Improved type system checks

src/core/CompileCall.go

@@ -14,7 +14,7 @@ import (
 // All call registers must hold the correct parameter values before the function invocation.
 // Registers that are in use must be saved if they are modified by the function.
 // After the function call, they must be restored in reverse order.
-func (f *Function) CompileCall(root *expression.Expression) (*Function, error) {
+func (f *Function) CompileCall(root *expression.Expression) ([]types.Type, error) {
 	var (
 		pkg      = f.Package
 		pkgNode  *expression.Expression
@@ -29,25 +29,12 @@ func (f *Function) CompileCall(root *expression.Expression) (*Function, error) {
 
 		switch name {
 		case "len":
-			return &Function{
-				Output: []*Output{
-					{
-						Type: types.Int,
-					},
-				},
-			}, f.CompileLen(root)
+			return _len.OutputTypes, f.CompileLen(root)
 		case "syscall":
 			return nil, f.CompileSyscall(root)
 		case "new":
 			typ, err := f.CompileNew(root)
-
-			return &Function{
-				Output: []*Output{
-					{
-						Type: typ,
-					},
-				},
-			}, err
+			return []types.Type{typ}, err
 		case "delete":
 			return nil, f.CompileDelete(root)
 		case "store":
@@ -112,29 +99,16 @@ func (f *Function) CompileCall(root *expression.Expression) (*Function, error) {
 		}
 
 		if !types.Is(typ, fn.Input[i].Type) {
-			if parameters[i].Token.Kind == token.Number && parameters[i].Token.Text(f.File.Bytes) == "0" {
+			_, expectsPointer := fn.Input[i].Type.(*types.Pointer)
+
+			if expectsPointer && parameters[i].Token.Kind == token.Number && parameters[i].Token.Text(f.File.Bytes) == "0" {
 				continue
 			}
 
-			encountered := ""
-			expected := ""
-
-			if typ != nil {
-				encountered = typ.Name()
-			}
-
-			if fn.Input[i].Type != nil {
-				expected = fn.Input[i].Type.Name()
-			}
-
-			return nil, errors.New(&errors.TypeMismatch{
-				Encountered:   encountered,
-				Expected:      expected,
-				ParameterName: fn.Input[i].Name,
-			}, f.File, parameters[i].Token.Position)
+			return nil, errors.New(&errors.TypeMismatch{Encountered: typ.Name(), Expected: fn.Input[i].Type.Name(), ParameterName: fn.Input[i].Name}, f.File, parameters[i].Token.Position)
 		}
 	}
 
 	f.CallSafe(fn, registers)
-	return fn, nil
+	return fn.OutputTypes, nil
 }

src/core/CompileDefinition.go

@@ -40,7 +40,7 @@ func (f *Function) CompileDefinition(node *ast.Define) error {
 	}
 
 	count := 0
-	called, err := f.CompileCall(right)
+	types, err := f.CompileCall(right)
 
 	if err != nil {
 		return err
@@ -53,8 +53,8 @@ func (f *Function) CompileDefinition(node *ast.Define) error {
 			return err
 		}
 
-		if called != nil {
-			variable.Type = called.Output[count].Type
+		if count < len(types) {
+			variable.Type = types[count]
 		}
 
 		f.RegisterRegister(asm.MOVE, variable.Register, f.CPU.Output[count])

src/core/CompileLen.go

@@ -4,17 +4,25 @@ import (
 	"math"
 
 	"git.akyoto.dev/cli/q/src/asm"
+	"git.akyoto.dev/cli/q/src/errors"
 	"git.akyoto.dev/cli/q/src/expression"
+	"git.akyoto.dev/cli/q/src/types"
 )
 
+var _len = Function{OutputTypes: []types.Type{types.Int}}
+
 // CompileLen returns the length of a slice.
 func (f *Function) CompileLen(root *expression.Expression) error {
-	_, register, isTemporary, err := f.Evaluate(root.Children[1])
+	typ, register, isTemporary, err := f.Evaluate(root.Children[1])
 
 	if err != nil {
 		return err
 	}
 
+	if !types.Is(typ, types.AnyArray) {
+		return errors.New(&errors.TypeMismatch{Encountered: typ.Name(), Expected: types.AnyArray.Name(), ParameterName: "array"}, f.File, root.Children[1].Token.Position)
+	}
+
 	f.SaveRegister(f.CPU.Output[0])
 	f.MemoryRegister(asm.LOAD, asm.Memory{Base: register, Offset: -8, OffsetRegister: math.MaxUint8, Length: 8}, f.CPU.Output[0])
 

src/core/CompileReturn.go

@@ -30,12 +30,7 @@ func (f *Function) CompileReturn(node *ast.Return) error {
 				return nil
 			}
 
-			return errors.New(&errors.TypeMismatch{
-				Encountered:   typ.Name(),
-				Expected:      f.Output[i].Type.Name(),
-				ParameterName: "",
-				IsReturn:      true,
-			}, f.File, node.Values[i].Token.Position)
+			return errors.New(&errors.TypeMismatch{Encountered: typ.Name(), Expected: f.Output[i].Type.Name(), ParameterName: "", IsReturn: true}, f.File, node.Values[i].Token.Position)
 		}
 	}
 

src/core/ExpressionToRegister.go

@@ -24,17 +24,21 @@ func (f *Function) ExpressionToRegister(node *expression.Expression, register cp
 	}
 
 	if ast.IsFunctionCall(node) {
-		fn, err := f.CompileCall(node)
+		types, err := f.CompileCall(node)
+
+		if err != nil {
+			return nil, err
+		}
 
 		if register != f.CPU.Output[0] {
 			f.RegisterRegister(asm.MOVE, register, f.CPU.Output[0])
 		}
 
-		if fn == nil || len(fn.Output) == 0 {
-			return nil, err
+		if len(types) == 0 {
+			return nil, nil
 		}
 
-		return fn.Output[0].Type, err
+		return types[0], err
 	}
 
 	if node.Token.Kind == token.Array {

src/core/Function.go

@@ -11,19 +11,20 @@ import (
 // Function represents the smallest unit of code.
 type Function struct {
 	register.Machine
-	Package    string
-	Name       string
-	UniqueName string
-	File       *fs.File
-	Body       token.List
-	Input      []*Input
-	Output     []*Output
-	Functions  map[string]*Function
-	Structs    map[string]*types.Struct
-	DLLs       dll.List
-	Err        error
-	deferred   []func()
-	count      counter
+	Package     string
+	Name        string
+	UniqueName  string
+	File        *fs.File
+	Body        token.List
+	Input       []*Input
+	Output      []*Output
+	OutputTypes []types.Type
+	Functions   map[string]*Function
+	Structs     map[string]*types.Struct
+	DLLs        dll.List
+	Err         error
+	deferred    []func()
+	count       counter
 }
 
 // counter stores how often a certain statement appeared so we can generate a unique label from it.

src/core/ResolveTypes.go

@@ -40,6 +40,8 @@ func (f *Function) ResolveTypes() error {
 		if param.Type == nil {
 			return errors.New(&errors.UnknownType{Name: typeName}, f.File, param.tokens[1].Position)
 		}
+
+		f.OutputTypes = append(f.OutputTypes, param.Type)
 	}
 
 	return nil

tests/errors/TypeMismatch2.q

@@ -0,0 +1,3 @@
+main() {
+	len(123)
+}

tests/errors_test.go

@@ -47,6 +47,7 @@ var errs = []struct {
 	{"MissingType.q", errors.MissingType},
 	{"ReturnCountMismatch.q", &errors.ReturnCountMismatch{Count: 1, ExpectedCount: 0}},
 	{"TypeMismatch.q", &errors.TypeMismatch{Expected: "*Any", Encountered: "Int64", ParameterName: "p"}},
+	{"TypeMismatch2.q", &errors.TypeMismatch{Expected: "[]Any", Encountered: "Int64", ParameterName: "array"}},
 	{"UnknownFunction.q", &errors.UnknownFunction{Name: "unknown"}},
 	{"UnknownFunction2.q", &errors.UnknownFunction{Name: "f"}},
 	{"UnknownIdentifier.q", &errors.UnknownIdentifier{Name: "x"}},