Write a Go type down over the whole declaration, not its first line

[matt-edmondson]

Fixes #63

What was wrong

CLAUDE.md states the decision: a type parameter on a ClassDeclaration is written down rather than written, because a method on a generic Go type needs the parameters in three places and spelled two ways. The emission only half kept it — the type was declared without parameters, and then a field, a parameter and a result went on spelling them:

// over T : struct, INumber<T>
type Length struct {
	Value T
}

func LengthFromMeter(value T) Length[T] {
	return Create(value)
}

Three things disagree in six lines, and go vet says so: undefined: T, and Length[T] subscripts a type that takes no parameters. Nothing in the text shows either.

What changed

The write-down now reaches the whole declaration rather than its first line, which is the resolution the issue calls the smaller one and the one that matches the stated decision.

• GoGenerator holds the parameters a type was written down over for as long as that type's members are being written. A type spelled for one of those names is spelled any; a mention of the type itself carries no arguments, because a type declared without parameters takes none.
• A type parameter on a function is a real one and reaches none of this — func first[T any](values []T) T is unchanged.
• A type declared inside another is written beside it and is not written over these parameters, so it is emitted before the scope opens.
• The note above the declaration now says what became of the parameters, so the comment and the file under it agree — which was the issue's actual complaint.

The same input now comes out as:

// Holds one of whatever it was given.
// over T : Stringer
// each of those is any below, and Boxed itself takes none
type Boxed struct {
	held any
}

func BoxedHold(value any) Boxed {
	return Boxed{held: value}
}

func (self Boxed) Held() any {
	return self.held
}

Spelling SpellType, SpellTypeName and their callers is now instance work rather than static, since the answer depends on which declaration is being written.

Tests

• GoGeneratedSourceCompilesTests grows the case it was missing, which is the point of the issue's Missing coverage section: a struct with a parameterised field, a static factory answering the type, and a driver in the same package that uses both. This is the only way either error is visible — RustGeneratedSourceCompilesTests has had the equivalent all along, which is why Rust's answer was right and this one was not.
• GoGeneratorTests pins the same shape headlessly, so the answer still holds where no Go toolchain is on the path, plus a companion case asserting a function's own parameters stay generic.

Verified by reverting GoGenerator.cs alone and re-running: both new checks fail (./exemplar.go:101:7: undefined: T, invalid operation: Boxed[T] (Boxed is not a generic type)), and pass with the change. Full suite: 861 passed, 0 failed, with a real Go 1.24 toolchain on the path. Release build of the solution is clean.

CLAUDE.md is updated so the stated decision includes the half that makes it hold.

🤖 Generated with Claude Code

https://claude.ai/code/session_01KGA295odwYgzWvncYaLEu3

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Generated by Claude Code

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
100.0% Coverage on New Code
0.0% Duplication on New Code

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