Merge pull request 'fix-nil-void-type' (#36) from fix-nil-void-type into main

Reviewed-on: sashakoshka/fspl#36

analyzer/assignment.go

@@ -36,15 +36,19 @@ func (this *Tree) canAssign (
 	fail := func () error {
 		switch mode {
 		case strict:
-			return errors.Errorf(pos, "expected %v", destination)
+			return errors.Errorf (
+				pos, "expected %v",
+				entity.FormatType(destination))
 		case weak:
 			return errors.Errorf (
 				pos, "cannot use %v as %v",
-				source, destination)
+				entity.FormatType(source),
+				entity.FormatType(destination))
 		case structural: 
 			return errors.Errorf (
 				pos, "cannot convert from %v to %v",
-				source, destination)
+				entity.FormatType(source),
+				entity.FormatType(destination))
 		default:
 			panic(fmt.Sprint (
 				"BUG: analyzer doesnt know about mode", mode))
@@ -152,7 +156,8 @@ func (this *Tree) canAssignCoerce (
 	fail := func () error {
 		return errors.Errorf (
 			pos, "cannot convert from %v to %v",
-			source, destination)
+				entity.FormatType(source),
+				entity.FormatType(destination))
 	}
 
 	destination = ReduceToBase(destination)
@@ -222,7 +227,9 @@ func (this *Tree) canAssignSliceArray (
 ) error {
 	err := this.canAssign(pos, destination.Element, strict, source.Element)
 	if err != nil {
-		return errors.Errorf(pos, "expected %v", destination)
+		return errors.Errorf (
+			pos, "expected %v",
+			entity.FormatType(destination))
 	} else {
 		return nil
 	}

analyzer/expression.go

@@ -378,7 +378,9 @@ func (this *Tree) analyzeOperation (
 	error,
 ) {
 	wrongInto := func () (entity.Expression, error) {
-		return nil, errors.Errorf(operation.Position, "expected %v", into)
+		return nil, errors.Errorf (
+			operation.Position, "expected %v",
+			entity.FormatType(into))
 	}
 
 	wrongArgCount := func () (entity.Expression, error) {
@@ -578,18 +580,21 @@ func (this *Tree) analyzeMemberAccess (
 		referenced, ok := ReduceToBase(sourceTypeAny.Referenced).(*entity.TypeStruct)
 		if !ok {
 			return nil, errors.Errorf (
-				access.Position, "cannot access members of %v", source)
+				access.Position, "cannot access members of %v",
+				source)
 		}
 		sourceType = referenced
 	default:
 		return nil, errors.Errorf (
-			access.Position, "cannot access members of %v", source)
+			access.Position, "cannot access members of %v",
+			source)
 	}
 
 	member, ok := sourceType.MemberMap[access.Member]
 	if !ok {
 		return nil, errors.Errorf (
-			access.Position, "no member %v", access)
+			access.Position, "no member %v",
+			access)
 	}
 	
 	err = this.canAssign(access.Position, into, mode, member.Type())
@@ -665,7 +670,9 @@ func (this *Tree) analyzeBreak (
 	error,
 ) {
 	if into != nil {
-		return nil, errors.Errorf(brk.Position, "expected %v", into)
+		return nil, errors.Errorf (
+			brk.Position, "expected %v",
+			entity.FormatType(into))
 	}
 
 	loop, ok := this.topLoop()
@@ -700,7 +707,9 @@ func (this *Tree) analyzeReturn (
 	error,
 ) {
 	if into != nil {
-		return nil, errors.Errorf(ret.Position, "expected %v", into)
+		return nil, errors.Errorf (
+			ret.Position, "expected %v",
+			entity.FormatType(into))
 	}
 
 	ret.Declaration, _ = this.topDeclaration()

analyzer/literal.go

@@ -15,13 +15,13 @@ func (this *Tree) analyzeLiteralInt (
 	if !isNumeric(into) {
 		return nil, errors.Errorf (
 			literal.Position, "cannot use integer literal as %v",
-			into)
+			entity.FormatType(into))
 	}
 
 	if isInteger(into) && !inRange(into, int64(literal.Value)) {
 		return nil, errors.Errorf (
 			literal.Position, "integer literal out of range for type %v",
-			into)
+			entity.FormatType(into))
 	}
 
 	literal.Ty = into
@@ -39,7 +39,7 @@ func (this *Tree) analyzeLiteralFloat (
 	if !isFloat(into) {
 		return nil, errors.Errorf (
 			literal.Position, "cannot use float literal as %v",
-			into)
+			entity.FormatType(into))
 	}
 
 	literal.Ty = into
@@ -59,7 +59,7 @@ func (this *Tree) analyzeLiteralString (
 	errCantUse := func () error {
 		return errors.Errorf (
 			literal.Position, "cannot use string literal as %v",
-			into)
+			entity.FormatType(into))
 	}
 
 	fillUTF32 := func () {
@@ -86,13 +86,13 @@ func (this *Tree) analyzeLiteralString (
 				literal.Position,
 				"cannot fit string literal of length " +
 				"%v into %v",
-				length, into)
+				length, entity.FormatType(into))
 		} else if length < 1 {
 			return nil, errors.Errorf (
 				literal.Position,
 				"string literal must have data when " +
 				"assigning to %v",
-				into)
+				entity.FormatType(into))
 		}
 	case *entity.TypeArray:
 		element := ReduceToBase(base.Element)
@@ -176,7 +176,7 @@ func (this *Tree) analyzeLiteralArray (
 	default:
 		return nil, errors.Errorf (
 			literal.Position, "cannot use array literal as %v",
-			into)
+			entity.FormatType(into))
 	}
 
 	for index, element := range literal.Elements {
@@ -201,7 +201,7 @@ func (this *Tree) analyzeLiteralStruct (
 	if !ok {
 		return nil, errors.Errorf (
 			literal.Position, "cannot use struct literal as %v",
-			into)
+			entity.FormatType(into))
 	}
 
 	literal, err := this.assembleStructLiteralMap(literal)
@@ -235,7 +235,7 @@ func (this *Tree) analyzeLiteralBoolean (
 	if !isBoolean(into) {
 		return nil, errors.Errorf (
 			literal.Position, "cannot use boolean literal as %v",
-			into)
+			entity.FormatType(into))
 	}
 
 	literal.Ty = into

analyzer/type_test.go

@@ -162,3 +162,19 @@ testString (test,
 Bird: (~ [fly] [land])
 `)
 }
+
+func TestTypeIntegerLiteralVoid (test *testing.T) {
+testStringErr (test,
+"cannot use integer literal as Void", 2, 10,
+`
+[main] = 5
+`)
+}
+
+func TestTypeStringLiteralVoid (test *testing.T) {
+testStringErr (test,
+"cannot use string literal as Void", 2, 10,
+`
+[main] = 'hello'
+`)
+}

entity/type.go

@@ -208,3 +208,13 @@ func TypesEqual (left, right Type) bool {
 	if  left == nil                    { return true  }
 	return left.Equals(right)
 }
+
+// FormatType returns a string representing a type. If the type is nil, it
+// returns "Void".
+func FormatType (ty Type) string {
+	if ty == nil {
+		return "Void"
+	} else {
+		return ty.String()
+	}
+}