Disallow str to []int8 casts (#510)

Author: vtereshkov

doc/lang.md

@@ -437,8 +437,8 @@ If a value `s` of type `S` is given where a value `t` of some other type `T` is
 * `S` and `T` are ordinal types
 * `S` and `T` are pointer types and `sizeof(s^) >= sizeof(t^)` and both `S` and `T` don't contain pointers
 * `S` is an interface type and `T` is a type (or a pointer to a type) that was actually converted to `S`
-* `S` is `[]int8` or `[]uint8` and `T` is `str`
-* `S` is `str` and `T` is `[]int8` or `[]uint8`
+* `S` is `[]uint8` and `T` is `str`
+* `S` is `str` and `T` is `[]uint8`
 * `S` is `[]U`, `T` is `[]V` and `U` can be explicitly converted to `V` 
 
 ## Declarations

playground/umka.js

@@ -713,13 +713,13 @@ void doExplicitTypeConv(Compiler *comp, Type *dest, Type **src, Const *constant)
     }
 
     // Dynamic array to string
-    else if ((*src)->kind == TYPE_DYNARRAY && ((*src)->base->kind == TYPE_INT8 || (*src)->base->kind == TYPE_UINT8) && dest->kind == TYPE_STR)
+    else if ((*src)->kind == TYPE_DYNARRAY && (*src)->base->kind == TYPE_UINT8 && dest->kind == TYPE_STR)
     {
         doDynArrayToStrConv(comp, dest, src, constant, false);
     }
 
     // String to dynamic array
-    else if ((*src)->kind == TYPE_STR && dest->kind == TYPE_DYNARRAY && (dest->base->kind == TYPE_INT8 || dest->base->kind == TYPE_UINT8))
+    else if ((*src)->kind == TYPE_STR && dest->kind == TYPE_DYNARRAY && dest->base->kind == TYPE_UINT8)
     {
         doStrToDynArrayConv(comp, dest, src, constant);
     }

src/umka_expr.c

@@ -2072,7 +2072,7 @@ static FORCE_INLINE void doBuiltinMakefromarr(Fiber *fiber, HeapPages *pages, Er
 }
 
 
-// fn makefromstr(src: str): []char | []int8 | []uint8
+// fn makefromstr(src: str): []char | []uint8
 static FORCE_INLINE void doBuiltinMakefromstr(Fiber *fiber, HeapPages *pages, Error *error)
 {
     DynArray *dest  = (DynArray   *)(fiber->top++)->ptrVal;
@@ -2118,7 +2118,7 @@ static FORCE_INLINE void doBuiltinMaketoarr(Fiber *fiber, HeapPages *pages, Erro
 }
 
 
-// fn maketostr(src: char | []char | []int8 | []uint8): str
+// fn maketostr(src: char | []char | []uint8): str
 static FORCE_INLINE void doBuiltinMaketostr(Fiber *fiber, HeapPages *pages, Error *error)
 {
     char *dest = doGetEmptyStr();

src/umka_vm.c

@@ -750,7 +750,7 @@ Hey Hello
 HellHell
 HellHell
 [72 101 108 108 111 44 32 66 114 97 118 101 32 78 101 119 32 87 111 114 108 100 33]
-[72 101 108 108 111 44 32 -48 -76 -48 -72 -48 -78 -48 -67 -47 -117 -48 -71 32 -48 -67 -48 -66 -48 -78 -47 -117 -48 -71 32 -48 -68 -48 -72 -47 -128 33]
+[72 101 108 108 111 44 32 208 180 208 184 208 178 208 189 209 139 208 185 32 208 189 208 190 208 178 209 139 208 185 32 208 188 208 184 209 128 33]
 Hello, Brave New World!
 Hello, дивный новый мир!
 ['P' 'Q'] "PQ" 2 2

tests/expected.log

@@ -73,7 +73,7 @@ fn test3() {
 fn test4() {
     s := "Hello,"
     a := []uint8(s + " Brave New World!")
-    b := []int8(s + " дивный новый мир!")
+    b := []uint8(s + " дивный новый мир!")
     printf("%v\n%v\n", a, b)
     printf("%s\n%s\n", str(a), str(b))
 }