Spell NaN and infinite float literals in every target language [patch]

[matt-edmondson]

Fixes #159

What changed

#147 fixed non-finite double literals but not float ones. A NaN or infinite float was still written as its round-trip text. That came out as NaNf or -Infinityf in C#, and as the undefined names NaN or -Infinity in Python, C++, C, Rust and Go. The import check only looked for doubles, so a file whose only non-finite literal was a float never got <math.h>, <limits> or Go's "math".

• LanguageGeneratorBase gains a SpellNonFiniteSingle(float) hook. It defaults to the double spelling, which is already correct for C (NAN and INFINITY are float constants), Python and JavaScript.

• Four generators override it with their single-precision spelling:

  Target	NaN	+∞
  C#	float.NaN	float.PositiveInfinity
  C++	std::numeric_limits<float>::quiet_NaN()	std::numeric_limits<float>::infinity()
  Rust	f32::NAN	f32::INFINITY
  Go	float32(math.NaN())	float32(math.Inf(1))

• ContainsNonFiniteDouble is renamed to ContainsNonFiniteLiteral and now counts float literals too. Its three callers (C, C++ and Go) now add the import for a file whose only non-finite literal is a float.

• The Go const exclusion from Go: constant field/local initialised to NaN or ±Infinity is emitted as const X = math.NaN(), which does not compile #160 already covered floats, so a constant float set to NaN is still written as a var.

Tests (NonFiniteDoubleLiteralTests)

• ANonFiniteFloatIsSpelledInTheTargetLanguage: 21 rows, NaN, +∞ and −∞ for each of the seven generators.
• AFileHoldingANonFiniteFloatImportsItsSpelling: C, C++ and Go each import their header or package exactly once.
• GeneratedCFloats_Compile, GeneratedCppFloats_Compile, GeneratedGoFloats_Compile, GeneratedRustFloats_Compile: each compiles a file of float functions returning NaN, +∞ and −∞, plus an inferred float local holding +∞. The C and C++ builds use -Werror.

With the generator changes reverted, 25 of these fail: every spelling row except JavaScript's, all three import rows, and all four compile tests. With the changes, the full suite passes (1143/1143).

The generated C# is still not compiled in tests, which is tracked in #162, so the C# rows check the spelling only.

🤖 Generated with Claude Code

https://claude.ai/code/session_01CkCrYLchcFZxtGF9DyXZHi

---

Generated by Claude Code

[sonarqubecloud]

Quality Gate passed

Issues
3 New issues
0 Accepted issues

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

See analysis details on SonarQube Cloud