diff --git a/verible/verilog/formatting/formatter_class_package_test.cc b/verible/verilog/formatting/formatter_class_package_test.cc
index ee45c51..4f65880 100644
--- a/verible/verilog/formatting/formatter_class_package_test.cc
+++ b/verible/verilog/formatting/formatter_class_package_test.cc
@@ -97,14 +97,23 @@
     },
     {
         // Keep space before explicit modport port name
+        // Careful to still properly handle .member_selects.
         "interface\tfoo  ;"
         "modport mp1(input  .a(sig), output  .b(sig));"
+        "modport mp(output .ch0_wr(ch[0].wr), input .ch0_rd(ch[0].rd), "
+        "output .ch1_wr(ch[1].wr.other), input .ch1_rd(ch[1].rd.other));"
         "endinterface",
         "interface foo;\n"
         "  modport mp1(\n"
         "      input .a(sig),\n"
         "      output .b(sig)\n"
         "  );\n"
+        "  modport mp(\n"
+        "      output .ch0_wr(ch[0].wr),\n"
+        "      input .ch0_rd(ch[0].rd),\n"
+        "      output .ch1_wr(ch[1].wr.other),\n"
+        "      input .ch1_rd(ch[1].rd.other)\n"
+        "  );\n"
         "endinterface\n",
     },
     {
diff --git a/verible/verilog/formatting/token-annotator.cc b/verible/verilog/formatting/token-annotator.cc
index 47a8669..81e7b04 100644
--- a/verible/verilog/formatting/token-annotator.cc
+++ b/verible/verilog/formatting/token-annotator.cc
@@ -308,9 +308,11 @@
 
   // TODO(fangism): Never insert trailing spaces before a newline.
 
-  // Modport port name separator, e.g. "input .a("
+  // Modport port name separator, e.g. "input .a(...)". Match only the
+  // leading '.' that is a direct child of kModportSimplePort (the port
+  // name separator itself), not any '.' inside the port's expression
   if (right.TokenEnum() == '.' &&
-      right_context.IsInside(NodeEnum::kModportSimplePort)) {
+      right_context.DirectParentIs(NodeEnum::kModportSimplePort)) {
     return {1, "Space before modport explicit port name '.'"};
   }
 
diff --git a/verible/verilog/formatting/token-annotator_test.cc b/verible/verilog/formatting/token-annotator_test.cc
index df27619..50463f1 100644
--- a/verible/verilog/formatting/token-annotator_test.cc
+++ b/verible/verilog/formatting/token-annotator_test.cc
@@ -2771,6 +2771,19 @@
           {1, SpacingOptions::kUndecided},
       },
 
+      // A '.' nested inside a modport explicit port's parenthesized
+      // expression, e.g. the hierarchical/member select in
+      // ".a(ch[0].wr)", is not the port name separator.
+      {
+          DefaultStyle,
+          {']', "]"},
+          {'.', "."},
+          {/* any context */},
+          {NodeEnum::kModportSimplePort, NodeEnum::kParenGroup,
+           NodeEnum::kHierarchyExtension},
+          {0, SpacingOptions::kUndecided},
+      },
+
       // Handle '->' as a unary prefix expression.
       {
           DefaultStyle,