Avoid copying loop vars (Go 1.22+) (#7191)

This isn't needed anymore, so now we don't.
Also enabled the copyloopvar linter in case we
accidentally do this in the future.

Signed-off-by: Anders Eknert <anders@styra.com>

.golangci.yaml

@@ -29,4 +29,5 @@ linters:
     - gosimple
     - prealloc
     - unconvert
+    - copyloopvar
     # - gosec # too many false positives

cmd/bench_test.go

@@ -859,7 +859,6 @@ a[4] {
 
 	for _, mode := range modes {
 		for _, tc := range tests {
-			tc := tc // Reassignment prevents loop var scoping issue. (See: https://go.dev/blog/loopvar-preview)
 			t.Run(fmt.Sprintf("%s, %s", tc.note, mode.name), func(t *testing.T) {
 				t.Parallel()
 
@@ -1023,7 +1022,6 @@ a contains 4 if {
 	for _, bundleType := range bundleTypeCases {
 		for _, mode := range modes {
 			for _, tc := range tests {
-				tc := tc // Reassignment prevents loop var scoping issue. (See: https://go.dev/blog/loopvar-preview)
 				t.Run(fmt.Sprintf("%s, %s, %s", bundleType.note, tc.note, mode.name), func(t *testing.T) {
 					t.Parallel()
 

cmd/eval.go

@@ -499,7 +499,6 @@ func evalOnce(ctx context.Context, ectx *evalContext) pr.Output {
 	result.Errors = pr.NewOutputErrors(resultErr)
 	if ectx.builtInErrorList != nil {
 		for _, err := range *(ectx.builtInErrorList) {
-			err := err
 			result.Errors = append(result.Errors, pr.NewOutputErrors(&err)...)
 		}
 	}

debug/debugger.go

@@ -413,7 +413,6 @@ func (s *session) start() error {
 	defer s.mtx.Unlock()
 
 	for _, t := range s.threads {
-		t := t
 		go func() {
 			s.d.logger.Debug("Thread %d started", t.id)
 			s.d.sendEvent(Event{Type: ThreadEventType, Thread: t.id, Message: "started"})

storage/disk/config_test.go

@@ -225,7 +225,6 @@ func TestBadgerConfigFromOptions(t *testing.T) {
 	}
 
 	for _, tc := range tests {
-		tc := tc // copy for capturing loop variable (not needed in Go 1.22+)
 		t.Run(tc.note, func(t *testing.T) {
 			t.Parallel()
 

storage/disk/disk_test.go

@@ -1144,7 +1144,6 @@ func TestDataPartitioningReadsAndWrites(t *testing.T) {
 	}
 
 	for _, tc := range tests {
-		tc := tc // copy for capturing loop variable (not needed in Go 1.22+)
 		t.Run(tc.note, func(t *testing.T) {
 			t.Parallel()
 
@@ -1301,7 +1300,6 @@ func TestDataPartitioningReadNotFoundErrors(t *testing.T) {
 	}
 
 	for _, tc := range tests {
-		tc := tc // copy for capturing loop variable (not needed in Go 1.22+)
 		t.Run(tc.note, func(t *testing.T) {
 			t.Parallel()
 
@@ -1458,7 +1456,6 @@ func TestDataPartitioningWriteNotFoundErrors(t *testing.T) {
 	}
 
 	for _, tc := range tests {
-		tc := tc // copy for capturing loop variable (not needed in Go 1.22+)
 		t.Run(tc.note, func(t *testing.T) {
 			t.Parallel()
 
@@ -1507,7 +1504,6 @@ func TestDataPartitioningWriteInvalidPatchError(t *testing.T) {
 	t.Parallel()
 
 	for _, pt := range []string{"/*", "/foo"} {
-		pt := pt // copy for capturing loop variable (not needed in Go 1.22+)
 		t.Run(pt, func(t *testing.T) {
 			t.Parallel()
 
@@ -1672,7 +1668,6 @@ func TestLookup(t *testing.T) {
 	}
 
 	for _, tc := range cases {
-		tc := tc // copy for capturing loop variable (not needed in Go 1.22+)
 		t.Run(tc.note, func(t *testing.T) {
 			t.Parallel()
 

storage/disk/partition_test.go

@@ -105,7 +105,6 @@ func TestPartitionTrie(t *testing.T) {
 	}
 
 	for _, tc := range tests {
-		tc := tc // copy for capturing loop variable (not needed in Go 1.22+)
 		t.Run(strings.TrimPrefix(tc.path, "/"), func(t *testing.T) {
 			t.Parallel()
 

storage/disk/paths_test.go

@@ -51,7 +51,6 @@ func TestIsDisjoint(t *testing.T) {
 			overlapped: true,
 		},
 	} {
-		tc := tc // copy for capturing loop variable (not needed in Go 1.22+)
 		t.Run(tc.note, func(t *testing.T) {
 			t.Parallel()
 

topdown/crypto_test.go

@@ -667,7 +667,6 @@ xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
 		},
 	}
 	for name, testData := range tests {
-		testData := testData // copy for capturing loop variable (not needed in Go 1.22+)
 		t.Run(name, func(t *testing.T) {
 			t.Parallel()
 
@@ -829,9 +828,9 @@ func TestExtractX509VerifyOptions(t *testing.T) {
 			},
 		},
 		{ // KeyUsages as an array
-			jsonOption: ast.MustParseTerm(`{"DNSName": "test.com", "CurrentTime": 1708447636000000000, 
-				"MaxConstraintComparisons": 5, 				
-				"KeyUsages" : ["KeyUsageAny", "KeyUsageAny", 1, 2,   
+			jsonOption: ast.MustParseTerm(`{"DNSName": "test.com", "CurrentTime": 1708447636000000000,
+				"MaxConstraintComparisons": 5,
+				"KeyUsages" : ["KeyUsageAny", "KeyUsageAny", 1, 2,
 				"KeyUsageServerAuth","KeyUsageClientAuth"]}`),
 			expectVerifyOpt: x509.VerifyOptions{
 				DNSName:                   "test.com",

topdown/errors_test.go

@@ -106,7 +106,6 @@ func TestErrorWrapping(t *testing.T) {
 	}
 
 	for _, tc := range tests {
-		tc := tc // copy for capturing loop variable (not needed in Go 1.22+)
 		t.Run(tc.note, func(t *testing.T) {
 			t.Parallel()
 

topdown/eval_test.go

@@ -116,7 +116,6 @@ func TestMergeWhenHittingNonObject(t *testing.T) {
 	}
 
 	for _, tc := range cases {
-		tc := tc // copy for capturing loop variable (not needed in Go 1.22+)
 		t.Run(tc.note, func(t *testing.T) {
 			t.Parallel()
 
@@ -172,7 +171,6 @@ func TestRefContainsNonScalar(t *testing.T) {
 	}
 
 	for _, tc := range cases {
-		tc := tc // copy for capturing loop variable (not needed in Go 1.22+)
 		t.Run(tc.note, func(t *testing.T) {
 			t.Parallel()
 
@@ -252,7 +250,6 @@ func TestContainsNestedRefOrCall(t *testing.T) {
 	}
 
 	for _, tc := range tests {
-		tc := tc // copy for capturing loop variable (not needed in Go 1.22+)
 		t.Run(tc.note, func(t *testing.T) {
 			t.Parallel()
 
@@ -586,13 +583,13 @@ func TestTopdownVirtualCache(t *testing.T) {
 		{
 			note: "partial object, ref-head, ref with unification scope",
 			module: `package test
-			
+
 			a[x][y][z] := x + y + z if {
 				some x in [1, 2]
 				some y in [3, 4]
 				some z in [5, 6]
 			}
-			
+
 			p if {
 				x := a[1][_][5]   # miss, cache key: data.test.a[1][<_,5>]
 				some foo
@@ -606,14 +603,14 @@ func TestTopdownVirtualCache(t *testing.T) {
 		{
 			note: "partial object, ref-head, ref with unification scope, component order",
 			module: `package test
-			
+
 			a[x][y][a][b] := i if {
 				some x in [1, 2]
 				some y in [3, 4]
 				some a in ["foo", "bar"]
 				some i, b in ["foo", "bar"]
 			}
-			
+
 			p if {
 				x := a[1][_]["foo"]["bar"] # miss, cache key: data.test.a[1][<_,foo,bar>]
 				y := a[1][_]["bar"]["foo"] # miss, cache key: data.test.a[1][<_,bar,foo>]
@@ -626,13 +623,13 @@ func TestTopdownVirtualCache(t *testing.T) {
 		{
 			note: "partial object, ref-head, ref with unification scope, diverging key scope",
 			module: `package test
-			
+
 			a[x][y][z] := x + y + z if {
 				some x in [1, 2]
 				some y in [3, 4]
 				some z in [5, 6]
 			}
-			
+
 			p if {
 				x := a[1][_][5] # miss, cache key: data.test.a[1][<_,5>]
 				y := a[1][_][6] # miss, cache key: data.test.a[1][<_,6>]
@@ -647,13 +644,13 @@ func TestTopdownVirtualCache(t *testing.T) {
 		{
 			note: "partial object, ref-head, ref with unification scope, trailing vars don't contribute to key scope",
 			module: `package test
-				
+
 				a[x][y][z][x] := x + y + z if {
 					some x in [1, 2]
 					some y in [3, 4]
 					some z in [5, 6]
 				}
-				
+
 				p if {
 					x := a[1][_][5][_] # miss, cache key: data.test.a[1][<_,5>]
 					y := a[1][_][5]    # hit, cache key: data.test.a[1][<_,5>]
@@ -667,11 +664,11 @@ func TestTopdownVirtualCache(t *testing.T) {
 			// Regression test for https://github.com/open-policy-agent/opa/issues/6926
 			note: "partial object, ref-head, leaf set, ref with unification scope",
 			module: `package p
-				
+
 				obj.sub[x][x] contains x if some x in ["one", "two"]
-				
+
 				obj[x][x] contains x if x := "whatever"
-				
+
 				main contains x if {
 					[1 | obj.sub[_].one[_]] # miss, cache key: data.p.obj.sub[<_,one>]
 					x := obj.sub[_][_][_]   # miss, cache key: data.p.obj.sub
@@ -683,7 +680,6 @@ func TestTopdownVirtualCache(t *testing.T) {
 	}
 
 	for _, tc := range tests {
-		tc := tc // copy for capturing loop variable (not needed in Go 1.22+)
 		t.Run(tc.note, func(t *testing.T) {
 			t.Parallel()
 
@@ -988,9 +984,9 @@ func TestPartialRule(t *testing.T) {
 			`,
 			query: `data = x`,
 			exp: `[{"x": {"test": {"p": {"foo": {
-						"0": {"bar": "a"}, 
-						"1": {"bar": "b"}, 
-						"2": {"bar": "c"}, 
+						"0": {"bar": "a"},
+						"1": {"bar": "b"},
+						"2": {"bar": "c"},
 						"bar": {"0": "a", "1": "b", "2": "c"}}}}}}]`,
 		},
 		// Intersections with object values
@@ -1131,8 +1127,8 @@ func TestPartialRule(t *testing.T) {
 		{
 			note: "deep query into partial object (ref head) and object value",
 			module: `package test
-				p.q[r] := x if { 
-					r := "foo" 
+				p.q[r] := x if {
+					r := "foo"
 					x := {"bar": {"baz": 1}}
 				}
 			`,
@@ -1258,7 +1254,7 @@ func TestPartialRule(t *testing.T) {
 		{ // enumeration
 			note: "deep query into partial object and object value, full depth, enumeration on object value",
 			module: `package test
-				p.q[r] := x if { 
+				p.q[r] := x if {
 					r := ["foo", "bar"][_]
 					x := {"s": {"do": 0, "re": 1, "mi": 2}}
 				}
@@ -1269,7 +1265,7 @@ func TestPartialRule(t *testing.T) {
 		{ // enumeration
 			note: "deep query into partial object and object value, full depth, enumeration on rule path and object value",
 			module: `package test
-				p.q[r] := x if { 
+				p.q[r] := x if {
 					r := ["foo", "bar"][_]
 					x := {"s": {"do": 0, "re": 1, "mi": 2}}
 				}
@@ -1292,8 +1288,8 @@ func TestPartialRule(t *testing.T) {
 			note: "deep query into partial object (general ref head) and set value",
 			module: `package test
 				import future.keywords
-				p.q[r] contains t if { 
-					r := ["foo", "bar"][_] 
+				p.q[r] contains t if {
+					r := ["foo", "bar"][_]
 					{"do", "re", "mi"}[t]
 				}
 			`,
@@ -1304,8 +1300,8 @@ func TestPartialRule(t *testing.T) {
 			note: "deep query into partial object (general ref head, static tail) and set value",
 			module: `package test
 				import future.keywords
-				p.q[r].s contains t if { 
-					r := ["foo", "bar"][_] 
+				p.q[r].s contains t if {
+					r := ["foo", "bar"][_]
 					{"do", "re", "mi"}[t]
 				}
 			`,
@@ -1316,8 +1312,8 @@ func TestPartialRule(t *testing.T) {
 			note: "deep query into general ref to set value",
 			module: `package test
 				import future.keywords
-				p.q[r].s contains t if { 
-					r := ["foo", "bar"][_] 
+				p.q[r].s contains t if {
+					r := ["foo", "bar"][_]
 					t := ["do", "re", "mi"][_]
 				}
 			`,
@@ -1327,8 +1323,8 @@ func TestPartialRule(t *testing.T) {
 		{
 			note: "deep query into general ref to object value",
 			module: `package test
-				p.q[r].s[t] := u if { 
-					r := ["foo", "bar"][_] 
+				p.q[r].s[t] := u if {
+					r := ["foo", "bar"][_]
 					t := ["do", "re", "mi"][u]
 				}
 			`,
@@ -1339,8 +1335,8 @@ func TestPartialRule(t *testing.T) {
 			note: "deep query into general ref enumerating set values",
 			module: `package test
 				import future.keywords
-				p.q[r].s contains t if { 
-					r := ["foo", "bar"][_] 
+				p.q[r].s contains t if {
+					r := ["foo", "bar"][_]
 					{"do", "re", "mi"}[t]
 				}
 			`,
@@ -1351,8 +1347,8 @@ func TestPartialRule(t *testing.T) {
 		{
 			note: "deep query into partial object and object value, non-tail var",
 			module: `package test
-				p.q[r].s := x if { 
-					r := "foo" 
+				p.q[r].s := x if {
+					r := "foo"
 					x := {"bar": {"baz": 1}}
 				}
 			`,
@@ -1470,7 +1466,7 @@ func TestPartialRule(t *testing.T) {
 					t := ["d", "e", "f"][u]
 				}`,
 			query: `data.test.p.q[x] = y`,
-			exp: `[{"x": "a", "y": {"s": {"d": 0, "e": 1, "f": 2}}}, 
+			exp: `[{"x": "a", "y": {"s": {"d": 0, "e": 1, "f": 2}}},
 					{"x": "b", "y": {"s": {"d": 0, "e": 1, "f": 2}}},
 					{"x": "c", "y": {"s": {"d": 0, "e": 1, "f": 2}}}]`,
 		},
@@ -1535,7 +1531,6 @@ func TestPartialRule(t *testing.T) {
 	}
 
 	for _, tc := range tests {
-		tc := tc // copy for capturing loop variable (not needed in Go 1.22+)
 		t.Run(tc.note, func(t *testing.T) {
 			t.Parallel()