More info when Do func has wrong signature

Catch panic and show a terser call stack and the file and line number of
the function that has the wrong arguments

Before:

```
...
    Test Panicked
    reflect: Call using *[]*models.ImageDefinition as type int
    /usr/local/Cellar/go/1.10/libexec/src/runtime/panic.go:505

    Full Stack Trace
    	/usr/local/Cellar/go/1.10/libexec/src/runtime/panic.go:505 +0x229
    reflect.Value.call(0x4889200, 0x49e60c0, 0x13, 0x49b4159, 0x4, 0xc4203c1c20, 0x3, 0x3, 0x49af000, 0x485f4c0, ...)
    	/usr/local/Cellar/go/1.10/libexec/src/reflect/value.go:377 +0x1202
    reflect.Value.Call(0x4889200, 0x49e60c0, 0x13, 0xc4203c1c20, 0x3, 0x3, 0x94, 0x0, 0x0)
    	/usr/local/Cellar/go/1.10/libexec/src/reflect/value.go:308 +0xa4
    git.corp.adobe.com/adobe-platform/flight-director/vendor/github.com/golang/mock/gomock.(*Call).Do.func1(0xc4202126c0, 0x3, 0x4, 0xc4201b7e40, 0x2, 0x2)
    	/Users/abramowi/go/src/git.corp.adobe.com/adobe-platform/flight-director/vendor/github.com/golang/mock/gomock/call.go:154 +0x23f
    git.corp.adobe.com/adobe-platform/flight-director/vendor/github.com/golang/mock/gomock.(*Controller).Call(0xc420177230, 0x4913f80, 0xc42007f7a0, 0x49b5a9c, 0x6, 0xc4202126c0, 0x3, 0x4, 0x0, 0x0, ...)
    	/Users/abramowi/go/src/git.corp.adobe.com/adobe-platform/flight-director/vendor/github.com/golang/mock/gomock/controller.go:170 +0x167
    git.corp.adobe.com/adobe-platform/flight-director/mocks/shared/db.(*MockWrapper).Select(0xc42007f7a0, 0x4829a00, 0xc420212620, 0xc4201de180, 0x34, 0xc420478520, 0x1, 0x1, 0x40133b8, 0x120, ...)
    	/Users/abramowi/go/src/git.corp.adobe.com/adobe-platform/flight-director/mocks/shared/db/wrapper.go:82 +0x218
    git.corp.adobe.com/adobe-platform/flight-director/shared/db.(*QueryFilter).SelectIntoEntities(0xc420334988, 0x4a70c00, 0xc42007f7a0, 0x4829a00, 0xc420212620, 0x1, 0x0)
    	/Users/abramowi/go/src/git.corp.adobe.com/adobe-platform/flight-director/shared/db/query_filter.go:74 +0x202
    ...
```

After:

```
...
    reflect: Call using *[]*models.ImageDefinition as type int (incorrect func args at /Users/abramowi/go/src/git.corp.adobe.com/adobe-platform/flight-director/server/routes/deploys/handlers_test.go:71?)

    git.corp.adobe.com/adobe-platform/flight-director/shared/db.(*QueryFilter).SelectIntoEntities
    	/Users/abramowi/go/src/git.corp.adobe.com/adobe-platform/flight-director/shared/db/query_filter.go:74
    ...
```

Author: msabramo

gomock/call.go

@@ -17,6 +17,7 @@ package gomock
 import (
 	"fmt"
 	"reflect"
+	"runtime"
 	"strconv"
 	"strings"
 )
@@ -149,6 +150,27 @@ func (c *Call) Do(f interface{}) *Call {
 				vargs[i] = reflect.Zero(ft.In(i))
 			}
 		}
+		defer func() {
+			if r := recover(); r != nil {
+				errMsg, ok := r.(string)
+
+				// We only handle a very specific panic
+				// If it's not that one, then we "rethrow" the panic
+				// This allows users to use functions that panic in their tests
+				if !ok {
+					panic(r)
+				}
+				if !strings.Contains(errMsg, "reflect: Call using") &&
+					!strings.Contains(errMsg, "reflect.Set: value of") {
+					panic(r)
+				}
+				skipFrames := 8
+				stackTraceStr := "\n\n" + currentStackTrace(skipFrames)
+				funcPC := v.Pointer()
+				file, line := runtime.FuncForPC(funcPC).FileLine(funcPC)
+				c.t.Fatalf("%s (incorrect func args at %s:%d?)%+v", errMsg, file, line, stackTraceStr)
+			}
+		}()
 		v.Call(vargs)
 		return nil
 	})
@@ -239,6 +261,25 @@ func (c *Call) SetArg(n int, value interface{}) *Call {
 		case reflect.Slice:
 			setSlice(args[n], v)
 		default:
+			defer func() {
+				if r := recover(); r != nil {
+					errMsg, ok := r.(string)
+
+					// We only handle a very specific panic
+					// If it's not that one, then we "rethrow" the panic
+					// This allows users to use functions that panic in their tests
+					if !ok {
+						panic(r)
+					}
+					if !strings.Contains(errMsg, "reflect: Call using") &&
+						!strings.Contains(errMsg, "reflect.Set: value of") {
+						panic(r)
+					}
+					skipFrames := 8
+					stackTraceStr := "\n\n" + currentStackTrace(skipFrames)
+					c.t.Fatalf("%s%+v", errMsg, stackTraceStr)
+				}
+			}()
 			reflect.ValueOf(args[n]).Elem().Set(v)
 		}
 		return nil
@@ -382,7 +423,7 @@ func (c *Call) matches(args []interface{}) error {
 
 	// Check that the call is not exhausted.
 	if c.exhausted() {
-		return fmt.Errorf("Expected call at %s has already been called the max number of times.", c.origin)
+		return fmt.Errorf("Expected call at %s has already been called the max number of times (%d).", c.origin, c.maxCalls)
 	}
 
 	return nil

gomock/stack.go

@@ -0,0 +1,43 @@
+package gomock
+
+import (
+	"bytes"
+	"fmt"
+	"strings"
+
+	"github.com/pkg/errors"
+)
+
+const skipFrames = 2
+
+type stackTracer interface {
+	StackTrace() errors.StackTrace
+}
+
+func stackTraceStringFromError(err error, skipFrames int) string {
+	if err, ok := err.(stackTracer); ok {
+		return stackTraceString(err.StackTrace(), skipFrames)
+	}
+	return ""
+}
+
+func currentStackTrace(skipFrames int) string {
+	err := errors.New("fake error just to get stack")
+	if err, ok := err.(stackTracer); ok {
+		return stackTraceString(err.StackTrace(), skipFrames)
+	}
+	return ""
+}
+
+func stackTraceString(stackTrace errors.StackTrace, skipFrames int) string {
+	buffer := bytes.NewBufferString("")
+	for i := skipFrames + 1; i < len(stackTrace); i++ {
+		frame := stackTrace[i]
+		buffer.WriteString(fmt.Sprintf("%+v\n", frame))
+		filename := fmt.Sprintf("%s", frame)
+		if strings.Contains(filename, "_test.go") {
+			break
+		}
+	}
+	return buffer.String()
+}