Close recurring Go analyzer and ESLint rule blind spots by Copilot · Pull Request #65410 · github/gh-aw

Copilot · 2026-10-03T19:08:44Z

Several analyzers missed equivalent Go syntax or lost findings across reassignment and control-flow boundaries. Related ESLint rules also missed client aliases and catch aliases, or misclassified bounded arrays.

Go syntax and aliases: Reuse the shared parenthesis helper, recognize pointer type aliases, and preserve alias state at each comparison.
Go control flow: Track resource cleanup across branches and scanner error checks across block boundaries. Cover selector-based slice bounds, bare fmt.Fprint* calls, spaced nolint directives, and non-cmd main packages.
ESLint: Recognize bounded array spreads, fallback and conditional Octokit clients, and catch-error aliases without overlooking later mutation.
Regression coverage: Add focused fixtures for each reported gap, including cases that must not produce a diagnostic.

For example, the analyzers now distinguish an earlier valid finding from a later reassignment:

n := len(s)
_ = n == 0 // report
n = 1
_ = n == 0 // do not report

Fixes [AW Top 10] 10 Close recurring pkg/linters analyzer blind spots #65381

Co-authored-by: pelikhan <4175913+pelikhan@users.noreply.github.com>

Copilot

Copilot review overview

🟡 Changes recommended

Several new traversal paths still lose findings across assignment evaluation, terminal branches, loops, and alias mutation.

Review effort: Balanced
Findings: 8

Open (8)

Tie ordering guards to the referenced value · New
Preserve zero-iteration paths in loop analysis · New
Model continue and goto control flow before checks · New
Unwrap parenthesized calls in expression statements · New
Do not merge states from terminating branches · New
Exclude terminal branches from state merging · New
Apply assignment aliases after analyzing RHS · New
Preserve aliases while analyzing assignment RHS · New

What changed in this PR

Expands Go and ESLint analyzers to recognize equivalent syntax, aliases, and control-flow patterns.

Changes:

Improves alias, parenthesis, selector, and entry-point detection.
Adds branch-aware resource and buffer analysis.
Adds regression fixtures for reported blind spots.

File	Description
`pkg/linters/unchecked-slice-index/uncheckedsliceindex.go`	Handles selector-based bounds.
`pkg/linters/unchecked-slice-index/testdata/src/uncheckedsliceindex/uncheckedsliceindex.go`	Tests selector bounds.
`pkg/linters/typeassertionnil/typeassertionnil.go`	Recognizes pointer aliases.
`pkg/linters/typeassertionnil/testdata/src/typeassertionnil/typeassertionnil.go`	Tests pointer aliases.
`pkg/linters/trimleftright/testdata/src/trimleftright/trimleftright.go`	Tests parenthesized cutsets.
`pkg/linters/tolowerequalfold/tolowerequalfold.go`	Snapshots alias state.
`pkg/linters/tolowerequalfold/testdata/src/tolowerequalfold/tolowerequalfold.go.golden`	Updates expected rewrites.
`pkg/linters/tolowerequalfold/testdata/src/tolowerequalfold/tolowerequalfold.go`	Tests reassignment and parentheses.
`pkg/linters/rawloginlib/testdata/src/entrypoint/entrypoint.go`	Adds main-package fixture.
`pkg/linters/rawloginlib/rawloginlib.go`	Exempts named main packages.
`pkg/linters/rawloginlib/rawloginlib_test.go`	Runs entry-point fixture.
`pkg/linters/panic-in-library-code/testdata/src/entrypoint/entrypoint.go`	Adds main-package fixture.
`pkg/linters/panic-in-library-code/panic-in-library-code.go`	Exempts named main packages.
`pkg/linters/panic-in-library-code/panic-in-library-code_test.go`	Runs entry-point fixture.
`pkg/linters/osexitinlibrary/testdata/src/entrypoint/entrypoint.go`	Adds main-package fixture.
`pkg/linters/osexitinlibrary/osexitinlibrary.go`	Exempts named main packages.
`pkg/linters/osexitinlibrary/osexitinlibrary_test.go`	Runs entry-point fixture.
`pkg/linters/nilctxpassed/testdata/src/nilctxpassed/nilctxpassed.go`	Tests parenthesized nil.
`pkg/linters/nilctxpassed/nilctxpassed.go`	Unwraps nil expressions.
`pkg/linters/manualmutexunlock/testdata/src/manualmutexunlock/manualmutexunlock.go`	Tests branch cleanup.
`pkg/linters/logfatallibrary/testdata/src/entrypoint/entrypoint.go`	Adds main-package fixture.
`pkg/linters/logfatallibrary/logfatallibrary.go`	Exempts named main packages.
`pkg/linters/logfatallibrary/logfatallibrary_test.go`	Runs entry-point fixture.
`pkg/linters/lenstringzero/testdata/src/lenstringzero/lenstringzero.go.golden`	Updates expected rewrites.
`pkg/linters/lenstringzero/testdata/src/lenstringzero/lenstringzero.go`	Tests alias reassignment.
`pkg/linters/lenstringzero/lenstringzero.go`	Snapshots alias state.
`pkg/linters/internal/resourcetracker/testdata/src/resourcetracker/resourcetracker.go`	Tests branch cleanup states.
`pkg/linters/internal/resourcetracker/resourcetracker.go`	Adds branch-aware resource tracking.
`pkg/linters/internal/nolint/nolint.go`	Accepts spaced directives.
`pkg/linters/internal/nolint/nolint_test.go`	Tests spaced directives.
`pkg/linters/internal/astutil/astutil.go`	Unwraps string literals.
`pkg/linters/internal/astutil/astutil_test.go`	Tests parenthesized literals.
`pkg/linters/httprespbodyclose/testdata/src/httprespbodyclose/httprespbodyclose.go`	Tests branch response cleanup.
`pkg/linters/httprespbodyclose/httprespbodyclose.go`	Tracks response states across branches.
`pkg/linters/fprintferrorunchecked/testdata/src/fprintferrorunchecked/fprintferrorunchecked.go`	Tests bare Fprint calls.
`pkg/linters/fprintferrorunchecked/fprintferrorunchecked.go`	Analyzes expression statements.
`pkg/linters/fileclosenotdeferred/testdata/src/fileclosenotdeferred/fileclosenotdeferred.go`	Tests branch file cleanup.
`pkg/linters/errstringmatch/testdata/src/errstringmatch/errstringmatch.go`	Tests parenthesized strings.
`pkg/linters/contextcancelnotdeferred/testdata/src/contextcancelnotdeferred/contextcancelnotdeferred.go`	Tests branch cancellation.
`pkg/linters/closeerrorunchecked/testdata/src/closeerrorunchecked/closeerrorunchecked.go`	Tests parenthesized Close calls.
`pkg/linters/closeerrorunchecked/closeerrorunchecked.go`	Unwraps Close calls.
`pkg/linters/bufioscannererunchecked/testdata/src/basic/good.go`	Tests cross-block checks.
`pkg/linters/bufioscannererunchecked/testdata/src/basic/bad.go`	Tests unreachable checks.
`pkg/linters/bufioscannererunchecked/bufioscannererunchecked.go`	Propagates following statements.
`pkg/linters/bufferresetbeforereuse/testdata/src/a/a.go`	Tests branch and loop states.
`pkg/linters/bufferresetbeforereuse/bufferresetbeforereuse.go`	Adds control-flow state analysis.
`pkg/linters/blankassigncomma/testdata/src/blankassigncomma/blankassigncomma.go`	Tests hash writer exemption.
`pkg/linters/blankassigncomma/blankassigncomma.go`	Exempts hash WriteString calls.
`eslint-factory/src/rules/no-unsafe-catch-error-property.ts`	Tracks catch aliases.
`eslint-factory/src/rules/no-unsafe-catch-error-property.test.ts`	Tests catch aliases and mutation.
`eslint-factory/src/rules/no-math-minmax-array-spread.ts`	Recognizes bounded arrays.
`eslint-factory/src/rules/no-math-minmax-array-spread.test.ts`	Tests bounded and mutable arrays.
`eslint-factory/src/rules/no-github-request-interpolated-route.ts`	Recognizes fallback clients.
`eslint-factory/src/rules/no-github-request-interpolated-route.test.ts`	Tests fallback client aliases.

+            (varName !== frame.varName && catchParamUnchangedSinceAlias(frame, memberExpr) && (isGuardedByAncestorBranch(sourceCode, memberExpr, frame.varName) || hasPriorEarlyExitInstanceofGuard(sourceCode, memberExpr, frame.varName))) ||
+            isCallOrderingGuarded(sourceCode, memberExpr, frame.safeCalls)


+			if nested, ok := n.(*ast.BlockStmt); ok {
+				analyzeStraightLineBlock(pass, nested, written, read, generatedFiles, noLintIndex)


+		if _, returns := stmt.(*ast.ReturnStmt); returns {
+			return false


+			if filecheck.ShouldSkipFilename(position.Filename, generatedFiles) {
+				return
+			}
+			call, ok := stmt.X.(*ast.CallExpr)


+				for pos, then := range variants {
+					if other, ok := elseStates[key][pos]; ok {
+						then.hasManualClose = then.hasManualClose || other.hasManualClose
+						then.hasDeferClose = then.hasDeferClose && other.hasDeferClose
+						if !then.manualClosePos.IsValid() {


+					if other, ok := elseStates[key][pos]; ok {
+						then.hasManual = then.hasManual || other.hasManual
+						then.hasDefer = then.hasDefer && other.hasDefer
+					}


 			case *ast.AssignStmt:
 				collectLenStringAliasesFromAssignStmt(pass, n, aliases)


 			case *ast.AssignStmt:
 				collectAliasesFromAssignStmt(pass, n, aliases)


github-actions · 2026-10-05T23:09:37Z

🎉 This pull request is included in a new release.

Release: v0.91.0

Initial plan

7032d8d

Copilot AI assigned Copilot and pelikhan Oct 3, 2026

Copilot started work on behalf of pelikhan October 3, 2026 19:21 View session

Copilot AI linked an issue Oct 3, 2026 that may be closed by this pull request

[AW Top 10] 10 Close recurring pkg/linters analyzer blind spots #65381

Closed

1 task

Copilot AI and others added 3 commits October 3, 2026 19:27

Plan analyzer blind-spot fixes

b40ccaa

Co-authored-by: pelikhan <4175913+pelikhan@users.noreply.github.com>

Fix recurring Go analyzer and ESLint blind spots

ee4222b

Co-authored-by: pelikhan <4175913+pelikhan@users.noreply.github.com>

Cover review edge cases in analyzer rules

e5e7b5c

Co-authored-by: pelikhan <4175913+pelikhan@users.noreply.github.com>

Copilot AI changed the title ~~[WIP] Fix recurring pkg/linters analyzer blind spots~~ Close recurring Go analyzer and ESLint rule blind spots Oct 3, 2026

Copilot finished work on behalf of pelikhan October 3, 2026 19:46

Copilot AI requested a review from pelikhan October 3, 2026 19:46

pelikhan marked this pull request as ready for review October 3, 2026 19:57

Copilot AI balanced review requested due to automatic review settings October 3, 2026 19:57

pelikhan merged commit 2912a5b into main Oct 3, 2026
1 check passed

pelikhan deleted the copilot/fix-recurring-analyzer-blind-spots branch October 3, 2026 19:57

Copilot started reviewing on behalf of pelikhan October 3, 2026 19:58 View session

Copilot AI reviewed Oct 3, 2026

View reviewed changes

github-actions Bot mentioned this pull request Oct 4, 2026

[deep-report] Fix: mixed pull_request+slash_command workflows skip cancel-in-progress, causing spurious 0-job "failure" runs under rapid PR pu #65455

Closed

Copilot AI mentioned this pull request Oct 4, 2026

Enable cancellation for mixed command and pull-request workflows #65464

Merged

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Close recurring Go analyzer and ESLint rule blind spots - #65410

Close recurring Go analyzer and ESLint rule blind spots#65410
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Copilot AI commented Oct 3, 2026 •

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		(varName !== frame.varName && catchParamUnchangedSinceAlias(frame, memberExpr) && (isGuardedByAncestorBranch(sourceCode, memberExpr, frame.varName) \|\| hasPriorEarlyExitInstanceofGuard(sourceCode, memberExpr, frame.varName))) \|\|
		isCallOrderingGuarded(sourceCode, memberExpr, frame.safeCalls)

		if nested, ok := n.(*ast.BlockStmt); ok {
		analyzeStraightLineBlock(pass, nested, written, read, generatedFiles, noLintIndex)

		if _, returns := stmt.(*ast.ReturnStmt); returns {
		return false

		case *ast.AssignStmt:
		collectLenStringAliasesFromAssignStmt(pass, n, aliases)

		case *ast.AssignStmt:
		collectAliasesFromAssignStmt(pass, n, aliases)

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Copilot review overview

🟡 Changes recommended

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Copilot AI commented Oct 3, 2026 •

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