refactor cast conversion

- delegate cast type and sign resolution to TypeOf conversion
- internal support for injecting data declarations into statements
- fix size and sign of unbased unsized literals used in casts
- avoid generating many unnecessary explicit casts
- support casts which depend on localparams within procedures
- expression traversal correctly visits types within type casts
- fix typeof on expressions of net types
- handle additional edge cases for unsized integer array patterns
- preserve signedness of implicitly flattened unpacked integer arrays

test/basic/integer_array.sv

@@ -1,4 +1,5 @@
 module top;
+    parameter ONE = 1;
     localparam integer A [4] = { 1, 2, 3, 4 };
     localparam byte    B [4] = { 1, 2, 3, 4 };
     localparam bit     C [4] = { 1, 2, 3, 4 };
@@ -8,6 +9,12 @@ module top;
     localparam integer G [4] = '{ 1, 2, 3, 4 };
     localparam byte    H [4] = '{ 1, 2, 3, 4 };
     localparam bit     I [4] = '{ 1, 2, 3, 4 };
+    localparam integer J [4] = { ONE * '0, ONE * '1, 5 * ONE, ONE * 6 };
+    localparam byte    K [4] = { ONE * '0, ONE * '1, 5 * ONE, ONE * 6 };
+    localparam bit     L [4] = { '0, ONE * '1, 5 * ONE, ONE * 6 };
+    localparam integer unsigned M [4] = { ONE * '0, ONE * '1, 5 * ONE, ONE * 6 };
+    localparam byte    unsigned N [4] = { ONE * '0, ONE * '1, 5 * ONE, ONE * 6 };
+    localparam bit     unsigned O [4] = { '0, ONE * '1, 5 * ONE, ONE * 6 };
     initial begin
 `define PRINT(X) \
         $display("%b %2d %2d", {X[0], X[1], X[2], X[3]}, $bits(X), $bits(X[0]));
@@ -20,6 +27,12 @@ module top;
         `PRINT(G);
         `PRINT(H);
         `PRINT(I);
+        `PRINT(J);
+        `PRINT(K);
+        `PRINT(L);
+        `PRINT(M);
+        `PRINT(N);
+        `PRINT(O);
     end
 
     localparam [1:0][0:1] P = '{'{default:'d1}, '{default:'d2}};