go-delve/delve · error

could not find symbol value for %s

Error message

could not find symbol value for %s

What it means

In compileTypeCastOrFuncCall, when the callee is a plain identifier that is neither a known function nor a resolvable type, Delve checks if it resolves as a type (FindTypeExpr); if not, it produces 'could not find symbol value for <name>' as the fallback error for a failed type cast. This means the identifier could not be resolved to any symbol, function, or type visible at the current location.

Source

Thrown at pkg/proc/evalop/evalcompile.go:539

	}

	switch n := fnnode.(type) {
	case *ast.BasicLit:
		// It can only be a ("type string")(x) type cast
		return ctx.compileTypeCast(node, nil)
	case *ast.ArrayType, *ast.StructType, *ast.FuncType, *ast.InterfaceType, *ast.MapType, *ast.ChanType:
		return ctx.compileTypeCast(node, nil)
	case *ast.SelectorExpr:
		if _, isident := n.X.(*ast.Ident); isident {
			if typ, _ := ctx.FindTypeExpr(n); typ != nil {
				return ctx.compileTypeCast(node, nil)
			}
			return ambiguous()
		}
		return ctx.compileFunctionCall(node, toplevel)
	case *ast.Ident:
		if typ, _ := ctx.FindTypeExpr(n); typ != nil {
			return ctx.compileTypeCast(node, fmt.Errorf("could not find symbol value for %s", n.Name))
		}
		return ctx.compileFunctionCall(node, toplevel)
	case *ast.IndexExpr:
		// Ambiguous, could be a parametric type
		switch n.X.(type) {
		case *ast.Ident, *ast.SelectorExpr:
			// Do the type-cast first since evaluating node.Fun could be expensive.
			err := ctx.compileTypeCast(node, nil)
			if err == nil || err != reader.ErrTypeNotFound {
				return err
			}
			return ctx.compileFunctionCall(node, toplevel)
		default:
			return ctx.compileFunctionCall(node, toplevel)
		}
	case *ast.IndexListExpr:
		return ctx.compileTypeCast(node, nil)
	default:

View on GitHub (pinned to a23773e6c3)

Solutions

1. Check spelling and scope: switch to the frame where the symbol is in scope ('frame N') or qualify with a package name ('main.myFunc')
2. Verify the binary was built with optimizations that didn't eliminate the symbol (use -gcflags='all=-N -l')
3. If it is a type cast, ensure the type name is fully qualified and present in DWARF (not a stripped binary)
4. Use 'locals'/'vars'/'funcs <name>' to confirm the symbol exists before calling it

Example fix

// before
(dlv) call procsess(x) // typo
// after
(dlv) funcs procsess   // verify name
(dlv) call process(x)

// At the REPL: confirm the symbol exists before calling
// (dlv) funcs myFunc
// (dlv) locals
// In tooling: check the identifier against known function/variable lists first.

null

// Wrap evaluation and surface a scope-check hint
res, err := eval(expr)
if err != nil && strings.Contains(err.Error(), "could not find symbol value for") {
	return fmt.Errorf("%w: run 'funcs'/'locals' to verify the symbol is in scope", err)
}

When it happens

Trigger: Calling or casting an unknown identifier, e.g. 'call foo()' where foo is not in scope, or a type conversion like 'T(x)' where T is not a visible type/symbol. Also occurs when the identifier is shadowed, stripped by the compiler (inlined away), or belongs to a package not imported into the current frame.

Common situations: Typo in a function/variable/type name at the (dlv) prompt; referring to a symbol optimized out or inlined; using a type from a package whose DWARF info isn't loaded (stripped binaries); generics/parametric types partially matching.

Related errors

• shift count must not be negative
• invalid argument %s (type %s) for cap
• wrong number of arguments to len: %d
• invalid argument %s (type %s) for len
• wrong number of arguments to complex: %d

AI-assisted analysis of go-delve/delve@a23773e6c3 (2026-08-31). Data as JSON: /api/errors/091d36e18306a117. Report an issue: GitHub.