Internals: Defer class extends resolution until link

src/V3LinkDot.cpp

@@ -84,6 +84,12 @@ class LinkNodeMatcherClass final : public VNodeMatcher {
 public:
     bool nodeMatch(const AstNode* nodep) const override { return VN_IS(nodep, Class); }
 };
+class LinkNodeMatcherClassOrPackage final : public VNodeMatcher {
+public:
+    bool nodeMatch(const AstNode* nodep) const override {
+        return VN_IS(nodep, Class) || VN_IS(nodep, Package);
+    }
+};
 class LinkNodeMatcherFTask final : public VNodeMatcher {
 public:
     bool nodeMatch(const AstNode* nodep) const override { return VN_IS(nodep, NodeFTask); }
@@ -2300,6 +2306,23 @@ class LinkDotResolveVisitor final : public VNVisitor {
         UASSERT_OBJ(ifaceTopVarp, nodep, "Can't find interface var ref: " << findName);
         return ifaceTopVarp;
     }
+    VSymEnt* findClassOrPackage(VSymEnt* lookSymp, AstClassOrPackageRef* nodep, bool classOnly,
+                                const string& forWhat) {
+        if (nodep->classOrPackagep()) return m_statep->getNodeSym(nodep->classOrPackagep());
+        VSymEnt* const foundp = lookSymp->findIdFallback(nodep->name());
+        if (foundp) {
+            nodep->classOrPackageNodep(foundp->nodep());
+            return foundp;
+        } else {
+            const string suggest = m_statep->suggestSymFallback(lookSymp, nodep->name(),
+                                                                LinkNodeMatcherClassOrPackage{});
+            nodep->v3error((classOnly ? "Class" : "Package/Class")
+                           << " for '" << forWhat  // extends/implements
+                           << "' not found: " << nodep->prettyNameQ() << '\n'
+                           << (suggest.empty() ? "" : nodep->warnMore() + suggest));
+            return nullptr;
+        }
+    }
     void markAndCheckPinDup(AstPin* nodep, AstNode* refp, const char* whatp) {
         const auto pair = m_usedPins.emplace(refp, nodep);
         if (!pair.second) {
@@ -3812,6 +3835,9 @@ class LinkDotResolveVisitor final : public VNVisitor {
                 if (AstClassOrPackageRef* lookNodep = VN_CAST(dotp->lhsp(), ClassOrPackageRef)) {
                     iterate(lookNodep);
                     cprp = dotp->rhsp();
+                    VSymEnt* const foundp
+                        = findClassOrPackage(lookSymp, lookNodep, false, nodep->verilogKwd());
+                    if (!foundp) return;
                     UASSERT_OBJ(lookNodep->classOrPackagep(), nodep, "Bad package link");
                     lookSymp = m_statep->getNodeSym(lookNodep->classOrPackagep());
                 } else {
@@ -3825,7 +3851,8 @@ class LinkDotResolveVisitor final : public VNVisitor {
                 nodep->v3error("Attempting to extend using non-class");  // LCOV_EXCL_LINE
                 return;
             }
-            VSymEnt* const foundp = lookSymp->findIdFallback(cpackagerefp->name());
+            VSymEnt* const foundp
+                = findClassOrPackage(lookSymp, cpackagerefp, true, nodep->verilogKwd());
             if (foundp) {
                 if (AstClass* const classp = VN_CAST(foundp->nodep(), Class)) {
                     AstPin* paramsp = cpackagerefp->paramsp();
@@ -3850,12 +3877,6 @@ class LinkDotResolveVisitor final : public VNVisitor {
                     return;
                 }
             } else {
-                const string suggest = m_statep->suggestSymFallback(
-                    m_curSymp, cpackagerefp->name(), LinkNodeMatcherClass{});
-                cpackagerefp->v3error(
-                    "Class for '" << nodep->verilogKwd()  // extends/implements
-                                  << "' not found: " << cpackagerefp->prettyNameQ() << '\n'
-                                  << (suggest.empty() ? "" : cpackagerefp->warnMore() + suggest));
                 return;
             }
             if (!nodep->childDTypep()) nodep->v3error("Attempting to extend using non-class");

src/verilog.y

@@ -7227,12 +7227,12 @@ class_typeExtImpOne<nodeExprp>:  // part of IEEE: class_type, where we either ge
                 idAny
         /*mid*/         { /* no nextId as not refing it above this*/ }
         /*cont*/    parameter_value_assignmentClassE
-                        { $$ = new AstClassOrPackageRef{$<fl>1, *$1, $<scp>1, $3};
+                        { $$ = new AstClassOrPackageRef{$<fl>1, *$1, nullptr, $3};
                           $<scp>$ = $<scp>1; }
         |       idCC
         /*mid*/         { /* no nextId as not refing it above this*/ }
         /*cont*/    parameter_value_assignmentClassE
-                        { $$ = new AstClassOrPackageRef{$<fl>1, *$1, $<scp>1, $3};
+                        { $$ = new AstClassOrPackageRef{$<fl>1, *$1, nullptr, $3};
                           $<scp>$ = $<scp>1; }
         //
         //                      // package_sopeIdFollows expanded

test_regress/t/t_class_extends_nf_bad.out

@@ -1,5 +1,9 @@
-%Error: t/t_class_extends_nf_bad.v:10:19: Class for 'extends' not found: 'IsNotFound'
+%Error: t/t_class_extends_nf_bad.v:15:19: Class for 'extends' not found: 'IsNotFound'
                                         : ... Suggested alternative: 'IsFound'
-   10 | class Cls extends IsNotFound;
+   15 | class Cls extends IsNotFound;   
       |                   ^~~~~~~~~~
+%Error: t/t_class_extends_nf_bad.v:18:25: Class for 'extends' not found: 'NotFound2'
+                                        : ... Suggested alternative: 'otFound2'
+   18 | class Cls2 extends Pkg::NotFound2;   
+      |                         ^~~~~~~~~
 %Error: Exiting due to

test_regress/t/t_class_extends_nf_bad.v

@@ -4,10 +4,18 @@
 // any use, without warranty, 2020 by Wilson Snyder.
 // SPDX-License-Identifier: CC0-1.0
 
+package Pkg;
+class otFound2;
+endclass
+endpackage
+
 class IsFound;
 endclass
 
-class Cls extends IsNotFound;
+class Cls extends IsNotFound;  // BAD: not found
+endclass
+
+class Cls2 extends Pkg::NotFound2;  // BAD: not found
 endclass
 
 module t (/*AUTOARG*/);