pairs <- as_igraph_vs(graph, pairs)
   mode <- switch_igraph_arg(
     mode,
     "out" = 1L,
@@ -8777,7 +8780,7 @@ similarity_dice_pairs_impl <- function(
   res <- .Call(
     R_igraph_similarity_dice_pairs,
     graph,
-    pairs,
+    pairs - 1,
     mode,
     loops
   )
@@ -8883,6 +8886,7 @@ similarity_jaccard_pairs_impl <- function(
 ) {
   # Argument checks
   ensure_igraph(graph)
+  pairs <- as_igraph_vs(graph, pairs)
   mode <- switch_igraph_arg(
     mode,
     "out" = 1L,
@@ -8897,7 +8901,7 @@ similarity_jaccard_pairs_impl <- function(
   res <- .Call(
     R_igraph_similarity_jaccard_pairs,
     graph,
-    pairs,
+    pairs - 1,
     mode,
     loops
   )
diff --git a/R/components.R b/R/components.R
index ffe1459634..5b344c3905 100644
--- a/R/components.R
+++ b/R/components.R
@@ -204,18 +204,15 @@ decompose <- function(
 ) {
   ensure_igraph(graph)
   mode <- igraph_match_arg(mode)
-  mode <- switch(mode, "weak" = 1L, "strong" = 2L)
 
   if (is.na(max.comps)) {
     max.comps <- -1
   }
-  on.exit(.Call(Rx_igraph_finalizer))
-  .Call(
-    Rx_igraph_decompose,
+  decompose_impl(
     graph,
-    as.numeric(mode),
-    as.numeric(max.comps),
-    as.numeric(min.vertices)
+    mode,
+    max.comps,
+    min.vertices
   )
 }
 
diff --git a/R/conversion.R b/R/conversion.R
index 92d10cab6a..0d73ec08d5 100644
--- a/R/conversion.R
+++ b/R/conversion.R
@@ -223,7 +223,6 @@ get.adjacency.dense <- function(
   graph,
   type = c("both", "upper", "lower"),
   attr = NULL,
-  weights = NULL,
   loops = c("once", "twice", "ignore"),
   names = TRUE
 ) {
@@ -243,20 +242,17 @@ get.adjacency.dense <- function(
     )
   }
   loops <- igraph_match_arg(loops)
-  loops <- switch(loops, "ignore" = 0L, "twice" = 1L, "once" = 2L)
-
-  if (!is.null(weights)) {
-    weights <- as.numeric(weights)
+  # Map "ignore" to "none" for get_adjacency_impl
+  if (loops == "ignore") {
+    loops <- "none"
   }
 
   if (is.null(attr)) {
-    on.exit(.Call(Rx_igraph_finalizer))
-    type <- switch(type, "upper" = 0, "lower" = 1, "both" = 2)
-    res <- .Call(
-      Rx_igraph_get_adjacency,
+    # FIXME: Use get_adjacency_impl() also for non-NULL attr
+    res <- get_adjacency_impl(
       graph,
-      as.numeric(type),
-      weights,
+      type,
+      weights = numeric(),
       loops
     )
   } else {
@@ -287,67 +283,33 @@ get.adjacency.sparse <- function(
 
   type <- igraph_match_arg(type)
 
-  vc <- vcount(graph)
-
-  el <- as_edgelist(graph, names = FALSE)
-  use.last.ij <- FALSE
-
-  if (!is.null(attr)) {
+  # Prepare weights parameter
+  if (is.null(attr)) {
+    weights <- numeric()
+  } else {
     attr <- as.character(attr)
     if (!attr %in% edge_attr_names(graph)) {
       cli::cli_abort("No such edge attribute", call = call)
     }
-    value <- edge_attr(graph, name = attr)
-    if (!is.numeric(value) && !is.logical(value)) {
+    weights <- edge_attr(graph, name = attr)
+    if (!is.numeric(weights) && !is.logical(weights)) {
       cli::cli_abort(
         "Matrices must be either numeric or logical, and the edge attribute is not",
         call = call
       )
     }
-  } else {
-    value <- rep(1, nrow(el))
   }
 
-  if (is_directed(graph)) {
-    res <- Matrix::sparseMatrix(
-      dims = c(vc, vc),
-      i = el[, 1],
-      j = el[, 2],
-      x = value,
-      use.last.ij = use.last.ij
-    )
-  } else {
-    if (type == "upper") {
-      ## upper
-      res <- Matrix::sparseMatrix(
-        dims = c(vc, vc),
-        i = pmin(el[, 1], el[, 2]),
-        j = pmax(el[, 1], el[, 2]),
-        x = value,
-        use.last.ij = use.last.ij
-      )
-    } else if (type == "lower") {
-      ## lower
-      res <- Matrix::sparseMatrix(
-        dims = c(vc, vc),
-        i = pmax(el[, 1], el[, 2]),
-        j = pmin(el[, 1], el[, 2]),
-        x = value,
-        use.last.ij = use.last.ij
-      )
-    } else if (type == "both") {
-      ## both
-      res <- Matrix::sparseMatrix(
-        dims = c(vc, vc),
-        i = pmin(el[, 1], el[, 2]),
-        j = pmax(el[, 1], el[, 2]),
-        x = value,
-        symmetric = TRUE,
-        use.last.ij = use.last.ij
-      )
-      res <- as(res, "generalMatrix")
-    }
-  }
+  # Use the library implementation
+  tmp <- get_adjacency_sparse_impl(
+    graph,
+    type,
+    weights,
+    loops = "once"
+  )
+
+  # Convert to proper Matrix object
+  res <- igraph.i.spMatrix(tmp)
 
   if (names && "name" %in% vertex_attr_names(graph)) {
     colnames(res) <- rownames(res) <- V(graph)$name
@@ -427,7 +389,6 @@ as_adjacency_matrix <- function(
       graph,
       type = type,
       attr = attr,
-      weights = NULL,
       names = names,
       loops = "once"
     )
diff --git a/R/flow.R b/R/flow.R
index e569a0e13a..4dd3f697cc 100644
--- a/R/flow.R
+++ b/R/flow.R
@@ -417,12 +417,11 @@ min_cut <- function(
     }
   } else {
     if (value.only) {
-      res <- .Call(
-        Rx_igraph_st_mincut_value,
-        graph,
-        as_igraph_vs(graph, source) - 1,
-        as_igraph_vs(graph, target) - 1,
-        capacity
+      res <- st_mincut_value_impl(
+        graph = graph,
+        source = source,
+        target = target,
+        capacity = capacity
       )
     } else {
       res <- st_mincut_impl(
@@ -526,12 +525,10 @@ vertex_connectivity <- function(
   if (is.null(source) && is.null(target)) {
     vertex_connectivity_impl(graph = graph, checks = checks)
   } else if (!is.null(source) && !is.null(target)) {
-    on.exit(.Call(Rx_igraph_finalizer))
-    .Call(
-      Rx_igraph_st_vertex_connectivity,
-      graph,
-      as_igraph_vs(graph, source) - 1,
-      as_igraph_vs(graph, target) - 1
+    st_vertex_connectivity_impl(
+      graph = graph,
+      source = source,
+      target = target
     )
   } else {
     cli::cli_abort(c(
@@ -631,12 +628,10 @@ edge_connectivity <- function(
   if (is.null(source) && is.null(target)) {
     edge_connectivity_impl(graph = graph, checks = checks)
   } else if (!is.null(source) && !is.null(target)) {
-    on.exit(.Call(Rx_igraph_finalizer))
-    .Call(
-      Rx_igraph_st_edge_connectivity,
-      graph,
-      as_igraph_vs(graph, source) - 1,
-      as_igraph_vs(graph, target) - 1
+    st_edge_connectivity_impl(
+      graph = graph,
+      source = source,
+      target = target
     )
   } else {
     cli::cli_abort(c(
@@ -653,12 +648,10 @@ edge_disjoint_paths <- function(graph, source = NULL, target = NULL) {
   if (is.null(source) || is.null(target)) {
     cli::cli_abort("Both source and target must be given")
   }
-  on.exit(.Call(Rx_igraph_finalizer))
-  .Call(
-    Rx_igraph_edge_disjoint_paths,
-    graph,
-    as_igraph_vs(graph, source) - 1,
-    as_igraph_vs(graph, target) - 1
+  edge_disjoint_paths_impl(
+    graph = graph,
+    source = source,
+    target = target
   )
 }
 
@@ -670,12 +663,10 @@ vertex_disjoint_paths <- function(graph, source = NULL, target = NULL) {
     cli::cli_abort("Both source and target must be given")
   }
 
-  on.exit(.Call(Rx_igraph_finalizer))
-  .Call(
-    Rx_igraph_vertex_disjoint_paths,
-    graph,
-    as_igraph_vs(graph, source) - 1,
-    as_igraph_vs(graph, target) - 1
+  vertex_disjoint_paths_impl(
+    graph = graph,
+    source = source,
+    target = target
   )
 }
 
diff --git a/R/games.R b/R/games.R
index 5e95805757..dd72d790b0 100644
--- a/R/games.R
+++ b/R/games.R
@@ -826,8 +826,9 @@ aging.prefatt.game <- function(
 #' @param n Number of vertices.
 #' @param power The power of the preferential attachment, the default is one,
 #'   i.e. linear preferential attachment.
-#' @param m Numeric constant, the number of edges to add in each time step This
-#'   argument is only used if both `out.dist` and `out.seq` are omitted
+#' @param m Numeric constant, the number of edges to add in each time step,
+#'   defaults to 1.
+#'   This argument is only used if both `out.dist` and `out.seq` are omitted
 #'   or NULL.
 #' @param out.dist Numeric vector, the distribution of the number of edges to
 #'   add in each time step. This argument is only used if the `out.seq`
@@ -911,15 +912,13 @@ sample_pa <- function(
     cli::cli_warn("{.arg m} is zero, graph will be empty.")
   }
 
-  if (is.null(m) && is.null(out.dist) && is.null(out.seq)) {
+  if (is.null(m)) {
     m <- 1
   }
+  m <- as.numeric(m)
 
   n <- as.numeric(n)
   power <- as.numeric(power)
-  if (!is.null(m)) {
-    m <- as.numeric(m)
-  }
   if (!is.null(out.dist)) {
     out.dist <- as.numeric(out.dist)
   }
@@ -943,25 +942,23 @@ sample_pa <- function(
   }
 
   algorithm <- igraph_match_arg(algorithm)
-  algorithm1 <- switch(
+  algorithm_impl <- switch(
     algorithm,
-    "psumtree" = 1,
-    "psumtree-multiple" = 2,
-    "bag" = 0
+    "psumtree" = "psumtree",
+    "psumtree-multiple" = "psumtree_multiple",
+    "bag" = "bag"
   )
 
-  on.exit(.Call(Rx_igraph_finalizer))
-  res <- .Call(
-    Rx_igraph_barabasi_game,
-    n,
-    power,
-    m,
-    out.seq,
-    out.pref,
-    zero.appeal,
-    directed,
-    algorithm1,
-    start.graph
+  res <- barabasi_game_impl(
+    n = n,
+    power = power,
+    m = m,
+    outseq = out.seq,
+    outpref = out.pref,
+    A = zero.appeal,
+    directed = directed,
+    algo = algorithm_impl,
+    start_from = start.graph
   )
 
   if (igraph_opt("add.params")) {
@@ -1415,24 +1412,22 @@ sample_degseq <- function(
   }
 
   # numbers from https://github.com/igraph/igraph/blob/640083c88bf85fd322ff7b748b9b4e16ebe32aa2/include/igraph_constants.h#L94
-  method1 <- switch(
+  method_impl <- switch(
     method,
-    "configuration" = 0,
-    "vl" = 1,
-    "fast.heur.simple" = 2,
-    "configuration.simple" = 3,
-    "edge.switching.simple" = 4
+    "configuration" = "configuration",
+    "vl" = "vl",
+    "fast.heur.simple" = "fast_heur_simple",
+    "configuration.simple" = "configuration_simple",
+    "edge.switching.simple" = "edge_switching_simple"
   )
   if (!is.null(in.deg)) {
     in.deg <- as.numeric(in.deg)
   }
 
-  on.exit(.Call(Rx_igraph_finalizer))
-  res <- .Call(
-    Rx_igraph_degree_sequence_game,
-    as.numeric(out.deg),
-    in.deg,
-    as.numeric(method1)
+  res <- degree_sequence_game_impl(
+    out_deg = out.deg,
+    in_deg = in.deg,
+    method = method_impl
   )
   if (igraph_opt("add.params")) {
     res$name <- "Degree sequence random graph"
@@ -1683,36 +1678,33 @@ sample_pa_age <- function(
     out.seq <- numeric()
   }
 
-  on.exit(.Call(Rx_igraph_finalizer))
   res <- if (is.null(time.window)) {
-    .Call(
-      Rx_igraph_barabasi_aging_game,
-      as.numeric(n),
-      as.numeric(pa.exp),
-      as.numeric(aging.exp),
-      as.numeric(aging.bin),
-      m,
-      out.seq,
-      out.pref,
-      as.numeric(zero.deg.appeal),
-      as.numeric(zero.age.appeal),
-      as.numeric(deg.coef),
-      as.numeric(age.coef),
-      directed
+    barabasi_aging_game_impl(
+      nodes = n,
+      m = m,
+      outseq = out.seq,
+      outpref = out.pref,
+      pa_exp = pa.exp,
+      aging_exp = aging.exp,
+      aging_bin = aging.bin,
+      zero_deg_appeal = zero.deg.appeal,
+      zero_age_appeal = zero.age.appeal,
+      deg_coef = deg.coef,
+      age_coef = age.coef,
+      directed = directed
     )
   } else {
-    .Call(
-      Rx_igraph_recent_degree_aging_game,
-      as.numeric(n),
-      as.numeric(pa.exp),
-      as.numeric(aging.exp),
-      as.numeric(aging.bin),
-      m,
-      out.seq,
-      out.pref,
-      as.numeric(zero.deg.appeal),
-      directed,
-      time.window
+    recent_degree_aging_game_impl(
+      nodes = n,
+      m = m,
+      outseq = out.seq,
+      outpref = out.pref,
+      pa_exp = pa.exp,
+      aging_exp = aging.exp,
+      aging_bin = aging.bin,
+      window = time.window,
+      zero_appeal = zero.deg.appeal,
+      directed = directed
     )
   }
   if (igraph_opt("add.params")) {
@@ -1816,19 +1808,17 @@ sample_traits_callaway <- function(
   pref.matrix = matrix(1, types, types),
   directed = FALSE
 ) {
-  on.exit(.Call(Rx_igraph_finalizer))
-  res <- .Call(
-    Rx_igraph_callaway_traits_game,
-    as.double(nodes),
-    as.double(types),
-    as.double(edge.per.step),
-    as.double(type.dist),
-    matrix(
+  res <- callaway_traits_game_impl(
+    nodes = nodes,
+    types = types,
+    edges_per_step = edge.per.step,
+    type_dist = type.dist,
+    pref_matrix = matrix(
       as.double(pref.matrix),
       types,
       types
     ),
-    as.logical(directed)
+    directed = directed
   )
   if (igraph_opt("add.params")) {
     res$name <- "Trait-based Callaway graph"
@@ -1871,15 +1861,13 @@ sample_traits <- function(
   pref.matrix = matrix(1, types, types),
   directed = FALSE
 ) {
-  on.exit(.Call(Rx_igraph_finalizer))
-  res <- .Call(
-    Rx_igraph_establishment_game,
-    as.double(nodes),
-    as.double(types),
-    as.double(k),
-    as.double(type.dist),
-    matrix(as.double(pref.matrix), types, types),
-    as.logical(directed)
+  res <- establishment_game_impl(
+    nodes = nodes,
+    types = types,
+    k = k,
+    type_dist = type.dist,
+    pref_matrix = matrix(as.double(pref.matrix), types, types),
+    directed = directed
   )
   if (igraph_opt("add.params")) {
     res$name <- "Trait-based growing graph"
@@ -2166,14 +2154,11 @@ asym_pref <- function(
 connect <- function(graph, order, mode = c("all", "out", "in", "total")) {
   ensure_igraph(graph)
   mode <- igraph_match_arg(mode)
-  mode <- switch(mode, "out" = 1, "in" = 2, "all" = 3, "total" = 3)
 
-  on.exit(.Call(Rx_igraph_finalizer))
-  .Call(
-    Rx_igraph_connect_neighborhood,
-    graph,
-    as.numeric(order),
-    as.numeric(mode)
+  connect_neighborhood_impl(
+    graph = graph,
+    order = order,
+    mode = mode
   )
 }
 
@@ -2231,15 +2216,13 @@ sample_smallworld <- function(
   loops = FALSE,
   multiple = FALSE
 ) {
-  on.exit(.Call(Rx_igraph_finalizer))
-  res <- .Call(
-    Rx_igraph_watts_strogatz_game,
-    as.numeric(dim),
-    as.numeric(size),
-    as.numeric(nei),
-    as.numeric(p),
-    as.logical(loops),
-    as.logical(multiple)
+  res <- watts_strogatz_game_impl(
+    dim = dim,
+    size = size,
+    nei = nei,
+    p = p,
+    loops = loops,
+    multiple = multiple
   )
   if (igraph_opt("add.params")) {
     res$name <- "Watts-Strogatz random graph"
@@ -2305,14 +2288,12 @@ sample_last_cit <- function(
   pref = (1:(agebins + 1))^-3,
   directed = TRUE
 ) {
-  on.exit(.Call(Rx_igraph_finalizer))
-  res <- .Call(
-    Rx_igraph_lastcit_game,
-    as.numeric(n),
-    as.numeric(edges),
-    as.numeric(agebins),
-    as.numeric(pref),
-    as.logical(directed)
+  res <- lastcit_game_impl(
+    nodes = n,
+    edges_per_node = edges,
+    agebins = agebins,
+    preference = pref,
+    directed = directed
   )
   if (igraph_opt("add.params")) {
     res$name <- "Random citation graph based on last citation"
@@ -2351,14 +2332,12 @@ sample_cit_types <- function(
   directed = TRUE,
   attr = TRUE
 ) {
-  on.exit(.Call(Rx_igraph_finalizer))
-  res <- .Call(
-    Rx_igraph_cited_type_game,
-    as.numeric(n),
-    as.numeric(edges),
-    as.numeric(types),
-    as.numeric(pref),
-    as.logical(directed)
+  res <- cited_type_game_impl(
+    nodes = n,
+    types = types,
+    pref = pref,
+    edges_per_step = edges,
+    directed = directed
   )
   if (attr) {
     V(res)$type <- types
@@ -2402,14 +2381,12 @@ sample_cit_cit_types <- function(
   attr = TRUE
 ) {
   pref[] <- as.numeric(pref)
-  on.exit(.Call(Rx_igraph_finalizer))
-  res <- .Call(
-    Rx_igraph_citing_cited_type_game,
-    as.numeric(n),
-    as.numeric(types),
-    pref,
-    as.numeric(edges),
-    as.logical(directed)
+  res <- citing_cited_type_game_impl(
+    nodes = n,
+    types = types,
+    pref = pref,
+    edges_per_step = edges,
+    directed = directed
   )
   if (attr) {
     V(res)$type <- types
diff --git a/R/interface.R b/R/interface.R
index ef105e8921..f1f1f3b0f5 100644
--- a/R/interface.R
+++ b/R/interface.R
@@ -549,15 +549,15 @@ get_edge_ids <- function(graph, vp, directed = TRUE, error = FALSE) {
 
   vp <- el_to_vec(vp, call = rlang::caller_env())
 
-  on.exit(.Call(Rx_igraph_finalizer))
-  .Call(
-    Rx_igraph_get_eids,
-    graph,
-    as_igraph_vs(graph, vp) - 1,
-    as.logical(directed),
-    as.logical(error)
-  ) +
-    1
+  with_igraph_opt(
+    list(return.vs.es = FALSE),
+    get_eids_impl(
+      graph,
+      as_igraph_vs(graph, vp),
+      directed,
+      error
+    )
+  )
 }
 
 #' Find the edge ids based on the incident vertices of the edges
diff --git a/R/make.R b/R/make.R
index dba86b4f4a..a3fa21b0a6 100644
--- a/R/make.R
+++ b/R/make.R
@@ -83,15 +83,13 @@ graph <- function(
       }
 
       old_graph <- function(edges, n = max(edges), directed = TRUE) {
-        on.exit(.Call(Rx_igraph_finalizer))
         if (missing(n) && (is.null(edges) || length(edges) == 0)) {
           n <- 0
         }
-        .Call(
-          Rx_igraph_create,
-          as.numeric(edges) - 1,
-          as.numeric(n),
-          as.logical(directed)
+        create_impl(
+          edges - 1,
+          n,
+          directed
         )
       }
 
@@ -210,15 +208,13 @@ graph.famous <- function(
       }
 
       old_graph <- function(edges, n = max(edges), directed = TRUE) {
-        on.exit(.Call(Rx_igraph_finalizer))
         if (missing(n) && (is.null(edges) || length(edges) == 0)) {
           n <- 0
         }
-        .Call(
-          Rx_igraph_create,
-          as.numeric(edges) - 1,
-          as.numeric(n),
-          as.logical(directed)
+        create_impl(
+          edges - 1,
+          n,
+          directed
         )
       }
 
@@ -289,13 +285,11 @@ line.graph <- function(graph) {
 graph.ring <- function(n, directed = FALSE, mutual = FALSE, circular = TRUE) {
   # nocov start
   lifecycle::deprecate_soft("2.1.0", "graph.ring()", "make_ring()")
-  on.exit(.Call(Rx_igraph_finalizer))
-  res <- .Call(
-    Rx_igraph_ring,
-    as.numeric(n),
-    as.logical(directed),
-    as.logical(mutual),
-    as.logical(circular)
+  res <- ring_impl(
+    n,
+    directed,
+    mutual,
+    circular
   )
   if (igraph_opt("add.params")) {
     res$name <- "Ring graph"
@@ -319,14 +313,11 @@ graph.tree <- function(n, children = 2, mode = c("out", "in", "undirected")) {
   # nocov start
   lifecycle::deprecate_soft("2.1.0", "graph.tree()", "make_tree()")
   mode <- igraph_match_arg(mode)
-  mode1 <- switch(mode, "out" = 0, "in" = 1, "undirected" = 2)
 
-  on.exit(.Call(Rx_igraph_finalizer))
-  res <- .Call(
-    Rx_igraph_kary_tree,
-    as.numeric(n),
-    as.numeric(children),
-    as.numeric(mode1)
+  res <- kary_tree_impl(
+    n,
+    children,
+    mode
   )
   if (igraph_opt("add.params")) {
     res$name <- "Tree"
@@ -354,14 +345,11 @@ graph.star <- function(
   # nocov start
   lifecycle::deprecate_soft("2.1.0", "graph.star()", "make_star()")
   mode <- igraph_match_arg(mode)
-  mode1 <- switch(mode, "out" = 0, "in" = 1, "undirected" = 2, "mutual" = 3)
 
-  on.exit(.Call(Rx_igraph_finalizer))
-  res <- .Call(
-    Rx_igraph_star,
-    as.numeric(n),
-    as.numeric(mode1),
-    as.numeric(center) - 1
+  res <- star_impl(
+    n,
+    mode,
+    center - 1
   )
   if (igraph_opt("add.params")) {
     res$name <- switch(mode, "in" = "In-star", "out" = "Out-star", "Star")
@@ -573,12 +561,10 @@ graph.full.bipartite <- function(
 graph.full <- function(n, directed = FALSE, loops = FALSE) {
   # nocov start
   lifecycle::deprecate_soft("2.1.0", "graph.full()", "make_full_graph()")
-  on.exit(.Call(Rx_igraph_finalizer))
-  res <- .Call(
-    Rx_igraph_full,
-    as.numeric(n),
-    as.logical(directed),
-    as.logical(loops)
+  res <- full_impl(
+    n,
+    directed,
+    loops
   )
   if (igraph_opt("add.params")) {
     res$name <- "Full graph"
@@ -1502,15 +1488,13 @@ make_graph <- function(
       }
 
       old_graph <- function(edges, n = max(edges), directed = TRUE) {
-        on.exit(.Call(Rx_igraph_finalizer))
         if (missing(n) && (is.null(edges) || length(edges) == 0)) {
           n <- 0
         }
-        .Call(
-          Rx_igraph_create,
-          as.numeric(edges) - 1,
-          as.numeric(n),
-          as.logical(directed)
+        create_impl(
+          edges - 1,
+          n,
+          directed
         )
       }
 
@@ -1878,14 +1862,11 @@ make_star <- function(
   center = 1
 ) {
   mode <- igraph_match_arg(mode)
-  mode1 <- switch(mode, "out" = 0, "in" = 1, "undirected" = 2, "mutual" = 3)
 
-  on.exit(.Call(Rx_igraph_finalizer))
-  res <- .Call(
-    Rx_igraph_star,
-    as.numeric(n),
-    as.numeric(mode1),
-    as.numeric(center) - 1
+  res <- star_impl(
+    n,
+    mode,
+    center - 1
   )
   if (igraph_opt("add.params")) {
     res$name <- switch(mode, "in" = "In-star", "out" = "Out-star", "Star")
@@ -1917,12 +1898,10 @@ star <- function(n, mode = c("in", "out", "mutual", "undirected"), center = 1) {
 #' make_full_graph(5)
 #' print_all(make_full_graph(4, directed = TRUE))
 make_full_graph <- function(n, directed = FALSE, loops = FALSE) {
-  on.exit(.Call(Rx_igraph_finalizer))
-  res <- .Call(
-    Rx_igraph_full,
-    as.numeric(n),
-    as.logical(directed),
-    as.logical(loops)
+  res <- full_impl(
+    n,
+    directed,
+    loops
   )
   if (igraph_opt("add.params")) {
     res$name <- "Full graph"
@@ -2067,13 +2046,11 @@ lattice <- function(
 #' print_all(make_ring(10))
 #' print_all(make_ring(10, directed = TRUE, mutual = TRUE))
 make_ring <- function(n, directed = FALSE, mutual = FALSE, circular = TRUE) {
-  on.exit(.Call(Rx_igraph_finalizer))
-  res <- .Call(
-    Rx_igraph_ring,
-    as.numeric(n),
-    as.logical(directed),
-    as.logical(mutual),
-    as.logical(circular)
+  res <- ring_impl(
+    n,
+    directed,
+    mutual,
+    circular
   )
   if (igraph_opt("add.params")) {
     res$name <- "Ring graph"
@@ -2191,14 +2168,11 @@ wheel <- function(
 #' make_tree(10, 3, mode = "undirected")
 make_tree <- function(n, children = 2, mode = c("out", "in", "undirected")) {
   mode <- igraph_match_arg(mode)
-  mode1 <- switch(mode, "out" = 0, "in" = 1, "undirected" = 2)
-
-  on.exit(.Call(Rx_igraph_finalizer))
-  res <- .Call(
-    Rx_igraph_kary_tree,
-    as.numeric(n),
-    as.numeric(children),
-    as.numeric(mode1)
+
+  res <- kary_tree_impl(
+    n,
+    children,
+    mode
   )
   if (igraph_opt("add.params")) {
     res$name <- "Tree"
diff --git a/R/other.R b/R/other.R
index 2db5af9584..7ea550f56e 100644
--- a/R/other.R
+++ b/R/other.R
@@ -132,13 +132,7 @@ sample_seq <- function(low, high, length) {
     cli::cli_abort("length too big for this interval")
   }
 
-  on.exit(.Call(Rx_igraph_finalizer))
-  .Call(
-    Rx_igraph_random_sample,
-    as.numeric(low),
-    as.numeric(high),
-    as.numeric(length)
-  )
+  random_sample_impl(low, high, length)
 }
 
 #' Common handler for vertex type arguments in igraph functions
diff --git a/man/ba.game.Rd b/man/ba.game.Rd
index bcd3f83ee7..3dc6fd7a47 100644
--- a/man/ba.game.Rd
+++ b/man/ba.game.Rd
@@ -23,8 +23,9 @@ ba.game(
 \item{power}{The power of the preferential attachment, the default is one,
 i.e. linear preferential attachment.}
 
-\item{m}{Numeric constant, the number of edges to add in each time step This
-argument is only used if both \code{out.dist} and \code{out.seq} are omitted
+\item{m}{Numeric constant, the number of edges to add in each time step,
+defaults to 1.
+This argument is only used if both \code{out.dist} and \code{out.seq} are omitted
 or NULL.}
 
 \item{out.dist}{Numeric vector, the distribution of the number of edges to
diff --git a/man/barabasi.game.Rd b/man/barabasi.game.Rd
index 142526d7d7..83f4f46db9 100644
--- a/man/barabasi.game.Rd
+++ b/man/barabasi.game.Rd
@@ -23,8 +23,9 @@ barabasi.game(
 \item{power}{The power of the preferential attachment, the default is one,
 i.e. linear preferential attachment.}
 
-\item{m}{Numeric constant, the number of edges to add in each time step This
-argument is only used if both \code{out.dist} and \code{out.seq} are omitted
+\item{m}{Numeric constant, the number of edges to add in each time step,
+defaults to 1.
+This argument is only used if both \code{out.dist} and \code{out.seq} are omitted
 or NULL.}
 
 \item{out.dist}{Numeric vector, the distribution of the number of edges to
diff --git a/man/sample_pa.Rd b/man/sample_pa.Rd
index c7c6608bcd..46098ad14d 100644
--- a/man/sample_pa.Rd
+++ b/man/sample_pa.Rd
@@ -37,8 +37,9 @@ pa(
 \item{power}{The power of the preferential attachment, the default is one,
 i.e. linear preferential attachment.}
 
-\item{m}{Numeric constant, the number of edges to add in each time step This
-argument is only used if both \code{out.dist} and \code{out.seq} are omitted
+\item{m}{Numeric constant, the number of edges to add in each time step,
+defaults to 1.
+This argument is only used if both \code{out.dist} and \code{out.seq} are omitted
 or NULL.}
 
 \item{out.dist}{Numeric vector, the distribution of the number of edges to
diff --git a/tests/testthat/_snaps/aaa-auto.md b/tests/testthat/_snaps/aaa-auto.md
index 754b76eac8..b0266a65fc 100644
--- a/tests/testthat/_snaps/aaa-auto.md
+++ b/tests/testthat/_snaps/aaa-auto.md
@@ -26,7 +26,7 @@
 # add_edges_impl basic
 
     Code
-      add_edges_impl(graph = g, edges = c(0, 1, 1, 2))
+      add_edges_impl(graph = g, edges = c(1, 2, 2, 3))
     Output
       IGRAPH D--- 3 2 -- 
       + edges:
@@ -4547,9 +4547,8 @@
     Code
       edgelist_percolation_impl(edges = "a")
     Condition
-      Error in `edgelist_percolation_impl()`:
-      ! Expected numeric or integer vector, got type 16. Invalid value
-      Source: <file>:<line>
+      Error in `edges - 1`:
+      ! non-numeric argument to binary operator
 
 # is_clique_impl basic
 
@@ -5329,7 +5328,7 @@
       similarity_dice_pairs_impl(graph = g, pairs = matrix(c(1, 2, 2, 3), ncol = 2),
       mode = "in", loops = TRUE)
     Output
-      [1] 0.6666667 0.8000000
+      [1] 0.8000000 0.6666667
 
 # similarity_dice_pairs_impl errors
 
@@ -5428,7 +5427,7 @@
       similarity_jaccard_pairs_impl(graph = g, pairs = matrix(c(1, 2, 2, 3), ncol = 2),
       mode = "in", loops = TRUE)
     Output
-      [1] 0.5000000 0.6666667
+      [1] 0.6666667 0.5000000
 
 # similarity_jaccard_pairs_impl errors
 
diff --git a/tests/testthat/_snaps/conversion.md b/tests/testthat/_snaps/conversion.md
index 2f981abe68..a7afcea593 100644
--- a/tests/testthat/_snaps/conversion.md
+++ b/tests/testthat/_snaps/conversion.md
@@ -95,3 +95,318 @@
       Error in `graph_from_edgelist()`:
       ! Cannot create a graph object because the edgelist contains NAs.
 
+# as_adjacency_matrix() comprehensive snapshot tests
+
+    Code
+      as_adjacency_matrix(g_dir_unwt, sparse = TRUE)
+    Output
+      3 x 3 sparse Matrix of class "dgCMatrix"
+                
+      [1,] . 1 .
+      [2,] . 1 1
+      [3,] 1 . .
+
+---
+
+    Code
+      as_adjacency_matrix(g_dir_unwt, type = "upper", sparse = TRUE)
+    Output
+      3 x 3 sparse Matrix of class "dgCMatrix"
+                
+      [1,] . 1 .
+      [2,] . 1 1
+      [3,] 1 . .
+
+---
+
+    Code
+      as_adjacency_matrix(g_dir_unwt, type = "lower", sparse = TRUE)
+    Output
+      3 x 3 sparse Matrix of class "dgCMatrix"
+                
+      [1,] . 1 .
+      [2,] . 1 1
+      [3,] 1 . .
+
+---
+
+    Code
+      as_adjacency_matrix(g_dir_unwt, sparse = FALSE)
+    Output
+           [,1] [,2] [,3]
+      [1,]    0    1    0
+      [2,]    0    1    1
+      [3,]    1    0    0
+
+---
+
+    Code
+      as_adjacency_matrix(g_dir_unwt, type = "upper", sparse = FALSE)
+    Output
+           [,1] [,2] [,3]
+      [1,]    0    1    0
+      [2,]    0    1    1
+      [3,]    1    0    0
+
+---
+
+    Code
+      as_adjacency_matrix(g_dir_unwt, type = "lower", sparse = FALSE)
+    Output
+           [,1] [,2] [,3]
+      [1,]    0    1    0
+      [2,]    0    1    1
+      [3,]    1    0    0
+
+---
+
+    Code
+      as_adjacency_matrix(g_dir_wt, attr = "weight", sparse = TRUE)
+    Output
+      3 x 3 sparse Matrix of class "dgCMatrix"
+                      
+      [1,] .   1.5 .  
+      [2,] .   0.5 2.3
+      [3,] 3.7 .   .  
+
+---
+
+    Code
+      as_adjacency_matrix(g_dir_wt, attr = "weight", type = "upper", sparse = TRUE)
+    Output
+      3 x 3 sparse Matrix of class "dgCMatrix"
+                      
+      [1,] .   1.5 .  
+      [2,] .   0.5 2.3
+      [3,] 3.7 .   .  
+
+---
+
+    Code
+      as_adjacency_matrix(g_dir_wt, attr = "weight", type = "lower", sparse = TRUE)
+    Output
+      3 x 3 sparse Matrix of class "dgCMatrix"
+                      
+      [1,] .   1.5 .  
+      [2,] .   0.5 2.3
+      [3,] 3.7 .   .  
+
+---
+
+    Code
+      as_adjacency_matrix(g_dir_wt, attr = "weight", sparse = FALSE)
+    Output
+           [,1] [,2] [,3]
+      [1,]  0.0  1.5  0.0
+      [2,]  0.0  0.5  2.3
+      [3,]  3.7  0.0  0.0
+
+---
+
+    Code
+      as_adjacency_matrix(g_dir_wt, attr = "weight", type = "upper", sparse = FALSE)
+    Output
+           [,1] [,2] [,3]
+      [1,]  0.0  1.5  0.0
+      [2,]  0.0  0.5  2.3
+      [3,]  3.7  0.0  0.0
+
+---
+
+    Code
+      as_adjacency_matrix(g_dir_wt, attr = "weight", type = "lower", sparse = FALSE)
+    Output
+           [,1] [,2] [,3]
+      [1,]  0.0  1.5  0.0
+      [2,]  0.0  0.5  2.3
+      [3,]  3.7  0.0  0.0
+
+---
+
+    Code
+      as_adjacency_matrix(g_undir_unwt, sparse = TRUE)
+    Output
+      3 x 3 sparse Matrix of class "dgCMatrix"
+                
+      [1,] . 1 1
+      [2,] 1 . 1
+      [3,] 1 1 .
+
+---
+
+    Code
+      as_adjacency_matrix(g_undir_unwt, type = "upper", sparse = TRUE)
+    Output
+      3 x 3 sparse Matrix of class "dgCMatrix"
+                
+      [1,] . 1 1
+      [2,] . . 1
+      [3,] . . .
+
+---
+
+    Code
+      as_adjacency_matrix(g_undir_unwt, type = "lower", sparse = TRUE)
+    Output
+      3 x 3 sparse Matrix of class "dgCMatrix"
+                
+      [1,] . . .
+      [2,] 1 . .
+      [3,] 1 1 .
+
+---
+
+    Code
+      as_adjacency_matrix(g_undir_unwt, type = "both", sparse = TRUE)
+    Output
+      3 x 3 sparse Matrix of class "dgCMatrix"
+                
+      [1,] . 1 1
+      [2,] 1 . 1
+      [3,] 1 1 .
+
+---
+
+    Code
+      as_adjacency_matrix(g_undir_unwt, sparse = FALSE)
+    Output
+           [,1] [,2] [,3]
+      [1,]    0    1    1
+      [2,]    1    0    1
+      [3,]    1    1    0
+
+---
+
+    Code
+      as_adjacency_matrix(g_undir_unwt, type = "upper", sparse = FALSE)
+    Output
+           [,1] [,2] [,3]
+      [1,]    0    1    1
+      [2,]    0    0    1
+      [3,]    0    0    0
+
+---
+
+    Code
+      as_adjacency_matrix(g_undir_unwt, type = "lower", sparse = FALSE)
+    Output
+           [,1] [,2] [,3]
+      [1,]    0    0    0
+      [2,]    1    0    0
+      [3,]    1    1    0
+
+---
+
+    Code
+      as_adjacency_matrix(g_undir_unwt, type = "both", sparse = FALSE)
+    Output
+           [,1] [,2] [,3]
+      [1,]    0    1    1
+      [2,]    1    0    1
+      [3,]    1    1    0
+
+---
+
+    Code
+      as_adjacency_matrix(g_undir_wt, attr = "weight", sparse = TRUE)
+    Output
+      3 x 3 sparse Matrix of class "dgCMatrix"
+                      
+      [1,] .   2.1 3.2
+      [2,] 2.1 .   4.3
+      [3,] 3.2 4.3 .  
+
+---
+
+    Code
+      as_adjacency_matrix(g_undir_wt, attr = "weight", type = "upper", sparse = TRUE)
+    Output
+      3 x 3 sparse Matrix of class "dgCMatrix"
+                    
+      [1,] . 2.1 3.2
+      [2,] . .   4.3
+      [3,] . .   .  
+
+---
+
+    Code
+      as_adjacency_matrix(g_undir_wt, attr = "weight", type = "lower", sparse = TRUE)
+    Output
+      3 x 3 sparse Matrix of class "dgCMatrix"
+                    
+      [1,] .   .   .
+      [2,] 2.1 .   .
+      [3,] 3.2 4.3 .
+
+---
+
+    Code
+      as_adjacency_matrix(g_undir_wt, attr = "weight", type = "both", sparse = TRUE)
+    Output
+      3 x 3 sparse Matrix of class "dgCMatrix"
+                      
+      [1,] .   2.1 3.2
+      [2,] 2.1 .   4.3
+      [3,] 3.2 4.3 .  
+
+---
+
+    Code
+      as_adjacency_matrix(g_undir_wt, attr = "weight", sparse = FALSE)
+    Output
+           [,1] [,2] [,3]
+      [1,]  0.0  2.1  3.2
+      [2,]  2.1  0.0  4.3
+      [3,]  3.2  4.3  0.0
+
+---
+
+    Code
+      as_adjacency_matrix(g_undir_wt, attr = "weight", type = "upper", sparse = FALSE)
+    Output
+           [,1] [,2] [,3]
+      [1,]    0  2.1  3.2
+      [2,]    0  0.0  4.3
+      [3,]    0  0.0  0.0
+
+---
+
+    Code
+      as_adjacency_matrix(g_undir_wt, attr = "weight", type = "lower", sparse = FALSE)
+    Output
+           [,1] [,2] [,3]
+      [1,]  0.0  0.0    0
+      [2,]  2.1  0.0    0
+      [3,]  3.2  4.3    0
+
+---
+
+    Code
+      as_adjacency_matrix(g_undir_wt, attr = "weight", type = "both", sparse = FALSE)
+    Output
+           [,1] [,2] [,3]
+      [1,]  0.0  2.1  3.2
+      [2,]  2.1  0.0  4.3
+      [3,]  3.2  4.3  0.0
+
+---
+
+    Code
+      as_adjacency_matrix(g_named, sparse = TRUE)
+    Output
+      3 x 3 sparse Matrix of class "dgCMatrix"
+        A B C
+      A . 1 .
+      B . 1 1
+      C 1 . .
+
+---
+
+    Code
+      as_adjacency_matrix(g_named, sparse = FALSE)
+    Output
+        A B C
+      A 0 1 0
+      B 0 1 1
+      C 1 0 0
+
diff --git a/tests/testthat/_snaps/games.md b/tests/testthat/_snaps/games.md
index 8b30cb2190..56ba3f0533 100644
--- a/tests/testthat/_snaps/games.md
+++ b/tests/testthat/_snaps/games.md
@@ -3,7 +3,7 @@
     Code
       sample_degseq(exponential_degrees, method = "vl")
     Condition
-      Error in `sample_degseq()`:
+      Error in `degree_sequence_game_impl()`:
       ! Cannot make a connected graph from the given degree sequence. Invalid value
       Source: <file>:<line>
 
@@ -12,7 +12,7 @@
     Code
       sample_degseq(powerlaw_degrees, method = "vl")
     Condition
-      Error in `sample_degseq()`:
+      Error in `degree_sequence_game_impl()`:
       ! Cannot realize the given degree sequence as an undirected, simple graph. Invalid value
       Source: <file>:<line>
 
diff --git a/tests/testthat/test-aaa-auto.R b/tests/testthat/test-aaa-auto.R
index 466ef44604..ce6b4f6fcf 100644
--- a/tests/testthat/test-aaa-auto.R
+++ b/tests/testthat/test-aaa-auto.R
@@ -57,13 +57,13 @@ test_that("add_edges_impl basic", {
 
   expect_snapshot(add_edges_impl(
     graph = g,
-    edges = c(0, 1, 1, 2)
+    edges = c(1, 2, 2, 3)
   ))
 
   # Structured tests
   result <- add_edges_impl(
     graph = g,
-    edges = c(0, 1, 1, 2)
+    edges = c(1, 2, 2, 3)
   )
   expect_s3_class(result, "igraph")
   expect_equal(vcount(result), 3)
@@ -11761,8 +11761,8 @@ test_that("union_many_impl basic", {
   withr::local_seed(20250909)
   local_igraph_options(print.id = FALSE)
   g1 <- empty_impl(n = 3)
-  g2 <- add_edges_impl(g1, c(0, 1, 1, 2))
-  g3 <- add_edges_impl(g1, c(0, 2))
+  g2 <- add_edges_impl(g1, c(0, 1, 1, 2) + 1)
+  g3 <- add_edges_impl(g1, c(0, 2) + 1)
 
   expect_snapshot(union_many_impl(
     graphs = list(g1, g2, g3)
@@ -11779,9 +11779,9 @@ test_that("union_many_impl basic", {
 test_that("intersection_many_impl basic", {
   withr::local_seed(20250909)
   local_igraph_options(print.id = FALSE)
-  g1 <- add_edges_impl(empty_impl(n = 3), c(0, 1, 1, 2, 0, 2))
-  g2 <- add_edges_impl(empty_impl(n = 3), c(0, 1, 1, 2))
-  g3 <- add_edges_impl(empty_impl(n = 3), c(0, 1))
+  g1 <- add_edges_impl(empty_impl(n = 3), c(0, 1, 1, 2, 0, 2) + 1)
+  g2 <- add_edges_impl(empty_impl(n = 3), c(0, 1, 1, 2) + 1)
+  g3 <- add_edges_impl(empty_impl(n = 3), c(0, 1) + 1)
 
   expect_snapshot(intersection_many_impl(
     graphs = list(g1, g2, g3)
diff --git a/tests/testthat/test-conversion.R b/tests/testthat/test-conversion.R
index 65a2858fc6..aa767e1568 100644
--- a/tests/testthat/test-conversion.R
+++ b/tests/testthat/test-conversion.R
@@ -703,3 +703,166 @@ test_that("graph_from_data_frame works with factors", {
   expect_true(is.factor(V(g)$gender))
   expect_true(is.factor(g_actors$gender))
 })
+
+test_that("as_adjacency_matrix() comprehensive snapshot tests", {
+  # Directed, unweighted, sparse
+  g_dir_unwt <- make_graph(c(1, 2, 2, 3, 3, 1, 2, 2), directed = TRUE)
+  expect_snapshot(as_adjacency_matrix(g_dir_unwt, sparse = TRUE))
+  expect_snapshot(as_adjacency_matrix(
+    g_dir_unwt,
+    type = "upper",
+    sparse = TRUE
+  ))
+  expect_snapshot(as_adjacency_matrix(
+    g_dir_unwt,
+    type = "lower",
+    sparse = TRUE
+  ))
+
+  # Directed, unweighted, dense
+  expect_snapshot(as_adjacency_matrix(g_dir_unwt, sparse = FALSE))
+  expect_snapshot(as_adjacency_matrix(
+    g_dir_unwt,
+    type = "upper",
+    sparse = FALSE
+  ))
+  expect_snapshot(as_adjacency_matrix(
+    g_dir_unwt,
+    type = "lower",
+    sparse = FALSE
+  ))
+
+  # Directed, weighted, sparse
+  g_dir_wt <- g_dir_unwt
+  E(g_dir_wt)$weight <- c(1.5, 2.3, 3.7, 0.5)
+  expect_snapshot(as_adjacency_matrix(g_dir_wt, attr = "weight", sparse = TRUE))
+  expect_snapshot(as_adjacency_matrix(
+    g_dir_wt,
+    attr = "weight",
+    type = "upper",
+    sparse = TRUE
+  ))
+  expect_snapshot(as_adjacency_matrix(
+    g_dir_wt,
+    attr = "weight",
+    type = "lower",
+    sparse = TRUE
+  ))
+
+  # Directed, weighted, dense
+  expect_snapshot(as_adjacency_matrix(
+    g_dir_wt,
+    attr = "weight",
+    sparse = FALSE
+  ))
+  expect_snapshot(as_adjacency_matrix(
+    g_dir_wt,
+    attr = "weight",
+    type = "upper",
+    sparse = FALSE
+  ))
+  expect_snapshot(as_adjacency_matrix(
+    g_dir_wt,
+    attr = "weight",
+    type = "lower",
+    sparse = FALSE
+  ))
+
+  # Undirected, unweighted, sparse
+  g_undir_unwt <- as_undirected(
+    make_graph(c(1, 2, 2, 3, 3, 1)),
+    mode = "collapse"
+  )
+  expect_snapshot(as_adjacency_matrix(g_undir_unwt, sparse = TRUE))
+  expect_snapshot(as_adjacency_matrix(
+    g_undir_unwt,
+    type = "upper",
+    sparse = TRUE
+  ))
+  expect_snapshot(as_adjacency_matrix(
+    g_undir_unwt,
+    type = "lower",
+    sparse = TRUE
+  ))
+  expect_snapshot(as_adjacency_matrix(
+    g_undir_unwt,
+    type = "both",
+    sparse = TRUE
+  ))
+
+  # Undirected, unweighted, dense
+  expect_snapshot(as_adjacency_matrix(g_undir_unwt, sparse = FALSE))
+  expect_snapshot(as_adjacency_matrix(
+    g_undir_unwt,
+    type = "upper",
+    sparse = FALSE
+  ))
+  expect_snapshot(as_adjacency_matrix(
+    g_undir_unwt,
+    type = "lower",
+    sparse = FALSE
+  ))
+  expect_snapshot(as_adjacency_matrix(
+    g_undir_unwt,
+    type = "both",
+    sparse = FALSE
+  ))
+
+  # Undirected, weighted, sparse
+  g_undir_wt <- g_undir_unwt
+  E(g_undir_wt)$weight <- c(2.1, 3.2, 4.3)
+  expect_snapshot(as_adjacency_matrix(
+    g_undir_wt,
+    attr = "weight",
+    sparse = TRUE
+  ))
+  expect_snapshot(as_adjacency_matrix(
+    g_undir_wt,
+    attr = "weight",
+    type = "upper",
+    sparse = TRUE
+  ))
+  expect_snapshot(as_adjacency_matrix(
+    g_undir_wt,
+    attr = "weight",
+    type = "lower",
+    sparse = TRUE
+  ))
+  expect_snapshot(as_adjacency_matrix(
+    g_undir_wt,
+    attr = "weight",
+    type = "both",
+    sparse = TRUE
+  ))
+
+  # Undirected, weighted, dense
+  expect_snapshot(as_adjacency_matrix(
+    g_undir_wt,
+    attr = "weight",
+    sparse = FALSE
+  ))
+  expect_snapshot(as_adjacency_matrix(
+    g_undir_wt,
+    attr = "weight",
+    type = "upper",
+    sparse = FALSE
+  ))
+  expect_snapshot(as_adjacency_matrix(
+    g_undir_wt,
+    attr = "weight",
+    type = "lower",
+    sparse = FALSE
+  ))
+  expect_snapshot(as_adjacency_matrix(
+    g_undir_wt,
+    attr = "weight",
+    type = "both",
+    sparse = FALSE
+  ))
+
+  # With vertex names
+  g_named <- g_dir_unwt
+  V(g_named)$name <- c("A", "B", "C")
+  expect_snapshot(as_adjacency_matrix(g_named, sparse = TRUE))
+  expect_snapshot(as_adjacency_matrix(g_named, sparse = FALSE))
+})
diff --git a/tests/testthat/test-interface.R b/tests/testthat/test-interface.R
index ff287fbb0a..e08493d979 100644
--- a/tests/testthat/test-interface.R
+++ b/tests/testthat/test-interface.R
@@ -248,3 +248,19 @@ test_that("invalidate_cache errors on invalid input", {
   expect_error(invalidate_cache("not a graph"))
   expect_error(invalidate_cache(123))
 })
+
+test_that("get_edge_ids() returns numeric vector, not igraph.es", {
+  g <- make_full_graph(10)
+  mat <- matrix(c(1, 2, 1, 3, 1, 4), 3, 2, byrow = TRUE)
+  result <- get_edge_ids(g, mat)
+  expect_true(is.numeric(result))
+  expect_false(inherits(result, "igraph.es"))
+  expect_equal(result, c(1, 2, 3))
+})
+
+test_that("get_edge_ids() returns 0 for missing edges when error=FALSE", {
+  g <- make_empty_graph(10)
+  result <- get_edge_ids(g, c(1, 2), error = FALSE)
+  expect_equal(result, 0)
+  expect_true(is.numeric(result))
+})
diff --git a/tools/stimulus/functions-R.yaml b/tools/stimulus/functions-R.yaml
index 018d397c6f..c381baaf85 100644
--- a/tools/stimulus/functions-R.yaml
+++ b/tools/stimulus/functions-R.yaml
@@ -519,6 +519,14 @@ igraph_full_bipartite:
 
 igraph_decompose:
 
+#######################################
+# Percolation
+#######################################
+
+igraph_edgelist_percolation:
+    # VERTEX_INDEX_PAIRS has a dependency that we don't have here
+    PARAMS: INDEX_PAIRS edges, OUT VECTOR_INT giant_size, OUT VECTOR_INT vertex_count
+
 #######################################
 # Cliques
 #######################################
diff --git a/tools/stimulus/types-RC.yaml b/tools/stimulus/types-RC.yaml
index 1fcb29b8f5..7c362dba58 100644
--- a/tools/stimulus/types-RC.yaml
+++ b/tools/stimulus/types-RC.yaml
@@ -627,6 +627,18 @@ VERTEX_INDEX_PAIRS:
             igraph_vector_int_destroy(&%C%);
             IGRAPH_FINALLY_CLEAN(1);
 
+INDEX_PAIRS:
+    CALL: '&%C%'
+    CTYPE: igraph_vector_int_t
+    INCONV:
+        IN: |-
+            Rz_SEXP_to_vector_int_copy(%I%, &%C%);
+            IGRAPH_FINALLY(igraph_vector_int_destroy, &%C%);
+    OUTCONV:
+        IN: |-
+            igraph_vector_int_destroy(&%C%);
+            IGRAPH_FINALLY_CLEAN(1);
+
 EDGE_INDICES:
     CALL: '&%C%'
     CTYPE: igraph_vector_int_t
diff --git a/tools/stimulus/types-RR.yaml b/tools/stimulus/types-RR.yaml
index 73ff47ae80..cb52f5cd26 100644
--- a/tools/stimulus/types-RR.yaml
+++ b/tools/stimulus/types-RR.yaml
@@ -276,6 +276,13 @@ VERTEX_INDICES_PV:
               %I% <- create_vs(%I1%, %I%)
             }
 
+VERTEX_INDEX_PAIRS:
+    CALL: '%I% - 1'
+    INCONV: '%I% <- as_igraph_vs(%I1%, %I%)'
+
+INDEX_PAIRS:
+    CALL: '%I% - 1'
+
 EDGE_INDICES:
     CALL: '%I% - 1'
     DEFAULT: