[WIP] cl: ast.OverloadFuncDecl preload overload func #2469

visualfc · 2025-10-11T11:55:47Z

ast.OverloadFuncDecl preload overload func
remove pkgCtx.overpos

gemini-code-assist · 2025-10-11T11:56:04Z

Summary of Changes

Hello @visualfc, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request introduces fundamental changes to the compiler's preloading mechanism to properly support ast.OverloadFuncDecl. It modifies how functions and methods are registered and represented internally, enabling the compiler to recognize and manage overloaded entities. By creating specialized internal objects and a synthetic dispatcher for overloads, this change lays the groundwork for robust overload resolution within the compilation process.

Highlights

Enhanced Function Preloading: The preloadFuncDecl internal function now accepts an overload boolean parameter, allowing the compiler to differentiate between standard and overloaded function declarations during the initial preloading phase.
Specialized Overload Handling: New conditional logic has been introduced to create distinct internal representations for overloaded functions and methods. Instead of directly calling loadFunc, overloaded entities now trigger the creation of gogen.NewOverloadFunc or gogen.NewOverloadMethod objects.
Synthetic Overload Dispatcher: When an ast.OverloadFuncDecl is encountered, the system now generates a synthetic ast.FuncDecl that acts as an overload dispatcher. This dispatcher function is marked as overloaded and accepts a single any type parameter, facilitating runtime overload resolution.
New Constant for Overload Arguments: A new constant, __xgo_overload_args__, has been added to serve as the parameter name for the synthetic overload dispatcher function, ensuring consistent naming.

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niupilot · 2025-10-11T11:59:22Z

cl/compile.go

-					loadFunc(ctx, recv, fname, d, genFnBody)
+					if overload {
+						pkg := ctx.pkg.Types
+						typ := pkg.Scope().Lookup(tname).Type().(*types.Named)


Security & Quality Issue: Unsafe type lookup/assertion chain. This will panic if Lookup(tname) returns nil or type is not *types.Named.

Suggested change

typ := pkg.Scope().Lookup(tname).Type().(*types.Named)

obj := pkg.Scope().Lookup(tname)

if obj == nil {

ctx.handleErrorf(d.Name.Pos(), d.Name.End(), "type %s not found", tname)

return

}

typ, ok := obj.Type().(*types.Named)

if !ok {

ctx.handleErrorf(d.Name.Pos(), d.Name.End(), "type %s is not a named type", tname)

return

}

gogen.NewOverloadMethod(typ, d.Name.Pos(), pkg, fname)

niupilot · 2025-10-11T11:59:23Z

cl/compile.go

 }

+const (
+	overloadArgs = "__xgo_overload_args__"


Documentation: Add doc comment explaining this constant's purpose as placeholder parameter name for preloading overload signatures.

Suggested change

overloadArgs = "__xgo_overload_args__"

const (

// overloadArgs is the placeholder parameter name used when preloading overload function

// signatures. This allows overload functions to be registered in the package scope

// during the preload phase before actual implementations are processed.

overloadArgs = "__xgo_overload_args__"

)

niupilot · 2025-10-11T11:59:24Z

cl/compile.go

+						List: []*ast.Field{
+							&ast.Field{
+								Names: []*ast.Ident{
+									ast.NewIdent(overloadArgs),
+								},
+								Type: ast.NewIdent("any"),
+							},
+						},


Style: Unnecessary & in Field literal (slice already takes address). Also consider adding a comment explaining this placeholder signature.

Suggested change

List: []*ast.Field{

&ast.Field{

Names: []*ast.Ident{

ast.NewIdent(overloadArgs),

},

Type: ast.NewIdent("any"),

},

},

// Create placeholder function signature for overload preloading

// with single parameter (__xgo_overload_args__: any)

Params: &ast.FieldList{

List: []*ast.Field{

{

Names: []*ast.Ident{ast.NewIdent(overloadArgs)},

Type: ast.NewIdent("any"),

},

},

},

niupilot · 2025-10-11T11:59:25Z

Code Review Summary

Clean implementation of overload function preloading. Three areas need attention:

Critical:

Line 1071: Unsafe type lookup/assertion - add nil checks to prevent panic

Documentation:

Line 1361: Add doc comment for overloadArgs constant
Line 1312-1319: Explain placeholder signature purpose

Style:

Line 1312-1319: Remove unnecessary & in Field literal

No performance or security vulnerabilities found beyond the nil check issue.

gemini-code-assist

Code Review

This pull request introduces functionality to preload overloaded functions by modifying preloadFuncDecl to handle an overload flag. When this flag is true, it registers a special placeholder for the overloaded function/method. The changes appear to correctly implement the intended feature. I have one suggestion to improve code clarity by removing an unnecessary part of a newly created AST node.

gemini-code-assist · 2025-10-11T12:02:26Z

cl/compile.go

+				Type: &ast.FuncType{
+					Params: &ast.FieldList{
+						List: []*ast.Field{
+							&ast.Field{
+								Names: []*ast.Ident{
+									ast.NewIdent(overloadArgs),
+								},
+								Type: ast.NewIdent("any"),
+							},
+						},
+					},
+				},


The Type field of this ast.FuncDecl is constructed with a specific signature, but it appears to be unused. When preloadFuncDecl is called with overload=true, as it is here, the code path that uses the Type field is not executed. This makes the Type definition unnecessary and potentially confusing.

To improve clarity and remove this dead code, you can replace this block with Type: nil.

Type: nil,

cl: ast.OverloadFuncDecl preload overload func

35f3f55

visualfc marked this pull request as draft October 11, 2025 11:56

niupilot bot reviewed Oct 11, 2025

View reviewed changes

gemini-code-assist bot reviewed Oct 11, 2025

View reviewed changes

cl: remove pkgCtx.overpos

73d55f2

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[WIP] cl: ast.OverloadFuncDecl preload overload func #2469

[WIP] cl: ast.OverloadFuncDecl preload overload func #2469

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visualfc commented Oct 11, 2025 •

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-						typ := pkg.Scope().Lookup(tname).Type().(*types.Named)
+					obj := pkg.Scope().Lookup(tname)
+					if obj == nil {
+						ctx.handleErrorf(d.Name.Pos(), d.Name.End(), "type %s not found", tname)
+						return
+					}
+					typ, ok := obj.Type().(*types.Named)
+					if !ok {
+						ctx.handleErrorf(d.Name.Pos(), d.Name.End(), "type %s is not a named type", tname)
+						return
+					}
+					gogen.NewOverloadMethod(typ, d.Name.Pos(), pkg, fname)

-	overloadArgs = "__xgo_overload_args__"
+const (
+	// overloadArgs is the placeholder parameter name used when preloading overload function
+	// signatures. This allows overload functions to be registered in the package scope
+	// during the preload phase before actual implementations are processed.
+	overloadArgs = "__xgo_overload_args__"
+)

[WIP] cl: ast.OverloadFuncDecl preload overload func #2469

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[WIP] cl: ast.OverloadFuncDecl preload overload func #2469

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visualfc commented Oct 11, 2025 •

edited

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