fix: detect if wrapper type receiver has a pointer type and unwrap (#97)

See #91 and 4e3fc0 and 142201

```
go test -timeout 30s -run ^TestCompliance/wrapper_slice_append$ ./compiler
```

Fixes: #96

Signed-off-by: Christian Stewart <christian@aperture.us>

Author: paralin

compiler/expr-call.go

@@ -349,9 +349,47 @@ func (c *GoToTSCompiler) writeWrapperTypeMethodCall(exp *ast.CallExpr, selectorE
 	c.tsw.WriteLiterally(selectorExpr.Sel.Name)
 	c.tsw.WriteLiterally("(")
 
-	// First argument is the receiver
-	if err := c.WriteValueExpr(selectorExpr.X); err != nil {
-		return true, fmt.Errorf("failed to write wrapper type method receiver: %w", err)
+	// Write the receiver (the object the method is called on)
+	// For pointer receiver methods, we need to pass the VarRef instead of the value
+	receiverNeedsVarRef := false
+
+	// Check if the method has a pointer receiver by looking at the method signature
+	if selection := c.pkg.TypesInfo.Selections[selectorExpr]; selection != nil {
+		if methodObj := selection.Obj(); methodObj != nil {
+			if methodFunc, ok := methodObj.(*types.Func); ok {
+				if sig, ok := methodFunc.Type().(*types.Signature); ok && sig != nil {
+					if recv := sig.Recv(); recv != nil {
+						if _, isPointer := recv.Type().(*types.Pointer); isPointer {
+							receiverNeedsVarRef = true
+						}
+					}
+				}
+			}
+		}
+	}
+
+	if receiverNeedsVarRef {
+		// For pointer receivers, we need to pass the VarRef
+		// Convert p.field to p._fields.field
+		if selExpr, ok := selectorExpr.X.(*ast.SelectorExpr); ok {
+			if baseIdent, ok := selExpr.X.(*ast.Ident); ok {
+				c.tsw.WriteLiterally(baseIdent.Name)
+				c.tsw.WriteLiterally("._fields.")
+				c.tsw.WriteLiterally(selExpr.Sel.Name)
+			} else {
+				if err := c.WriteValueExpr(selectorExpr.X); err != nil {
+					return true, fmt.Errorf("failed to write wrapper type method receiver: %w", err)
+				}
+			}
+		} else {
+			if err := c.WriteValueExpr(selectorExpr.X); err != nil {
+				return true, fmt.Errorf("failed to write wrapper type method receiver: %w", err)
+			}
+		}
+	} else {
+		if err := c.WriteValueExpr(selectorExpr.X); err != nil {
+			return true, fmt.Errorf("failed to write wrapper type method receiver: %w", err)
+		}
 	}
 
 	// Add other arguments

compiler/spec.go

@@ -376,8 +376,10 @@ func (c *GoToTSCompiler) WriteNamedTypeWithMethods(a *ast.TypeSpec) error {
 			}
 			recvField := funcDecl.Recv.List[0]
 			recvType := recvField.Type
+			isPointerReceiver := false
 			if starExpr, ok := recvType.(*ast.StarExpr); ok {
 				recvType = starExpr.X
+				isPointerReceiver = true
 			}
 
 			// Check for both simple identifiers (FileMode) and generic types (FileMode[T])
@@ -391,12 +393,7 @@ func (c *GoToTSCompiler) WriteNamedTypeWithMethods(a *ast.TypeSpec) error {
 			}
 
 			if recvTypeName == className {
-				if !isInsideFunction {
-					c.tsw.WriteLiterally("export ")
-				}
-
-				// Generate function signature: export function TypeName_MethodName(receiver: TypeName, ...args): ReturnType
-				c.tsw.WriteLiterally("function ")
+				c.tsw.WriteLiterally("export function ")
 				c.tsw.WriteLiterally(className)
 				c.tsw.WriteLiterally("_")
 				c.tsw.WriteLiterally(funcDecl.Name.Name)
@@ -413,7 +410,15 @@ func (c *GoToTSCompiler) WriteNamedTypeWithMethods(a *ast.TypeSpec) error {
 				}
 				c.tsw.WriteLiterally(receiverParamName)
 				c.tsw.WriteLiterally(": ")
-				c.tsw.WriteLiterally(className)
+
+				// For pointer receivers, use VarRef<T>
+				if isPointerReceiver {
+					c.tsw.WriteLiterally("$.VarRef<")
+					c.tsw.WriteLiterally(className)
+					c.tsw.WriteLiterally(">")
+				} else {
+					c.tsw.WriteLiterally(className)
+				}
 
 				// Add other parameters
 				if funcDecl.Type.Params != nil && len(funcDecl.Type.Params.List) > 0 {

compliance/tests/named_slice_wrapper/index.ts

@@ -1 +1,2 @@
+export { ByName_Len, ByName_Less, ByName_Swap } from "./named_slice_wrapper.gs.js"
 export type { ByName } from "./named_slice_wrapper.gs.js"

compliance/tests/named_type_wrapper/index.ts

@@ -1,2 +1,3 @@
+export { MyFileMode_String } from "./named_type_wrapper.gs.js"
 export { FileStatus } from "./named_type_wrapper.gs.js"
 export type { MyFileMode } from "./named_type_wrapper.gs.js"

compliance/tests/type_declaration_receiver/index.ts

@@ -1 +1,2 @@
+export { CustomString_Length, CustomString_Upper, FileMode_Add, FileMode_IsZero, FileMode_String } from "./type_declaration_receiver.gs.js"
 export type { CustomString, FileMode } from "./type_declaration_receiver.gs.js"

compliance/tests/wrapper_slice_append/actual.log

@@ -5,7 +5,7 @@ import * as $ from "@goscript/builtin/index.js";
 
 export type ErrorList = $.Slice<string>;
 
-export function ErrorList_Add(p: ErrorList, msg: string): void {
+export function ErrorList_Add(p: $.VarRef<ErrorList>, msg: string): void {
 	p!.value = $.append(p!.value, msg)
 }
 

compliance/tests/wrapper_slice_append/errlist/errlist.gs.ts

@@ -54,7 +54,7 @@ export class parser {
 export async function main(): Promise<void> {
 	let p: parser = new parser()
 	// this Add method does not work:
-	errlist.ErrorList_Add(p.errors, "error")
+	errlist.ErrorList_Add(p._fields.errors, "error")
 	console.log(p.errors![0])
 
 	// but it does work for a struct type:

compliance/tests/wrapper_slice_append/skip-test

@@ -1,3 +1,3 @@
-export { TestFileMode, TestMyMode } from "./wrapper_type_args.gs.js"
+export { MyMode_IsExecutable, MyMode_String, TestFileMode, TestMyMode } from "./wrapper_type_args.gs.js"
 export { MyDir } from "./wrapper_type_args.gs.js"
 export type { DirInterface, MyMode } from "./wrapper_type_args.gs.js"