diff --git a/.gitignore b/.gitignore
index 3ff328851..ffb7aded0 100644
--- a/.gitignore
+++ b/.gitignore
@@ -11,3 +11,4 @@ cmake-build-*/
 prefix/
 CMakeLists.txt.user
 CMakeUserPresets.json
+.ccls
diff --git a/include/slang/parsing/ParserMetadata.h b/include/slang/parsing/ParserMetadata.h
index 8e1164766..7e82267da 100644
--- a/include/slang/parsing/ParserMetadata.h
+++ b/include/slang/parsing/ParserMetadata.h
@@ -44,6 +44,9 @@ struct SLANG_EXPORT ParserMetadata {
     /// A list of all class declarations parsed.
     std::vector<const syntax::ClassDeclarationSyntax*> classDecls;
 
+    /// A list of all interface port headers parsed.
+    std::vector<const syntax::InterfacePortHeaderSyntax*> interfacePorts;
+
     /// The EOF token, if one has already been consumed by the parser.
     /// Otherwise an empty token.
     Token eofToken;
diff --git a/source/driver/Driver.cpp b/source/driver/Driver.cpp
index 135bc3e69..cf11b3046 100644
--- a/source/driver/Driver.cpp
+++ b/source/driver/Driver.cpp
@@ -612,6 +612,12 @@ bool Driver::parseAllSources() {
                         missing.emplace(name);
                 }
             }
+
+            for (auto intf : meta.interfacePorts) {
+                std::string_view name = intf->nameOrKeyword.valueText();
+                if (knownNames.find(name) == knownNames.end())
+                    missing.emplace(name);
+            }
         };
 
         for (auto& tree : syntaxTrees)
diff --git a/source/parsing/Parser.cpp b/source/parsing/Parser.cpp
index f5ba9ea31..e943c960b 100644
--- a/source/parsing/Parser.cpp
+++ b/source/parsing/Parser.cpp
@@ -234,7 +234,10 @@ PortHeaderSyntax& Parser::parsePortHeader(Token constKeyword, Token direction) {
         if (!constKeyword && peek(1).kind == TokenKind::Dot &&
             peek(2).kind == TokenKind::Identifier && peek(3).kind == TokenKind::Identifier) {
             auto name = consume();
-            return factory.interfacePortHeader(name, parseDotMemberClause());
+            InterfacePortHeaderSyntax* header =
+                &factory.interfacePortHeader(name, parseDotMemberClause());
+            meta.interfacePorts.push_back(header);
+            return *header;
         }
 
         DataTypeSyntax* type;
diff --git a/source/parsing/ParserMetadata.cpp b/source/parsing/ParserMetadata.cpp
index 4921a10f9..e6b9eb644 100644
--- a/source/parsing/ParserMetadata.cpp
+++ b/source/parsing/ParserMetadata.cpp
@@ -45,6 +45,13 @@ class MetadataVisitor : public SyntaxVisitor<MetadataVisitor> {
         visitDefault(syntax);
     }
 
+    void handle(const InterfacePortHeaderSyntax& syntax) {
+        std::string_view name = syntax.nameOrKeyword.valueText();
+        if (name != "" && name != "interface")
+            meta.interfacePorts.push_back(&syntax);
+        visitDefault(syntax);
+    }
+
     void handle(const DefParamSyntax& syntax) {
         meta.hasDefparams = true;
         visitDefault(syntax);