Fix ICE when printing an error message related to mappings

test/libsolidity/semanticTests/types/mapping/user_defined_types_mapping_storage.sol

@@ -0,0 +1,28 @@
+type A is uint;
+type B is uint;
+
+library L {
+  function f(mapping(A=>B) storage _m, B _v) public { _m[A.wrap(uint(2))] = _v; }
+  function f(mapping(uint=>uint) storage _m, uint _v) public { _m[uint(3)] = _v; }
+}
+
+contract C {
+	mapping(uint=>uint) uintMap;
+	mapping(A=>B) abMap;
+
+	function testAB() public returns (bool) {
+		L.f(abMap, B.wrap(3));
+		return B.unwrap(abMap[A.wrap(uint(2))]) == 3;
+	}
+	function testUint() public returns (bool) {
+		L.f(uintMap, 4);
+		return uintMap[3] == 4;
+	}
+}
+
+// ====
+// compileViaYul: also
+// ----
+// library: L
+// testAB() -> true
+// testUint() -> true

test/libsolidity/syntaxTests/types/mapping/int_mapping.sol

@@ -0,0 +1,5 @@
+library L {
+  function f(mapping(uint=>uint) memory) public {}
+}
+// ----
+// TypeError 4061: (25-51): Type mapping(uint256 => uint256) is only valid in storage because it contains a (nested) mapping.

test/libsolidity/syntaxTests/types/mapping/user_defined_types_mapping_memory.sol

@@ -0,0 +1,6 @@
+type T is uint;
+library L {
+  function f(mapping(T=>T) memory) public {}
+}
+// ----
+// TypeError 4061: (41-61): Type mapping(T => T) is only valid in storage because it contains a (nested) mapping.