ir: Implement @TypeOf with multiple arguments

Closes #439

test/compile_errors.zig

@@ -2,6 +2,24 @@ const tests = @import("tests.zig");
 const std = @import("std");
 
 pub fn addCases(cases: *tests.CompileErrorContext) void {
+    cases.addTest("@TypeOf with no arguments",
+        \\export fn entry() void {
+        \\    _ = @TypeOf();
+        \\}
+    , &[_][]const u8{
+        "tmp.zig:2:9: error: expected at least 1 argument, found 0",
+    });
+
+    cases.addTest("@TypeOf with incompatible arguments",
+        \\export fn entry() void {
+        \\    var var_1: f32 = undefined;
+        \\    var var_2: u32 = undefined;
+        \\    _ = @TypeOf(var_1, var_2);
+        \\}
+    , &[_][]const u8{
+        "tmp.zig:4:9: error: incompatible types: 'f32' and 'u32'",
+    });
+
     cases.addTest("type mismatch with tuple concatenation",
         \\export fn entry() void {
         \\    var x = .{};