Go: add tests for dataflow relating to type aliasing

go/ql/test/library-tests/semmle/go/aliases/DataflowFields/embedding.go

@@ -0,0 +1,32 @@
+package test
+
+import (
+	"test.com/basename/pkg1"
+	"test.com/basename/pkg2"
+)
+
+// Tests that dataflow behaves as expected when loads and stores from a field traverse embeddings that use different type names.
+
+// pkg2.IntStruct is an alias for pkg1.IntStruct
+// Note referring to symbols in different packages is necessary so that Go will assign the fields the same name as well as the same type--
+// for example, if we defined two aliases here named 'IntStruct1' and 'IntStruct2' and embedded them into two types,
+// the types would be non-identical due to having a field implicitly named IntStruct1 and IntStruct2 respectively,
+// even though syntactically it could be addressed without mentioning the field name.
+
+type EmbedsPkg1IntStruct = struct{ pkg1.IntStruct }
+type EmbedsPkg2IntStruct = struct{ pkg2.IntStruct }
+
+func FEmbedded() {
+
+	x := source()
+	pkg1Struct := EmbedsPkg1IntStruct{pkg1.IntStruct{x}}
+
+	GEmbedded(&pkg1Struct)
+
+}
+
+func GEmbedded(pkg2Struct *EmbedsPkg2IntStruct) {
+
+	sink(pkg2Struct.Field) // $ hasValueFlow="selection of Field"
+
+}

go/ql/test/library-tests/semmle/go/aliases/DataflowFields/go.mod

@@ -0,0 +1,3 @@
+module test.com/basename
+
+go 1.23.1

go/ql/test/library-tests/semmle/go/aliases/DataflowFields/pkg1/struct.go

@@ -0,0 +1,5 @@
+package pkg1
+
+type IntStruct struct {
+	Field int
+}

go/ql/test/library-tests/semmle/go/aliases/DataflowFields/pkg2/struct.go

@@ -0,0 +1,7 @@
+package pkg2
+
+import (
+	"test.com/basename/pkg1"
+)
+
+type IntStruct = pkg1.IntStruct

go/ql/test/library-tests/semmle/go/aliases/DataflowFields/simple.go

@@ -0,0 +1,26 @@
+package test
+
+// Tests that dataflow behaves as expected when field loads and stores, and pointer accesses, go via
+// types which are identical, but which use different aliases.
+
+func source() int    { return 0 }
+func sink(value int) {}
+
+type IntAlias = int
+type IntStruct = struct{ field int }
+type IntAliasStruct = struct{ field IntAlias }
+
+func F() {
+
+	x := source()
+	intStruct := IntStruct{x}
+
+	G(&intStruct)
+
+}
+
+func G(intAliasStruct *IntAliasStruct) {
+
+	sink(intAliasStruct.field) // $ hasValueFlow="selection of field"
+
+}

go/ql/test/library-tests/semmle/go/aliases/DataflowFields/test.ql

@@ -0,0 +1,3 @@
+import go
+import TestUtilities.InlineFlowTest
+import DefaultFlowTest

go/ql/test/library-tests/semmle/go/aliases/InterfaceImpls/flow.ql

@@ -0,0 +1,3 @@
+import go
+import TestUtilities.InlineFlowTest
+import DefaultFlowTest

go/ql/test/library-tests/semmle/go/aliases/InterfaceImpls/test.expected

@@ -1,15 +1,22 @@
 callTargets
-| test.go:48:2:48:24 | call to ImplementMe | test.go:12:1:12:69 | function declaration | ImplementMe |
-| test.go:48:2:48:24 | call to ImplementMe | test.go:17:1:17:64 | function declaration | ImplementMe |
-| test.go:48:2:48:24 | call to ImplementMe | test.go:24:1:24:53 | function declaration | ImplementMe |
-| test.go:48:2:48:24 | call to ImplementMe | test.go:31:1:31:59 | function declaration | ImplementMe |
-| test.go:48:2:48:24 | call to ImplementMe | test.go:38:1:38:71 | function declaration | ImplementMe |
-| test.go:48:2:48:24 | call to ImplementMe | test.go:45:1:45:69 | function declaration | ImplementMe |
+| test.go:20:70:20:83 | call to sink | test.go:15:1:15:45 | function declaration | sink |
+| test.go:25:65:25:78 | call to sink | test.go:15:1:15:45 | function declaration | sink |
+| test.go:32:54:32:67 | call to sink | test.go:15:1:15:45 | function declaration | sink |
+| test.go:39:60:39:73 | call to sink | test.go:15:1:15:45 | function declaration | sink |
+| test.go:46:72:46:85 | call to sink | test.go:15:1:15:45 | function declaration | sink |
+| test.go:53:70:53:83 | call to sink | test.go:15:1:15:45 | function declaration | sink |
+| test.go:56:14:56:21 | call to source | test.go:14:1:14:57 | function declaration | source |
+| test.go:57:2:57:29 | call to ImplementMe | test.go:20:1:20:85 | function declaration | ImplementMe |
+| test.go:57:2:57:29 | call to ImplementMe | test.go:25:1:25:80 | function declaration | ImplementMe |
+| test.go:57:2:57:29 | call to ImplementMe | test.go:32:1:32:69 | function declaration | ImplementMe |
+| test.go:57:2:57:29 | call to ImplementMe | test.go:39:1:39:75 | function declaration | ImplementMe |
+| test.go:57:2:57:29 | call to ImplementMe | test.go:46:1:46:87 | function declaration | ImplementMe |
+| test.go:57:2:57:29 | call to ImplementMe | test.go:53:1:53:85 | function declaration | ImplementMe |
 #select
 | file://:0:0:0:0 | basic interface type | file://:0:0:0:0 | basic interface type |
-| file://:0:0:0:0 | basic interface type | test.go:10:6:10:10 | Impl1 |
-| file://:0:0:0:0 | basic interface type | test.go:15:6:15:10 | Impl2 |
-| file://:0:0:0:0 | basic interface type | test.go:20:6:20:10 | Impl3 |
-| file://:0:0:0:0 | basic interface type | test.go:27:6:27:10 | Impl4 |
-| file://:0:0:0:0 | basic interface type | test.go:34:6:34:10 | Impl5 |
-| file://:0:0:0:0 | basic interface type | test.go:41:6:41:10 | Impl6 |
+| file://:0:0:0:0 | basic interface type | test.go:18:6:18:10 | Impl1 |
+| file://:0:0:0:0 | basic interface type | test.go:23:6:23:10 | Impl2 |
+| file://:0:0:0:0 | basic interface type | test.go:28:6:28:10 | Impl3 |
+| file://:0:0:0:0 | basic interface type | test.go:35:6:35:10 | Impl4 |
+| file://:0:0:0:0 | basic interface type | test.go:42:6:42:10 | Impl5 |
+| file://:0:0:0:0 | basic interface type | test.go:49:6:49:10 | Impl6 |

go/ql/test/library-tests/semmle/go/aliases/InterfaceImpls/test.go

@@ -1,49 +1,58 @@
 package intfs
 
+// Tests that dataflow and interface implementation behave as expected when an interface
+// is implemented using an identical type (in the structural sense defined by the go spec)
+// where the two types differ at surface level, i.e. aliases must be followed to determine
+// that they are identical.
+
 type IntAlias = int
 
 type Target = interface {
 	ImplementMe(callable func(struct{ x IntAlias }))
 }
 
+func source() func(struct{ x IntAlias })   { return nil }
+func sink(fptr func(struct{ x IntAlias })) {}
+
 // Simple direct implementation
 type Impl1 struct{}
 
-func (recv Impl1) ImplementMe(callable func(struct{ x IntAlias })) {}
+func (recv Impl1) ImplementMe(callable func(struct{ x IntAlias })) { sink(callable) } // $ hasValueFlow="callable"
 
 // Implementation via unaliasing
 type Impl2 struct{}
 
-func (recv Impl2) ImplementMe(callable func(struct{ x int })) {}
+func (recv Impl2) ImplementMe(callable func(struct{ x int })) { sink(callable) } // $ hasValueFlow="callable"
 
 // Implementation via top-level aliasing
 type Impl3 struct{}
 
 type Impl3Alias = func(struct{ x IntAlias })
 
-func (recv Impl3) ImplementMe(callable Impl3Alias) {}
+func (recv Impl3) ImplementMe(callable Impl3Alias) { sink(callable) } // $ hasValueFlow="callable"
 
 // Implementation via aliasing the struct
 type Impl4 struct{}
 
 type Impl4Alias = struct{ x IntAlias }
 
-func (recv Impl4) ImplementMe(callable func(Impl4Alias)) {}
+func (recv Impl4) ImplementMe(callable func(Impl4Alias)) { sink(callable) } // $ hasValueFlow="callable"
 
 // Implementation via aliasing the struct member
 type Impl5 struct{}
 
 type Impl5Alias = IntAlias
 
-func (recv Impl5) ImplementMe(callable func(struct{ x Impl5Alias })) {}
+func (recv Impl5) ImplementMe(callable func(struct{ x Impl5Alias })) { sink(callable) } // $ hasValueFlow="callable"
 
 // Implementation via defining the method on an alias
 type Impl6 struct{}
 
 type Impl6Alias = Impl6
 
-func (recv Impl6Alias) ImplementMe(callable func(struct{ x int })) {}
+func (recv Impl6Alias) ImplementMe(callable func(struct{ x int })) { sink(callable) } // $ hasValueFlow="callable"
 
 func Caller(target Target) {
-	target.ImplementMe(nil)
+	callable := source()
+	target.ImplementMe(callable)
 }

go/ql/test/library-tests/semmle/go/aliases/MethodDefs/methods.go

@@ -1,5 +1,7 @@
 package aliases
 
+// Tests how interfaces defining identical types are represented in the database.
+
 type IntAlias = int
 
 type S1 = struct{ x int }

go/ql/test/library-tests/semmle/go/aliases/MethodDefs/test.expected

@@ -1,20 +1,20 @@
 distinctDefinedFs
 | 2 |
 declaredEntities
-| methods.go:3:6:3:13 | IntAlias (1 declaration sites) |
-| methods.go:5:6:5:7 | S1 (1 declaration sites) |
-| methods.go:5:19:5:19 | x (2 declaration sites) |
-| methods.go:6:6:6:7 | S2 (1 declaration sites) |
-| methods.go:6:19:6:19 | x (2 declaration sites) |
-| methods.go:8:6:8:7 | I1 (1 declaration sites) |
-| methods.go:8:22:8:22 | F (2 declaration sites) |
-| methods.go:9:6:9:7 | I2 (1 declaration sites) |
-| methods.go:9:22:9:22 | F (2 declaration sites) |
-| methods.go:10:6:10:7 | I3 (1 declaration sites) |
+| methods.go:5:6:5:13 | IntAlias (1 declaration sites) |
+| methods.go:7:6:7:7 | S1 (1 declaration sites) |
+| methods.go:7:19:7:19 | x (2 declaration sites) |
+| methods.go:8:6:8:7 | S2 (1 declaration sites) |
+| methods.go:8:19:8:19 | x (2 declaration sites) |
+| methods.go:10:6:10:7 | I1 (1 declaration sites) |
 | methods.go:10:22:10:22 | F (2 declaration sites) |
-| methods.go:11:6:11:7 | I4 (1 declaration sites) |
+| methods.go:11:6:11:7 | I2 (1 declaration sites) |
 | methods.go:11:22:11:22 | F (2 declaration sites) |
-| methods.go:13:6:13:10 | Test1 (1 declaration sites) |
-| methods.go:13:12:13:17 | param1 (1 declaration sites) |
-| methods.go:13:23:13:28 | param2 (1 declaration sites) |
-| methods.go:13:34:13:36 | arg (1 declaration sites) |
+| methods.go:12:6:12:7 | I3 (1 declaration sites) |
+| methods.go:12:22:12:22 | F (2 declaration sites) |
+| methods.go:13:6:13:7 | I4 (1 declaration sites) |
+| methods.go:13:22:13:22 | F (2 declaration sites) |
+| methods.go:15:6:15:10 | Test1 (1 declaration sites) |
+| methods.go:15:12:15:17 | param1 (1 declaration sites) |
+| methods.go:15:23:15:28 | param2 (1 declaration sites) |
+| methods.go:15:34:15:36 | arg (1 declaration sites) |

go/ql/test/library-tests/semmle/go/aliases/defsuses/defsuses.go

@@ -1,5 +1,8 @@
 package aliases
 
+// Tests how defs and uses of fields are represented in the database
+// when identical types are used.
+
 type IntAlias = int
 
 type S1 = struct{ x int }

go/ql/test/library-tests/semmle/go/aliases/defsuses/test.expected

@@ -1,33 +1,33 @@
 lowLevelDefs
-| defsuses.go:3:6:3:13 | IntAlias | defsuses.go:3:6:3:13 | IntAlias (1 declaration sites) |
-| defsuses.go:5:6:5:7 | S1 | defsuses.go:5:6:5:7 | S1 (1 declaration sites) |
-| defsuses.go:5:19:5:19 | x | defsuses.go:5:19:5:19 | x (2 declaration sites) |
-| defsuses.go:5:19:5:19 | x | defsuses.go:6:19:6:19 | x (2 declaration sites) |
-| defsuses.go:6:6:6:7 | S2 | defsuses.go:6:6:6:7 | S2 (1 declaration sites) |
-| defsuses.go:6:19:6:19 | x | defsuses.go:5:19:5:19 | x (2 declaration sites) |
-| defsuses.go:6:19:6:19 | x | defsuses.go:6:19:6:19 | x (2 declaration sites) |
-| defsuses.go:8:6:8:10 | Test1 | defsuses.go:8:6:8:10 | Test1 (1 declaration sites) |
-| defsuses.go:9:2:9:4 | obj | defsuses.go:9:2:9:4 | obj (1 declaration sites) |
-| defsuses.go:12:6:12:8 | ptr | defsuses.go:12:6:12:8 | ptr (1 declaration sites) |
+| defsuses.go:6:6:6:13 | IntAlias | defsuses.go:6:6:6:13 | IntAlias (1 declaration sites) |
+| defsuses.go:8:6:8:7 | S1 | defsuses.go:8:6:8:7 | S1 (1 declaration sites) |
+| defsuses.go:8:19:8:19 | x | defsuses.go:8:19:8:19 | x (2 declaration sites) |
+| defsuses.go:8:19:8:19 | x | defsuses.go:9:19:9:19 | x (2 declaration sites) |
+| defsuses.go:9:6:9:7 | S2 | defsuses.go:9:6:9:7 | S2 (1 declaration sites) |
+| defsuses.go:9:19:9:19 | x | defsuses.go:8:19:8:19 | x (2 declaration sites) |
+| defsuses.go:9:19:9:19 | x | defsuses.go:9:19:9:19 | x (2 declaration sites) |
+| defsuses.go:11:6:11:10 | Test1 | defsuses.go:11:6:11:10 | Test1 (1 declaration sites) |
+| defsuses.go:12:2:12:4 | obj | defsuses.go:12:2:12:4 | obj (1 declaration sites) |
+| defsuses.go:15:6:15:8 | ptr | defsuses.go:15:6:15:8 | ptr (1 declaration sites) |
 lowLevelUses
-| defsuses.go:3:17:3:19 | int | file://:0:0:0:0 | int (0 declaration sites) |
-| defsuses.go:5:21:5:23 | int | file://:0:0:0:0 | int (0 declaration sites) |
-| defsuses.go:6:21:6:28 | IntAlias | defsuses.go:3:6:3:13 | IntAlias (1 declaration sites) |
-| defsuses.go:8:14:8:16 | int | file://:0:0:0:0 | int (0 declaration sites) |
-| defsuses.go:9:9:9:10 | S1 | defsuses.go:5:6:5:7 | S1 (1 declaration sites) |
-| defsuses.go:10:2:10:4 | obj | defsuses.go:9:2:9:4 | obj (1 declaration sites) |
-| defsuses.go:10:6:10:6 | x | defsuses.go:5:19:5:19 | x (2 declaration sites) |
-| defsuses.go:10:6:10:6 | x | defsuses.go:6:19:6:19 | x (2 declaration sites) |
-| defsuses.go:12:11:12:12 | S2 | defsuses.go:6:6:6:7 | S2 (1 declaration sites) |
-| defsuses.go:13:2:13:4 | ptr | defsuses.go:12:6:12:8 | ptr (1 declaration sites) |
-| defsuses.go:13:9:13:11 | obj | defsuses.go:9:2:9:4 | obj (1 declaration sites) |
-| defsuses.go:15:9:15:11 | ptr | defsuses.go:12:6:12:8 | ptr (1 declaration sites) |
-| defsuses.go:15:13:15:13 | x | defsuses.go:5:19:5:19 | x (2 declaration sites) |
-| defsuses.go:15:13:15:13 | x | defsuses.go:6:19:6:19 | x (2 declaration sites) |
+| defsuses.go:6:17:6:19 | int | file://:0:0:0:0 | int (0 declaration sites) |
+| defsuses.go:8:21:8:23 | int | file://:0:0:0:0 | int (0 declaration sites) |
+| defsuses.go:9:21:9:28 | IntAlias | defsuses.go:6:6:6:13 | IntAlias (1 declaration sites) |
+| defsuses.go:11:14:11:16 | int | file://:0:0:0:0 | int (0 declaration sites) |
+| defsuses.go:12:9:12:10 | S1 | defsuses.go:8:6:8:7 | S1 (1 declaration sites) |
+| defsuses.go:13:2:13:4 | obj | defsuses.go:12:2:12:4 | obj (1 declaration sites) |
+| defsuses.go:13:6:13:6 | x | defsuses.go:8:19:8:19 | x (2 declaration sites) |
+| defsuses.go:13:6:13:6 | x | defsuses.go:9:19:9:19 | x (2 declaration sites) |
+| defsuses.go:15:11:15:12 | S2 | defsuses.go:9:6:9:7 | S2 (1 declaration sites) |
+| defsuses.go:16:2:16:4 | ptr | defsuses.go:15:6:15:8 | ptr (1 declaration sites) |
+| defsuses.go:16:9:16:11 | obj | defsuses.go:12:2:12:4 | obj (1 declaration sites) |
+| defsuses.go:18:9:18:11 | ptr | defsuses.go:15:6:15:8 | ptr (1 declaration sites) |
+| defsuses.go:18:13:18:13 | x | defsuses.go:8:19:8:19 | x (2 declaration sites) |
+| defsuses.go:18:13:18:13 | x | defsuses.go:9:19:9:19 | x (2 declaration sites) |
 distinctDefinedXs
 | 1 |
 distinctUsedXs
 | 1 |
 fieldUseUsePairs
-| defsuses.go:10:6:10:6 | x | defsuses.go:15:13:15:13 | x |
-| defsuses.go:15:13:15:13 | x | defsuses.go:10:6:10:6 | x |
+| defsuses.go:13:6:13:6 | x | defsuses.go:18:13:18:13 | x |
+| defsuses.go:18:13:18:13 | x | defsuses.go:13:6:13:6 | x |