Fix trailing comma in named tuples

src/runestone.jl

@@ -337,6 +337,10 @@ function spaces_in_listlike(ctx::Context, node::Node)
         x -> !(JuliaSyntax.is_whitespace(x) || kind(x) === K","),
         @view(kids[(opening_leaf_idx + 1):(closing_leaf_idx - 1)]),
     )
+    first_item_idx = findnext(x -> !(JuliaSyntax.is_whitespace(x) || kind(x) in KSet", ;"), kids, opening_leaf_idx + 1)
+    if first_item_idx >= closing_leaf_idx
+        first_item_idx = nothing
+    end
     last_item_idx = findprev(x -> !(JuliaSyntax.is_whitespace(x) || kind(x) in KSet", ;"), kids, closing_leaf_idx - 1)
     if last_item_idx <= opening_leaf_idx
         last_item_idx = nothing
@@ -354,7 +358,8 @@ function spaces_in_listlike(ctx::Context, node::Node)
     #  - node is a single item tuple which is not from an anonymous fn (Julia-requirement)
     #  - the closing token is not on the same line as the last item (Runic-requirement)
     require_trailing_comma = false
-    if kind(node) === K"tuple" && n_items == 1 && ctx.lineage_kinds[end] !== K"function"
+    if kind(node) === K"tuple" && n_items == 1 && ctx.lineage_kinds[end] !== K"function" &&
+            kind(kids[first_item_idx::Int]) !== K"parameters"
         # TODO: May also have to check for K"where" and K"::" in the lineage above
         require_trailing_comma = true
     elseif kind(node) in KSet"bracescat block"

test/runtests.jl

@@ -261,6 +261,16 @@ end
         @test format_string("f($(sp)a$(sp)...,$(sp))") == "f(a$(sp)...)"
         @test format_string("f($(sp)a$(sp)...;$(sp)b$(sp)...$(sp))") == "f(a$(sp)...; b$(sp)...)"
     end
+    # Named tuples
+    for sp in ("", " ", "  "), a in ("a", "a = 1")
+        @test format_string("($(sp);$(sp)$(a)$(sp))") ==
+            format_string("($(sp);$(sp)$(a)$(sp),$(sp))") == "(; $(a))"
+        for b in ("b", "b = 2")
+            @test format_string("($(sp);$(sp)$(a)$(sp),$(sp)$(b)$(sp))") ==
+                format_string("($(sp);$(sp)$(a)$(sp),$(sp)$(b)$(sp),$(sp))") ==
+                "(; $(a), $(b))"
+        end
+    end
     # Curly (not as extensive testing as tuple/call/dotcall above but the code path is the
     # same)
     for x in ("", "X"), sp in ("", " ", "  "), a in ("A", "<:B", "C <: D"), b in ("E", "<:F", "G <: H")