improve type coverage (#24)

.scrutinizer.yml

@@ -1,6 +1,2 @@
 imports:
   - php
-
-tools:
-  external_code_coverage:
-    timeout: 600 # Timeout in seconds.

src/Psl/Arr/first.php

@@ -15,8 +15,6 @@ namespace Psl\Arr;
  * @psalm-return null|Tv
  *
  * @psalm-pure
- *
- * @psalm-suppress MissingReturnType
  */
 function first(array $array)
 {

src/Psl/Arr/random.php

@@ -17,8 +17,6 @@ use Psl\Random;
  * @psalm-param array<Tk, Tv> $values
  *
  * @psalm-return Tv
- *
- * @psalm-suppress MissingReturnType
  */
 function random(array $values)
 {

src/Psl/Gen/product.php

@@ -27,8 +27,6 @@ use Psl\Iter;
  * @psalm-param    list<iterable<Tk, Tv>> $iterables Iterables to combine
  *
  * @psalm-return   iterable<list<Tk>, list<Tv>>
- *
- * @psalm-suppress MixedReturnTypeCoercion
  */
 function product(iterable ...$iterables): iterable
 {

src/Psl/Gen/range.php

@@ -38,8 +38,10 @@ use Psl;
  * @psalm-pure
  *
  * @see https://github.com/vimeo/psalm/issues/2152#issuecomment-533363310
- * @psalm-suppress MixedOperand
  * @psalm-suppress InvalidReturnType
+ * @psalm-suppress InvalidOperand
+ * @psalm-suppress RedundantConditionGivenDocblockType
+ * @psalm-suppress DocblockTypeContradiction
  */
 function range($start, $end, $step = null): Generator
 {
@@ -53,8 +55,10 @@ function range($start, $end, $step = null): Generator
             Psl\invariant($step > 0, 'If start < end, the step must be positive');
         }
 
-        /** @psalm-var T $i */
+        Psl\invariant(is_int($step) || is_float($step), '$step must be either an integer or a float.');
         for ($i = $start; $i <= $end; $i += $step) {
+            Psl\invariant(is_int($i) || is_float($i), '$i must be either an integer or a float.');
+            Psl\invariant(is_int($step) || is_float($step), '$step must be either an integer or a float.');
             yield $i;
         }
     } else {
@@ -65,8 +69,10 @@ function range($start, $end, $step = null): Generator
             Psl\invariant($step < 0, 'If start > end, the step must be negative');
         }
 
-        /** @psalm-var T $i */
+        Psl\invariant(is_int($step) || is_float($step), '$step must be either an integer or a float.');
         for ($i = $start; $i >= $end; $i += $step) {
+            Psl\invariant(is_int($i) || is_float($i), '$i must be either an integer or a float.');
+            Psl\invariant(is_int($step) || is_float($step), '$step must be either an integer or a float.');
             yield $i;
         }
     }

src/Psl/Iter/count.php

@@ -20,17 +20,19 @@ namespace Psl\Iter;
  *      Iter\count(Iter\flatten([[1, 2, 3], [4], [5, 6], [7, 8]]))
  *      => Int(8)
  *
- * @psalm-param iterable $iterable
+ * @psalm-template T
+ *
+ * @psalm-param iterable<T> $iterable
  */
 function count(iterable $iterable): int
 {
     if (\is_countable($iterable)) {
-        /** @var array|\Countable $iterable */
+        /** @var array<array-key, T>|\Countable $iterable */
         return \count($iterable);
     }
 
     $count = 0;
-    /** @psalm-var mixed $_ */
+    /** @psalm-var T $_ */
     foreach ($iterable as $_) {
         ++$count;
     }

src/Psl/Str/levenshtein.php

@@ -19,8 +19,6 @@ use Psl;
  * @return int this function returns the Levenshtein-Distance between the
  *             two argument strings or -1, if one of the argument strings
  *             is longer than the limit of 255 characters
- *
- * @psalm-suppress PossiblyNullArgument
  */
 function levenshtein(string $str1, string $str2, ?int $cost_of_insertion = null, ?int $cost_of_replacement = null, ?int $cost_of_deletion = null): int
 {

src/Psl/Str/trim.php

@@ -9,8 +9,6 @@ namespace Psl\Str;
  *
  * If the optional character mask isn't provided, the following characters will
  * be stripped: space, tab, newline, carriage return, NUL byte, vertical tab.
- *
- * @psalm-suppress NullArgument
  */
 function trim(string $string, ?string $char_mask = null): string
 {

src/Psl/Str/trim_left.php

@@ -9,8 +9,6 @@ namespace Psl\Str;
  *
  * If the optional character mask isn't provided, the following characters will
  * be stripped: space, tab, newline, carriage return, NUL byte, vertical tab.
- *
- * @psalm-suppress NullArgument
  */
 function trim_left(string $string, ?string $char_mask = null): string
 {

src/Psl/Str/trim_right.php

@@ -9,8 +9,6 @@ namespace Psl\Str;
  *
  * If the optional character mask isn't provided, the following characters will
  * be stripped: space, tab, newline, carriage return, NUL byte, vertical tab.
- *
- * @psalm-suppress NullArgument
  */
 function trim_right(string $string, ?string $char_mask = null): string
 {