This PR fixes a crash that occurred when requesting completions immediately after a call expression, such as:

letx=someCall()/**/

Problem

The crash was happening in thegetArgumentInfoForCompletions function when it attempted to dereferenceinfo.argumentIndex without checking if it was nil. The stack trace showed:

panic handling request textDocument/completion runtime error: invalid memory address or nil pointer dereferencegithub.com/microsoft/typescript-go/internal/ls.getArgumentInfoForCompletions(...)github.com/microsoft/typescript-go/internal/ls/completions.go:4574 +0x70

Root Cause

When the cursor is positioned after a call expression but not inside its argument list, thegetArgumentIndex function can returnnil. However,getArgumentInfoForCompletions was only checking ifinfo itself was nil, not ifinfo.argumentIndex was nil, before dereferencing it with*info.argumentIndex.

Solution

Added a nil check forinfo.argumentIndex in the condition before creating theargumentInfoForCompletions struct:

ifinfo==nil||info.isTypeParameterList||info.invocation.callInvocation==nil||info.argumentIndex==nil {returnnil}

Testing

• Created comprehensive test cases covering different call expression completion scenarios
• Verified that existing completion tests continue to pass
• Confirmed the fix prevents the crash while maintaining expected completion behavior (users now get infix operator completions likesatisfies,as, etc.)

Fixes#1416.

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