Renamed the tests to be more descriptive.

test/Harper/Tests/Bad/CallingCurrentOnAnEmptyIteratorBeforeNext.har

@@ -0,0 +1,7 @@
+iterate :: Iterator Integer;
+iterate = {
+    yield return;
+};
+
+main :: Integer;
+main = iterate.current;

test/Harper/Tests/Bad/CallingCurrentOnAnEmptyRefIteratorBeforeNext.har

@@ -0,0 +1,8 @@
+iterate :: RefIterator Integer sideeffect;
+iterate = {
+    eval printLn "Empty." ();
+    yield return;
+};
+
+main :: sideeffect -> Integer;
+main = iterate.current ();

test/Harper/Tests/Bad/CallingCurrentOnAnEmptyRefIteratorBeforeNext.out

@@ -0,0 +1,3 @@
+Error: iterator's `current` function called before `next` or the sequence had no elements.
+
+Execution terminated with an error: runtime error.

test/Harper/Tests/Bad/CallingCurrentOnAnIteratorBeforeNext.out

@@ -0,0 +1,3 @@
+Error: iterator's `current` function called before `next` or the sequence had no elements.
+
+Execution terminated with an error: runtime error.

test/Harper/Tests/Bad/CallingCurrentOnAnRefIteratorBeforeNext.har

@@ -0,0 +1,12 @@
+iterate :: RefIterator Integer sideeffect;
+iterate = {
+    var (i :: Integer) = 0;
+    while true {
+        yield i;
+        eval printLn i ();
+        i += 1;
+    }
+};
+
+main :: sideeffect -> Integer;
+main = iterate.current ();

test/Harper/Tests/Bad/CallingCurrentOnAnRefIteratorBeforeNext.out

@@ -0,0 +1,3 @@
+Error: iterator's `current` function called before `next` or the sequence had no elements.
+
+Execution terminated with an error: runtime error.

test/Harper/Tests/Bad/ConflictingVariantDeclarations_BetweenDifferentTypes.har

@@ -0,0 +1,16 @@
+value List a = {
+  variant Empty = { };
+};
+
+value Bag a b c d = {
+  variant Empty = { };
+  variant Bag = {
+    data = {
+      a :: a; a :: b; c :: c; c :: d;
+    }
+  };
+};
+
+
+main :: Integer;
+main = 42;

test/Harper/Tests/Bad/ConflictingVariantDeclarations_BetweenDifferentTypes.out

@@ -0,0 +1,25 @@
+Error: conflicting type variant names `Empty`.
+Conflicting declarations:
+value List a = {
+  variant Empty = {
+    } ;
+  }
+
+Located at line 1 column 1
+value Bag a b c d = {
+  variant Empty = {
+    } ;
+  variant Bag = {
+    data = {
+      a :: a ;
+      a :: b ;
+      c :: c ;
+      c :: d ;
+      }
+    } ;
+  }
+
+Located at line 5 column 1
+
+
+Execution terminated with an error: type error.

test/Harper/Tests/Bad/issue010_conflCtorDecls.har → test/Harper/Tests/Bad/ConflictingVariantDeclarations_Mixed.har

@@ -17,7 +17,7 @@ value List a = {
 
 value Bag a b c d = {
   variant Empty = { };
-  variant Bag = {
+  variant NonEmpty = {
     data = {
       a :: a; a :: b; c :: c; c :: d;
     }

test/Harper/Tests/Bad/issue010_conflCtorDecls.out → test/Harper/Tests/Bad/ConflictingVariantDeclarations_Mixed.out

@@ -1,4 +1,4 @@
-Error: conflicting type variant names `Empty`, `NonEmpty`.
+Error: conflicting type variant names `Empty`, `NonEmpty`, `NonEmpty`.
 Conflicting declarations:
 value List a = {
   variant Empty = {
@@ -20,7 +20,7 @@ Located at line 1 column 1
 value Bag a b c d = {
   variant Empty = {
     } ;
-  variant Bag = {
+  variant NonEmpty = {
     data = {
       a :: a ;
       a :: b ;

test/Harper/Tests/Bad/ConflictingVariantDeclarations_WithinOneType.har

@@ -0,0 +1,28 @@
+value List a = {
+  variant Empty = { };
+
+  variant NonEmpty = {
+    data = {
+      head :: a;
+    }
+  };
+
+  variant NonEmpty = {
+    data = {
+      head :: a;
+      tail :: List a;
+    }
+  };
+};
+
+value Bag a b c d = {
+  variant Bag = {
+    data = {
+      a :: a; a :: b; c :: c; c :: d;
+    }
+  };
+};
+
+
+main :: Integer;
+main = 42;

test/Harper/Tests/Bad/ConflictingVariantDeclarations_WithinOneType.out

@@ -0,0 +1,22 @@
+Error: conflicting type variant names `NonEmpty`.
+Conflicting declarations:
+value List a = {
+  variant Empty = {
+    } ;
+  variant NonEmpty = {
+    data = {
+      head :: a ;
+      }
+    } ;
+  variant NonEmpty = {
+    data = {
+      head :: a ;
+      tail :: List a ;
+      }
+    } ;
+  }
+
+Located at line 1 column 1
+
+
+Execution terminated with an error: type error.

test/Harper/Tests/Bad/DeclaredIdentifiersAreNotInScopeOnRightHandSideOfDeconstruction.har

@@ -0,0 +1,12 @@
+main :: sideeffect -> ();
+main = {
+  // If lambdas could be recursive, i.e. `f` was visible in the body of the deconstructed lambda,
+  // this code would have no sensible semantics, as `f` would be used during the evaluation 
+  // of the value being assigned to it. This restriction could theoretically be dropped if the rhs is pure.
+  (f :: Integer -> Integer) = (\(x :: Integer) => {
+      eval printLn (f 10) ();
+      return (\(n :: Integer) => n * x);
+      }) 42 ();
+
+  eval printLn (f 10) ();
+};

test/Harper/Tests/Bad/issue019_lambdaSE2.out → test/Harper/Tests/Bad/DeclaredIdentifiersAreNotInScopeOnRightHandSideOfDeconstruction.out

@@ -1,6 +1,6 @@
 Error: undeclared identifier `f`.
 During evaluation of:
  f
-Located at line 4 column 21
+Located at line 7 column 21
 
 Execution terminated with an error: type error.

test/Harper/Tests/Good/issue016_ifElseDefiniteAssignment1.har → test/Harper/Tests/Bad/DefiniteAssignment_If.har

@@ -1,15 +1,19 @@
 f :: Integer -> Integer;
 f n = {
   var (x :: Integer);
-
+  var (result :: Integer) = 0;
+
   if (n == 42) {
     x := n;
+
+    // x is definitely assigned.
+
+    result += x;
   }
-  else {
-    x := 0;
-  }
+
+  // x is not definitely assigned.
 
-  (result :: Integer) = x + n;
+  result += x + n;
   return result;
 };
 

test/Harper/Tests/Bad/issue016_definiteAssignment.out → test/Harper/Tests/Bad/DefiniteAssignment_If.out

@@ -1,6 +1,6 @@
 Error: variable `x` is not definitely assigned at point of use.
 During evaluation of:
   x
-Located at line 4 column 10
+Located at line 16 column 13
 
 Execution terminated with an error: type error.

test/Harper/Tests/Bad/DefiniteAssignment_IfElseIf.har

@@ -0,0 +1,28 @@
+f :: Integer -> Integer;
+f n = {
+  var (x :: Integer);
+  var (result :: Integer) = 0;
+
+  if (n == 42) {
+    x := n;
+
+    // x is definitey assigned.
+
+    result += x;
+  }
+  else if (n < 42) {
+    x := 0;
+
+    // x is definitely assigned.
+
+    result += x;
+  }
+
+  // x is not definitely assigned.
+
+  result += x + n;
+  return result;
+};
+
+main :: Integer;
+main = f 42;

test/Harper/Tests/Bad/issue016_ifElseIfDefiniteAssignment.out → test/Harper/Tests/Bad/DefiniteAssignment_IfElseIf.out

@@ -1,6 +1,6 @@
 Error: variable `x` is not definitely assigned at point of use.
 During evaluation of:
   x
-Located at line 12 column 25
+Located at line 23 column 13
 
 Execution terminated with an error: type error.

test/Harper/Tests/Bad/issue013_genPatMatch.har → test/Harper/Tests/Bad/GeneralizingATypeInPatternMatch.har

@@ -12,6 +12,7 @@ g b = {
 h :: a -> b;
 h = {
   match f g {
+    // Object being matched is of type Bool -> Integer. Generalization to c -> d should fail.
     (y :: c -> d) => return y;
   }
 };

test/Harper/Tests/Bad/issue013_genPatMatch.out → test/Harper/Tests/Bad/GeneralizingATypeInPatternMatch.out

@@ -2,7 +2,7 @@ Error: the pattern of type `c& -> d&` cannot be used to match an expression of t
 During evaluation of:
 (y :: c -> d)=> return y ;
 
-Located at line 15 column 5
+Located at line 16 column 5
 
 
 Execution terminated with an error: type error.

test/Harper/Tests/Bad/NonBoolPredicate_While.har

@@ -0,0 +1,10 @@
+f :: Integer -> Integer;
+f n = {
+  while 1 {
+    return n;
+  }
+  return 0;
+};
+
+main :: Integer;
+main = f 42;

test/Harper/Tests/Bad/NonBoolPredicate_While.out

@@ -0,0 +1,9 @@
+Error: expression `1` of type `Integer` cannot be used as a predicate in a conditional. 
+During evaluation of: 
+while 1 { 
+    return n ;
+    }
+
+Located at line 3 column 3
+
+Execution terminated with an error: type error.

test/Harper/Tests/Good/BooleanOperators_LazyAnd.har

@@ -0,0 +1,5 @@
+fun :: Integer -> Bool;
+fun n = fun (n + 1);
+
+main :: Bool;
+main = false and (fun 42);

test/Harper/Tests/Good/BooleanOperators_LazyAnd.out

@@ -0,0 +1 @@
+Execution ended with value: false