Overflow-checked addition.

test/libsolidity/semanticTests/viaYul/detect_add_overflow.yul

@@ -0,0 +1,18 @@
+contract C {
+    function f(uint a, uint b) public pure returns (uint x) {
+        x = a + b;
+    }
+    function g(uint8 a, uint8 b) public pure returns (uint8 x) {
+        x = a + b;
+    }
+}
+// ====
+// compileViaYul: true
+// ----
+// f(uint256,uint256): 5, 6 -> 11
+// f(uint256,uint256): -2, 1 -> -1
+// f(uint256,uint256): -2, 2 -> FAILURE
+// f(uint256,uint256): 2, -2 -> FAILURE
+// g(uint8,uint8): 128, 64 -> 192
+// g(uint8,uint8): 128, 127 -> 255
+// g(uint8,uint8): 128, 128 -> FAILURE

test/libsolidity/semanticTests/viaYul/local_address_assignment.sol

@@ -0,0 +1,10 @@
+contract C {
+    function f(address a) public pure returns (address x) {
+        address b = a;
+        x = b;
+    }
+}
+// ====
+// compileViaYul: true
+// ----
+// f(address): 0x1234 -> 0x1234

test/libsolidity/semanticTests/viaYul/local_assignment.sol

@@ -0,0 +1,10 @@
+contract C {
+    function f(uint a) public pure returns (uint x) {
+        uint b = a;
+        x = b;
+    }
+}
+// ====
+// compileViaYul: true
+// ----
+// f(uint256): 6 -> 6

test/libsolidity/semanticTests/viaYul/local_bool_assignment.sol

@@ -0,0 +1,10 @@
+contract C {
+    function f(bool a) public pure returns (bool x) {
+        bool b = a;
+        x = b;
+    }
+}
+// ====
+// compileViaYul: true
+// ----
+// f(bool): true -> true

test/libsolidity/semanticTests/viaYul/simple_assignment.sol

@@ -0,0 +1,10 @@
+contract C {
+    function f(uint a, uint b) public pure returns (uint x, uint y) {
+        x = a;
+        y = b;
+    }
+}
+// ====
+// compileViaYul: true
+// ----
+// f(uint256,uint256): 5, 6 -> 5, 6