Merge pull request #19484 from owen-mc/go/minor-fix

Go: Remove redundant code in `IR::ExtractTupleElementInstruction.getResultType()` and expand tests

Author: owen-mc

go/ql/lib/semmle/go/controlflow/IR.qll

@@ -718,10 +718,6 @@ module IR {
     predicate extractsElement(Instruction base, int idx) { base = this.getBase() and idx = i }
 
     override Type getResultType() {
-      exists(CallExpr c | this.getBase() = evalExprInstruction(c) |
-        result = c.getTarget().getResultType(i)
-      )
-      or
       exists(Expr e | this.getBase() = evalExprInstruction(e) |
         result = e.getType().(TupleType).getComponentType(pragma[only_bind_into](i))
       )

go/ql/test/library-tests/semmle/go/IR/test.expected

@@ -1,6 +1,10 @@
-| test.go:9:2:9:16 | ... := ...[0] | file://:0:0:0:0 | bool |
-| test.go:9:2:9:16 | ... := ...[1] | file://:0:0:0:0 | bool |
-| test.go:15:2:15:20 | ... := ...[0] | file://:0:0:0:0 | string |
-| test.go:15:2:15:20 | ... := ...[1] | file://:0:0:0:0 | bool |
-| test.go:21:2:21:22 | ... := ...[0] | file://:0:0:0:0 | string |
-| test.go:21:2:21:22 | ... := ...[1] | file://:0:0:0:0 | bool |
+| test.go:9:2:9:16 | ... := ...[0] | test.go:9:13:9:16 | <-... | 0 | file://:0:0:0:0 | bool |
+| test.go:9:2:9:16 | ... := ...[1] | test.go:9:13:9:16 | <-... | 1 | file://:0:0:0:0 | bool |
+| test.go:15:2:15:20 | ... := ...[0] | test.go:15:13:15:20 | index expression | 0 | file://:0:0:0:0 | string |
+| test.go:15:2:15:20 | ... := ...[1] | test.go:15:13:15:20 | index expression | 1 | file://:0:0:0:0 | bool |
+| test.go:21:2:21:22 | ... := ...[0] | test.go:21:13:21:22 | type assertion | 0 | file://:0:0:0:0 | string |
+| test.go:21:2:21:22 | ... := ...[1] | test.go:21:13:21:22 | type assertion | 1 | file://:0:0:0:0 | bool |
+| test.go:29:2:29:7 | call to f[0] | test.go:29:4:29:6 | call to g | 0 | file://:0:0:0:0 | int |
+| test.go:29:2:29:7 | call to f[1] | test.go:29:4:29:6 | call to g | 1 | file://:0:0:0:0 | int |
+| test.go:33:2:33:7 | call to f[0] | test.go:33:4:33:6 | call to v | 0 | file://:0:0:0:0 | int |
+| test.go:33:2:33:7 | call to f[1] | test.go:33:4:33:6 | call to v | 1 | file://:0:0:0:0 | int |

go/ql/test/library-tests/semmle/go/IR/test.go

@@ -21,3 +21,14 @@ func testTypeAssert() {
 	got, ok := i.(string)
 	fmt.Printf("%v %v", got, ok)
 }
+
+func f(x, y int)    {}
+func g() (int, int) { return 0, 0 }
+
+func testNestedFunctionCalls() {
+	f(g())
+
+	// Edge case: when we call a function from a variable, `getTarget()` is not defined
+	v := g
+	f(v())
+}

go/ql/test/library-tests/semmle/go/IR/test.ql

@@ -1,4 +1,5 @@
 import go
 
-from IR::ExtractTupleElementInstruction extract
-select extract, extract.getResultType()
+from IR::ExtractTupleElementInstruction extract, IR::Instruction base, int idx, Type resultType
+where extract.extractsElement(base, idx) and resultType = extract.getResultType()
+select extract, base, idx, resultType