Merge pull request #18438 from Maxrimus/release/1.25

Release/1.25

[Reviewed by @mppf ]

Cherrypicked commits:
#18428
#18433

Author: Maxrimus

compiler/resolution/virtualDispatch.cpp

@@ -243,6 +243,7 @@ static void addToVirtualMaps(FnSymbol*      pfn,
                              FnSymbol*      cfn) {
 
   FnSymbol* fn = getInstantiatedFunction(pfn, ct, cfn);
+
   resolveOverride(pfn, fn);
 }
 
@@ -285,27 +286,7 @@ static void collectMethods(FnSymbol*               pfn,
           }
         }
         if (possibleSignatureMatch(pfn, cfn) == true) {
-          if (cfn->retTag == RET_PARAM ||
-              cfn->retTag == RET_TYPE) {
-            USR_FATAL_CONT(cfn,
-                           "param default arguments in overridden methods "
-                           "are not yet supported.");
-          } else {
-            methods.push_back(cfn);
-          }
-
-          // check to see if we are using defaulted actual fns
-          // for any of the formals in pfn. If so, make sure the
-          // corresponding ones exist for the child.
-          int nUserFormals = getNumUserFormals(pfn);
-          for (int i = 1; i <= nUserFormals; i++) {
-            ArgSymbol* pformal = getUserFormal(pfn, i);
-            ArgSymbol* cformal = getUserFormal(cfn, i);
-            FnSymbol* pDefFn = findExistingDefaultedActualFn(pfn, pformal);
-            if (pDefFn) {
-              getOrCreateDefaultedActualFn(cfn, cformal);
-            }
-          }
+          methods.push_back(cfn);
         }
       }
     }
@@ -469,6 +450,31 @@ static void resolveOverride(FnSymbol* pfn, FnSymbol* cfn) {
 
     resolveFunction(cfn);
 
+    // check to see if we are using defaulted actual fns
+    // for any of the formals in pfn. If so, make sure the
+    // corresponding ones exist for the child.
+    int nUserFormals = getNumUserFormals(pfn);
+    for (int i = 1; i <= nUserFormals; i++) {
+      ArgSymbol* pFormal = getUserFormal(pfn, i);
+      ArgSymbol* cFormal = getUserFormal(cfn, i);
+      FnSymbol* pDefFn = findExistingDefaultedActualFn(pfn, pFormal);
+      if (pDefFn) {
+        FnSymbol* cDefFn = getOrCreateDefaultedActualFn(cfn, cFormal);
+        if (cDefFn) {
+          if (pFormal->hasFlag(FLAG_INSTANTIATED_PARAM) &&
+              cFormal->hasFlag(FLAG_INSTANTIATED_PARAM)) {
+            USR_FATAL_CONT(cfn, "param default arguments in overridden methods"
+                                " are not yet supported.");
+          }
+          if (pFormal->hasFlag(FLAG_TYPE_VARIABLE) &&
+              cFormal->hasFlag(FLAG_TYPE_VARIABLE)) {
+            USR_FATAL_CONT(cfn, "type default arguments in overridden methods"
+                                " are not yet supported.");
+          }
+        }
+      }
+    }
+
     if (checkOverrides(cfn) &&
         !ignoreOverrides(cfn) &&
         !cfn->hasFlag(FLAG_OVERRIDE)) {

test/functions/default-arguments/default-argument-class-override3b.bad

@@ -0,0 +1,2 @@
+default-argument-class-override3b.chpl:11: error: type default arguments in overridden methods are not yet supported.
+default-argument-class-override3b.chpl:11: error: type default arguments in overridden methods are not yet supported.

test/functions/default-arguments/default-argument-class-override3b.chpl

@@ -0,0 +1,25 @@
+proc f() type { return int; }
+proc g() type { return real; }
+
+class Parent {
+  proc method(type arg = f()) {
+    writeln("in Parent.method arg=", arg:string);
+  }
+}
+
+class Child : Parent {
+  override proc method(type arg = g()) {
+    writeln("in Child.method arg=", arg:string);
+  }
+}
+
+proc main() {
+  var x:Parent = new Child();
+  x.method();
+
+  var y = new Child();
+  y.method();
+
+  var z = new Parent();
+  z.method();
+}

test/functions/default-arguments/default-argument-class-override3b.future

@@ -0,0 +1,11 @@
+bug: dynamically dispatched methods with default type arguments wrong
+
+#15164
+
+This test demonstrates that when methods are dynamically dispatched
+and have type arguments with defaults, the compiler doesn't use the
+default from the method that was chosen dynamically, but the one based
+on the static type.  This is because we implement default arguments
+as methods currently, and can't dynamically dispatch type methods.
+Yet we have to statically invoke the default arguments in order to
+fulfill the `type` nature of the arguments.

test/functions/default-arguments/default-argument-class-override3b.good

@@ -0,0 +1,3 @@
+in Child.method arg=real(64)
+in Child.method arg=real(64)
+in Parent.method arg=int(64)