lang: core: fmt: Catch printf edge case

lang/core/fmt/printf.go

@@ -169,6 +169,9 @@ func (obj *PrintfFunc) FuncInfer(partialType *types.Type, partialValues []types.
 		if err != nil {
 			return nil, nil, errwrap.Wrapf(err, "could not parse format string")
 		}
+		if a, l := len(typList)-1, len(formatList); a != l {
+			return nil, nil, fmt.Errorf("number of args (%d) doesn't match format string verb count (%d)", a, l)
+		}
 		for i, x := range typList {
 			if i == 0 { // format string
 				continue

lang/interpret_test/TestAstFunc2/printfunificationerr0.txtar

@@ -2,4 +2,4 @@
 import "fmt"
 test fmt.printf("%d%d", 42) {} # should not pass, missing second int
 -- OUTPUT --
-# err: errUnify: type error: str != list: /main.mcl @ 2:1-2:30
+# err: errUnify: func `printf` infer error: number of args (1) doesn't match format string verb count (2)