[Compiler] Fix compilation of inherited post condition with before expression

[turbolent]

Description

Post conditions inherited from interfaces may have before expressions. Each checker has one before expression extractor, and each before expression extractor keeps its own state for generating fresh variables for the extracted expressions. The compiler combines the inherited post conditions, leading to potential variable declaration clashes.

Prefix the generated variable declarations with the location of the program to disambiguate and avoid clashes.

---

• Targeted PR against master branch
• Linked to Github issue with discussion and accepted design OR link to spec that describes this work
• Code follows the standards mentioned here
• Updated relevant documentation
• Re-reviewed Files changed in the Github PR explorer
• Added appropriate labels

[github-actions]

Dependency Review

✅ No vulnerabilities or license issues or OpenSSF Scorecard issues found.

Scanned Files

None

[github-actions]

Benchstat comparison

• Base branch: onflow:master
• Base commit: f9bedf3

Results

	old.txt	new.txt
	time/op		delta
pkg:github.com/onflow/cadence/runtime goos:linux goarch:amd64
ContractFunctionInvocation-4	403µs ± 0%	416µs ± 0%	~	(p=1.000 n=1+1)
pkg:github.com/onflow/cadence/interpreter goos:linux goarch:amd64
Emit-4	4.08ms ± 0%	4.21ms ± 0%	~	(p=1.000 n=1+1)
pkg:github.com/onflow/cadence/runtime goos:linux goarch:amd64
ExportType/composite_type-4	274ns ± 0%	268ns ± 0%	~	(p=1.000 n=1+1)
ExportType/simple_type-4	78.1ns ± 0%	77.8ns ± 0%	~	(p=1.000 n=1+1)
pkg:github.com/onflow/cadence/sema goos:linux goarch:amd64
FlowTokenContract-4	582µs ± 0%	589µs ± 0%	~	(p=1.000 n=1+1)
pkg:github.com/onflow/cadence/interpreter goos:linux goarch:amd64
ImperativeFib-4	22.0µs ± 0%	20.6µs ± 0%	~	(p=1.000 n=1+1)
InterpretRecursionFib-4	2.09ms ± 0%	2.09ms ± 0%	~	(p=1.000 n=1+1)
NewInterpreter/new_interpreter-4	910ns ± 0%	854ns ± 0%	~	(p=1.000 n=1+1)
NewInterpreter/new_sub-interpreter-4	334ns ± 0%	320ns ± 0%	~	(p=1.000 n=1+1)
pkg:github.com/onflow/cadence/sema goos:linux goarch:amd64
QualifiedIdentifierCreation/One_level-4	2.50ns ± 0%	1.88ns ± 0%	~	(p=1.000 n=1+1)
QualifiedIdentifierCreation/Three_levels-4	81.7ns ± 0%	79.4ns ± 0%	~	(p=1.000 n=1+1)
pkg:github.com/onflow/cadence/runtime goos:linux goarch:amd64
RuntimeFungibleTokenTransferInterpreter-4	594µs ± 0%	607µs ± 0%	~	(p=1.000 n=1+1)
RuntimeFungibleTokenTransferVM-4	649µs ± 0%	630µs ± 0%	~	(p=1.000 n=1+1)
RuntimeResourceDictionaryValues-4	2.83ms ± 0%	2.76ms ± 0%	~	(p=1.000 n=1+1)
RuntimeResourceTracking-4	11.9ms ± 0%	12.4ms ± 0%	~	(p=1.000 n=1+1)
RuntimeScriptNoop-4	14.8µs ± 0%	14.5µs ± 0%	~	(p=1.000 n=1+1)
RuntimeVMInvokeContractImperativeFib-4	27.4µs ± 0%	30.5µs ± 0%	~	(p=1.000 n=1+1)
pkg:github.com/onflow/cadence/sema goos:linux goarch:amd64
SuperTypeInference/arrays-4	217ns ± 0%	222ns ± 0%	~	(p=1.000 n=1+1)
SuperTypeInference/composites-4	97.3ns ± 0%	96.8ns ± 0%	~	(p=1.000 n=1+1)
SuperTypeInference/integers-4	321ns ± 0%	316ns ± 0%	~	(p=1.000 n=1+1)
pkg:github.com/onflow/cadence/interpreter goos:linux goarch:amd64
ValueIsSubtypeOfSemaType-4	67.5ns ± 0%	59.8ns ± 0%	~	(p=1.000 n=1+1)
	alloc/op		delta
pkg:github.com/onflow/cadence/runtime goos:linux goarch:amd64
ContractFunctionInvocation-4	152kB ± 0%	153kB ± 0%	~	(p=1.000 n=1+1)
pkg:github.com/onflow/cadence/interpreter goos:linux goarch:amd64
Emit-4	1.46MB ± 0%	1.46MB ± 0%	~	(p=1.000 n=1+1)
pkg:github.com/onflow/cadence/runtime goos:linux goarch:amd64
ExportType/composite_type-4	120B ± 0%	120B ± 0%	~	(all equal)
ExportType/simple_type-4	0.00B	0.00B	~	(all equal)
pkg:github.com/onflow/cadence/sema goos:linux goarch:amd64
FlowTokenContract-4	215kB ± 0%	215kB ± 0%	~	(p=1.000 n=1+1)
pkg:github.com/onflow/cadence/interpreter goos:linux goarch:amd64
ImperativeFib-4	8.30kB ± 0%	8.30kB ± 0%	~	(all equal)
InterpretRecursionFib-4	1.19MB ± 0%	1.19MB ± 0%	~	(all equal)
NewInterpreter/new_interpreter-4	976B ± 0%	976B ± 0%	~	(all equal)
NewInterpreter/new_sub-interpreter-4	232B ± 0%	232B ± 0%	~	(all equal)
pkg:github.com/onflow/cadence/sema goos:linux goarch:amd64
QualifiedIdentifierCreation/One_level-4	0.00B	0.00B	~	(all equal)
QualifiedIdentifierCreation/Three_levels-4	64.0B ± 0%	64.0B ± 0%	~	(all equal)
pkg:github.com/onflow/cadence/runtime goos:linux goarch:amd64
RuntimeFungibleTokenTransferInterpreter-4	157kB ± 0%	157kB ± 0%	~	(p=1.000 n=1+1)
RuntimeFungibleTokenTransferVM-4	173kB ± 0%	173kB ± 0%	~	(p=1.000 n=1+1)
RuntimeResourceDictionaryValues-4	1.77MB ± 0%	1.76MB ± 0%	~	(p=1.000 n=1+1)
RuntimeResourceTracking-4	9.26MB ± 0%	9.28MB ± 0%	~	(p=1.000 n=1+1)
RuntimeScriptNoop-4	8.00kB ± 0%	7.99kB ± 0%	~	(p=1.000 n=1+1)
RuntimeVMInvokeContractImperativeFib-4	9.80kB ± 0%	9.80kB ± 0%	~	(all equal)
pkg:github.com/onflow/cadence/sema goos:linux goarch:amd64
SuperTypeInference/arrays-4	72.0B ± 0%	72.0B ± 0%	~	(all equal)
SuperTypeInference/composites-4	0.00B	0.00B	~	(all equal)
SuperTypeInference/integers-4	0.00B	0.00B	~	(all equal)
pkg:github.com/onflow/cadence/interpreter goos:linux goarch:amd64
ValueIsSubtypeOfSemaType-4	32.0B ± 0%	32.0B ± 0%	~	(all equal)
	allocs/op		delta
pkg:github.com/onflow/cadence/runtime goos:linux goarch:amd64
ContractFunctionInvocation-4	2.46k ± 0%	2.46k ± 0%	~	(all equal)
pkg:github.com/onflow/cadence/interpreter goos:linux goarch:amd64
Emit-4	39.0k ± 0%	39.0k ± 0%	~	(all equal)
pkg:github.com/onflow/cadence/runtime goos:linux goarch:amd64
ExportType/composite_type-4	3.00 ± 0%	3.00 ± 0%	~	(all equal)
ExportType/simple_type-4	0.00	0.00	~	(all equal)
pkg:github.com/onflow/cadence/sema goos:linux goarch:amd64
FlowTokenContract-4	3.47k ± 0%	3.47k ± 0%	~	(all equal)
pkg:github.com/onflow/cadence/interpreter goos:linux goarch:amd64
ImperativeFib-4	176 ± 0%	176 ± 0%	~	(all equal)
InterpretRecursionFib-4	17.7k ± 0%	17.7k ± 0%	~	(all equal)
NewInterpreter/new_interpreter-4	15.0 ± 0%	15.0 ± 0%	~	(all equal)
NewInterpreter/new_sub-interpreter-4	4.00 ± 0%	4.00 ± 0%	~	(all equal)
pkg:github.com/onflow/cadence/sema goos:linux goarch:amd64
QualifiedIdentifierCreation/One_level-4	0.00	0.00	~	(all equal)
QualifiedIdentifierCreation/Three_levels-4	2.00 ± 0%	2.00 ± 0%	~	(all equal)
pkg:github.com/onflow/cadence/runtime goos:linux goarch:amd64
RuntimeFungibleTokenTransferInterpreter-4	2.98k ± 0%	2.98k ± 0%	~	(all equal)
RuntimeFungibleTokenTransferVM-4	3.04k ± 0%	3.04k ± 0%	~	(all equal)
RuntimeResourceDictionaryValues-4	36.7k ± 0%	36.7k ± 0%	~	(p=1.000 n=1+1)
RuntimeResourceTracking-4	159k ± 0%	159k ± 0%	~	(p=1.000 n=1+1)
RuntimeScriptNoop-4	113 ± 0%	113 ± 0%	~	(all equal)
RuntimeVMInvokeContractImperativeFib-4	197 ± 0%	197 ± 0%	~	(all equal)
pkg:github.com/onflow/cadence/sema goos:linux goarch:amd64
SuperTypeInference/arrays-4	3.00 ± 0%	3.00 ± 0%	~	(all equal)
SuperTypeInference/composites-4	0.00	0.00	~	(all equal)
SuperTypeInference/integers-4	0.00	0.00	~	(all equal)
pkg:github.com/onflow/cadence/interpreter goos:linux goarch:amd64
ValueIsSubtypeOfSemaType-4	1.00 ± 0%	1.00 ± 0%	~	(all equal)

[RZhang05]

Nice! 👍

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

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