[CS] Always eagerly bind member type var to hole for missing member

We know this is where the issue is so we ought to always produce a
concrete hole.

lib/Sema/CSSimplify.cpp

@@ -11604,22 +11604,11 @@ ConstraintSystem::SolutionKind ConstraintSystem::simplifyMemberConstraint(
             // `key path` constraint can't be retired until all components
             // are simplified.
             addTypeVariableConstraintsToWorkList(memberTypeVar);
-          } else if (isa<Expr *>(locator->getAnchor()) &&
-                     !getSemanticsProvidingParentExpr(
-                         getAsExpr(locator->getAnchor()))) {
-            // If there are no contextual expressions that could provide
-            // a type for the member type variable, let's default it to
-            // a placeholder eagerly so it could be propagated to the
-            // pattern if necessary.
-            recordTypeVariablesAsHoles(memberTypeVar);
-          } else if (locator->isLastElement<LocatorPathElt::PatternMatch>()) {
-            // Let's handle member patterns specifically because they use
-            // equality instead of argument application constraint, so allowing
-            // them to bind member could mean missing valid hole positions in
-            // the pattern.
-            recordTypeVariablesAsHoles(memberTypeVar);
           } else {
-            recordPotentialHole(memberTypeVar);
+            // Eagerly turn the member type variable into a hole since we know
+            // this is where the issue is and we've recorded a fix for it. This
+            // avoids producing unnecessary holes for e.g generic parameters.
+            recordTypeVariablesAsHoles(memberTypeVar);
           }
         }