fix(ctb): N-03 Assert for impossible condition (#3449)

* fix(ctb): N-03 Assert for impossible condition

* fix(ctb): N-04  Confusing else conditions in ProxyAdmin

* chore: Regen bindings

* chore: regen bindings
Co-authored-by: Matthew Slipper <me@matthewslipper.com>

.changeset/chatty-gorillas-search.md

+---
+'@eth-optimism/contracts-bedrock': patch
+---
+
+Uses assert rather than a require statements to check for conditions we believe are unreachable.This is more semantically explicit, and should enable us to more effectively use some advanced analysis methods in our testing.

.changeset/quiet-olives-roll.md

+---
+'@eth-optimism/contracts-bedrock': patch
+---
+
+Use assert statements for unreachable conditions.

packages/contracts-bedrock/contracts/universal/CrossDomainMessenger.sol

@@ -288,8 +288,9 @@ abstract contract CrossDomainMessenger is
         );
 
         if (_isOtherMessenger()) {
-            // Should never happen.
-            require(msg.value == _value, "CrossDomainMessenger: mismatched message value");
+            // This property should always hold when the message is first submitted (as opposed to
+            // being replayed).
+            assert(msg.value == _value);
         } else {
             require(
                 msg.value == 0,

packages/contracts-bedrock/contracts/universal/ProxyAdmin.sol

@@ -248,7 +248,9 @@ contract ProxyAdmin is Owned {
             string memory name = implementationName[_proxy];
             addressManager.setAddress(name, _implementation);
         } else {
-            revert("ProxyAdmin: unknown proxy type");
+            // It should not be possible to retrieve a ProxyType value which is not matched by
+            // one of the previous conditions.
+            assert(false);
         }
     }
 }