diff --git a/test/libsolidity/semanticTests/dirty_calldata_bytes.sol b/test/libsolidity/semanticTests/dirty_calldata_bytes.sol
new file mode 100644
index 000000000..05a3793f6
--- /dev/null
+++ b/test/libsolidity/semanticTests/dirty_calldata_bytes.sol
@@ -0,0 +1,12 @@
+contract C {
+    function f(bytes calldata b) public returns (bool correct) {
+        byte a = b[3];
+        uint r;
+        assembly {
+            r := a
+        }
+        correct = r == (0x64 << 248);
+    }
+}
+// ----
+// f(bytes): 0x20, 0x04, "dead" -> true
\ No newline at end of file
diff --git a/test/libsolidity/semanticTests/dirty_calldata_dynamic_array.sol b/test/libsolidity/semanticTests/dirty_calldata_dynamic_array.sol
new file mode 100644
index 000000000..1c9d7db30
--- /dev/null
+++ b/test/libsolidity/semanticTests/dirty_calldata_dynamic_array.sol
@@ -0,0 +1,12 @@
+contract C {
+    function f(int16[] calldata a) external returns (bool correct) {
+        uint32 x = uint32(a[1]);
+        uint r;
+        assembly {
+            r := x
+        }
+        correct = r == 0x7fff;
+    }
+}
+// ----
+// f(int16[]): 0x20, 0x02, 0x7fff, 0x7fff -> true
\ No newline at end of file
diff --git a/test/libsolidity/semanticTests/dirty_memory_bytes_to_storgage_copy.sol b/test/libsolidity/semanticTests/dirty_memory_bytes_to_storgage_copy.sol
new file mode 100644
index 000000000..8fc6c33ec
--- /dev/null
+++ b/test/libsolidity/semanticTests/dirty_memory_bytes_to_storgage_copy.sol
@@ -0,0 +1,16 @@
+contract C {
+    bytes x;
+    function f() public returns (uint r) {
+        bytes memory m = "tmp";
+        assembly {
+            mstore(m, 8)
+            mstore(add(m, 32), "deadbeef15dead")
+        }
+        x = m;
+        assembly {
+            r := sload(x_slot)
+        }
+    }
+}
+// ----
+// f() -> 0x6465616462656566313564656164000000000000000000000000000000000010
diff --git a/test/libsolidity/semanticTests/viaYul/dirty_calldata_struct.sol b/test/libsolidity/semanticTests/viaYul/dirty_calldata_struct.sol
new file mode 100644
index 000000000..633fc45c6
--- /dev/null
+++ b/test/libsolidity/semanticTests/viaYul/dirty_calldata_struct.sol
@@ -0,0 +1,18 @@
+pragma experimental ABIEncoderV2;
+contract C {
+    struct S {
+        uint16[] m;
+    }
+    function f(S calldata s) public pure returns (bool correct) {
+        int8 x = int8(s.m[0]);
+        uint r;
+        assembly {
+            r := x
+        }
+        correct = r == 0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff80;
+    }
+}
+// ====
+// compileViaYul: true
+// ----
+// f((uint16[])): 0x20, 0x20, 0x01, 0x0180 -> true
diff --git a/test/libsolidity/semanticTests/viaYul/dirty_memory_dynamic_array.sol b/test/libsolidity/semanticTests/viaYul/dirty_memory_dynamic_array.sol
new file mode 100644
index 000000000..36a253b02
--- /dev/null
+++ b/test/libsolidity/semanticTests/viaYul/dirty_memory_dynamic_array.sol
@@ -0,0 +1,18 @@
+contract C {
+    function f() public pure returns (bool correct) {
+        uint8[] memory m = new uint8[](1);
+        assembly {
+            mstore(add(m, 32), 258)
+        }
+        uint8 x = m[0];
+        uint r;
+        assembly {
+            r := x
+        }
+        correct = (m[0] == 0x02) && (r == 0x02);
+    }
+}
+// ====
+// compileViaYul: true
+// ----
+// f() -> true
diff --git a/test/libsolidity/semanticTests/viaYul/dirty_memory_int32.sol b/test/libsolidity/semanticTests/viaYul/dirty_memory_int32.sol
new file mode 100644
index 000000000..f4f0525bd
--- /dev/null
+++ b/test/libsolidity/semanticTests/viaYul/dirty_memory_int32.sol
@@ -0,0 +1,18 @@
+contract C {
+    function f() public pure returns (bool correct) {
+        uint256[1] memory m;
+        assembly {
+            mstore(m, 0xdeadbeef15dead)
+        }
+        int32 x = int32(m[0]);
+        uint r;
+        assembly {
+            r := x
+        }
+        correct = (m[0] == 0xdeadbeef15dead) && (r == (((2 ** 224 - 1) << 32) | 0xef15dead));
+    }
+}
+// ====
+// compileViaYul: true
+// ----
+// f() -> true
diff --git a/test/libsolidity/semanticTests/viaYul/dirty_memory_read.sol b/test/libsolidity/semanticTests/viaYul/dirty_memory_read.sol
deleted file mode 100644
index d03aa489f..000000000
--- a/test/libsolidity/semanticTests/viaYul/dirty_memory_read.sol
+++ /dev/null
@@ -1,15 +0,0 @@
-contract C {
-	function f() public pure returns (uint8 x, bool a, bool b) {
-		uint8[1] memory m;
-		assembly {
-			mstore(m, 257)
-		}
-		x = m[0];
-		a = (m[0] == 0x01);
-		b = (m[0] == 0x0101);
-	}
-}
-// ====
-// compileViaYul: also
-// ----
-// f() -> 1, true, false
diff --git a/test/libsolidity/semanticTests/viaYul/dirty_memory_static_array.sol b/test/libsolidity/semanticTests/viaYul/dirty_memory_static_array.sol
new file mode 100644
index 000000000..4742bae2d
--- /dev/null
+++ b/test/libsolidity/semanticTests/viaYul/dirty_memory_static_array.sol
@@ -0,0 +1,18 @@
+contract C {
+    function f() public pure returns (bool correct) {
+        uint8[1] memory m;
+        assembly {
+            mstore(m, 257)
+        }
+        uint8 x = m[0];
+        uint r;
+        assembly {
+            r := x
+        }
+        correct = (m[0] == 0x01) && (r == 0x01);
+    }
+}
+// ====
+// compileViaYul: true
+// ----
+// f() -> true
diff --git a/test/libsolidity/semanticTests/viaYul/dirty_memory_struct.sol b/test/libsolidity/semanticTests/viaYul/dirty_memory_struct.sol
new file mode 100644
index 000000000..411cbe069
--- /dev/null
+++ b/test/libsolidity/semanticTests/viaYul/dirty_memory_struct.sol
@@ -0,0 +1,22 @@
+contract C {
+    struct S {
+        uint8[] m;
+    }
+    function f() public pure returns (bool correct) {
+        S memory s;
+        s.m = new uint8[](1);
+        assembly {
+            mstore(add(s, 64), 257)
+        }
+        uint8 x = s.m[0];
+        uint r;
+        assembly {
+            r := x
+        }
+        correct = r == 0x01;
+    }
+}
+// ====
+// compileViaYul: true
+// ----
+// f() -> true
diff --git a/test/libsolidity/semanticTests/viaYul/dirty_memory_uint32.sol b/test/libsolidity/semanticTests/viaYul/dirty_memory_uint32.sol
new file mode 100644
index 000000000..a23a566c5
--- /dev/null
+++ b/test/libsolidity/semanticTests/viaYul/dirty_memory_uint32.sol
@@ -0,0 +1,18 @@
+contract C {
+    function f() public pure returns (bool correct) {
+        uint256[1] memory m;
+        assembly {
+            mstore(m, 0xdeadbeef15dead)
+        }
+        uint32 x = uint32(m[0]);
+        uint r;
+        assembly {
+            r := x
+        }
+        correct = (r == 0xef15dead) && (m[0] == 0xdeadbeef15dead);
+    }
+}
+// ====
+// compileViaYul: true
+// ----
+// f() -> true
diff --git a/test/libsolidity/semanticTests/viaYul/storage/dirty_storage_bytes.sol b/test/libsolidity/semanticTests/viaYul/storage/dirty_storage_bytes.sol
new file mode 100644
index 000000000..ea0112fe5
--- /dev/null
+++ b/test/libsolidity/semanticTests/viaYul/storage/dirty_storage_bytes.sol
@@ -0,0 +1,18 @@
+contract C {
+    bytes b;
+    function f() public returns (bool correct) {
+        assembly {
+            sstore(b_slot, or("deadbeef", 0x08))
+        }
+        byte s = b[3];
+        uint r;
+        assembly {
+            r := s
+        }
+        correct = r == (0x64 << 248);
+    }
+}
+// ====
+// compileViaYul: also
+// ----
+// f() -> true
diff --git a/test/libsolidity/semanticTests/viaYul/storage/dirty_storage_bytes_long.sol b/test/libsolidity/semanticTests/viaYul/storage/dirty_storage_bytes_long.sol
new file mode 100644
index 000000000..9cb01d63a
--- /dev/null
+++ b/test/libsolidity/semanticTests/viaYul/storage/dirty_storage_bytes_long.sol
@@ -0,0 +1,20 @@
+contract C {
+    bytes b;
+    function f() public returns (bool correct) {
+        assembly {
+            sstore(b_slot, 0x41)
+            mstore(0, b_slot)
+            sstore(keccak256(0, 0x20), "deadbeefdeadbeefdeadbeefdeadbeef")
+        }
+        byte s = b[31];
+        uint r;
+        assembly {
+            r := s
+        }
+        correct = r == (0x66 << 248);
+    }
+}
+// ====
+// compileViaYul: also
+// ----
+// f() -> true
\ No newline at end of file
diff --git a/test/libsolidity/semanticTests/viaYul/storage/dirty_storage_dynamic_array.sol b/test/libsolidity/semanticTests/viaYul/storage/dirty_storage_dynamic_array.sol
new file mode 100644
index 000000000..bc886b93d
--- /dev/null
+++ b/test/libsolidity/semanticTests/viaYul/storage/dirty_storage_dynamic_array.sol
@@ -0,0 +1,20 @@
+contract C {
+    uint8[] s;
+    function f() public returns (bool correct) {
+        s.push();
+        assembly {
+            mstore(0, s_slot)
+            sstore(keccak256(0, 0x20), 257)
+        }
+        uint8 x = s[0];
+        uint r;
+        assembly {
+            r := x
+        }
+        correct = (s[0] == 0x01) && (r == 0x01);
+    }
+}
+// ====
+// compileViaYul: also
+// ----
+// f() -> true
diff --git a/test/libsolidity/semanticTests/viaYul/storage/dirty_storage_static_array.sol b/test/libsolidity/semanticTests/viaYul/storage/dirty_storage_static_array.sol
new file mode 100644
index 000000000..7d7298fee
--- /dev/null
+++ b/test/libsolidity/semanticTests/viaYul/storage/dirty_storage_static_array.sol
@@ -0,0 +1,18 @@
+contract C {
+    uint8[1] s;
+    function f() public returns (bool correct) {
+        assembly {
+            sstore(s_slot, 257)
+        }
+        uint8 x = s[0];
+        uint r;
+        assembly {
+            r := x
+        }
+        correct = (s[0] == 0x01) && (r == 0x01);
+    }
+}
+// ====
+// compileViaYul: also
+// ----
+// f() -> true
diff --git a/test/libsolidity/semanticTests/viaYul/storage/dirty_storage_struct.sol b/test/libsolidity/semanticTests/viaYul/storage/dirty_storage_struct.sol
new file mode 100644
index 000000000..1cf19c5be
--- /dev/null
+++ b/test/libsolidity/semanticTests/viaYul/storage/dirty_storage_struct.sol
@@ -0,0 +1,23 @@
+contract C {
+    struct S {
+        uint8[] m;
+    }
+    S s;
+    function f() public returns (bool correct) {
+        s.m.push();
+        assembly {
+            mstore(0, s_slot)
+            sstore(keccak256(0, 0x20), 257)
+        }
+        uint8 x = s.m[0];
+        uint r;
+        assembly {
+            r := x
+        }
+        correct = r == 0x01;
+    }
+}
+// ====
+// compileViaYul: also
+// ----
+// f() -> true