Print warning for unnamed return parameters and no return statement

test/libsolidity/syntaxTests/tryCatch/almost_call_options.sol

@@ -11,4 +11,6 @@ contract C {
 // ====
 // EVMVersion: >=byzantium
 // ----
+// Warning 6321: (73-77): Unnamed return variable can remain unassigned. Add an explicit return with value to all non-reverting code paths or name the variable.
+// Warning 6321: (79-83): Unnamed return variable can remain unassigned. Add an explicit return with value to all non-reverting code paths or name the variable.
 // Warning 2072: (122-134): Unused local variable.

test/libsolidity/syntaxTests/tryCatch/catch_error.sol

@@ -8,4 +8,7 @@ contract C {
     }
 }
 // ====
-// EVMVersion: >=byzantium
+// EVMVersion: >=byzantium
+// ----
+// Warning 6321: (46-50): Unnamed return variable can remain unassigned. Add an explicit return with value to all non-reverting code paths or name the variable.
+// Warning 6321: (52-56): Unnamed return variable can remain unassigned. Add an explicit return with value to all non-reverting code paths or name the variable.

test/libsolidity/syntaxTests/tryCatch/catch_error_named.sol

@@ -8,4 +8,7 @@ contract C {
     }
 }
 // ====
-// EVMVersion: >=byzantium
+// EVMVersion: >=byzantium
+// ----
+// Warning 6321: (46-50): Unnamed return variable can remain unassigned. Add an explicit return with value to all non-reverting code paths or name the variable.
+// Warning 6321: (52-56): Unnamed return variable can remain unassigned. Add an explicit return with value to all non-reverting code paths or name the variable.

test/libsolidity/syntaxTests/tryCatch/catch_low_level.sol

@@ -8,4 +8,7 @@ contract C {
     }
 }
 // ====
-// EVMVersion: >=byzantium
+// EVMVersion: >=byzantium
+// ----
+// Warning 6321: (46-50): Unnamed return variable can remain unassigned. Add an explicit return with value to all non-reverting code paths or name the variable.
+// Warning 6321: (52-56): Unnamed return variable can remain unassigned. Add an explicit return with value to all non-reverting code paths or name the variable.

test/libsolidity/syntaxTests/tryCatch/no_returns.sol

@@ -6,4 +6,7 @@ contract C {
 
         }
     }
-}
+}
+// ----
+// Warning 6321: (46-50): Unnamed return variable can remain unassigned. Add an explicit return with value to all non-reverting code paths or name the variable.
+// Warning 6321: (52-56): Unnamed return variable can remain unassigned. Add an explicit return with value to all non-reverting code paths or name the variable.

test/libsolidity/syntaxTests/tryCatch/returns.sol

@@ -8,3 +8,6 @@ contract C {
         }
     }
 }
+// ----
+// Warning 6321: (46-50): Unnamed return variable can remain unassigned. Add an explicit return with value to all non-reverting code paths or name the variable.
+// Warning 6321: (52-56): Unnamed return variable can remain unassigned. Add an explicit return with value to all non-reverting code paths or name the variable.

test/libsolidity/syntaxTests/tryCatch/returns_memory.sol

@@ -9,3 +9,6 @@ contract C {
 }
 // ====
 // EVMVersion: >=byzantium
+// ----
+// Warning 6321: (46-59): Unnamed return variable can remain unassigned. Add an explicit return with value to all non-reverting code paths or name the variable.
+// Warning 6321: (61-65): Unnamed return variable can remain unassigned. Add an explicit return with value to all non-reverting code paths or name the variable.

test/libsolidity/syntaxTests/tryCatch/returns_memory_anonymous.sol

@@ -8,4 +8,7 @@ contract C {
     }
 }
 // ====
-// EVMVersion: >=byzantium
+// EVMVersion: >=byzantium
+// ----
+// Warning 6321: (46-59): Unnamed return variable can remain unassigned. Add an explicit return with value to all non-reverting code paths or name the variable.
+// Warning 6321: (61-65): Unnamed return variable can remain unassigned. Add an explicit return with value to all non-reverting code paths or name the variable.

test/libsolidity/syntaxTests/tryCatch/two_catch_clauses.sol

@@ -11,4 +11,7 @@ contract C {
     }
 }
 // ====
-// EVMVersion: >=byzantium
+// EVMVersion: >=byzantium
+// ----
+// Warning 6321: (46-50): Unnamed return variable can remain unassigned. Add an explicit return with value to all non-reverting code paths or name the variable.
+// Warning 6321: (52-56): Unnamed return variable can remain unassigned. Add an explicit return with value to all non-reverting code paths or name the variable.