evalute watch expresisons once variables value is set

fixes #8118

src/vs/workbench/parts/debug/common/debug.ts

@@ -575,6 +575,11 @@ export interface IDebugService {
 	 */
 	removeWatchExpressions(id?: string): void;
 
+	/**
+	 * Evaluates all watch expression.
+	 */
+	evaluateWatchExpressions(): TPromise<void>;
+
 	/**
 	 * Starts debugging. If the configOrName is not passed uses the selected configuration in the debug dropdown.
 	 * Also saves all files, manages if compounds are present in the configuration

src/vs/workbench/parts/debug/electron-browser/debugService.ts

@@ -604,6 +604,10 @@ export class DebugService implements debug.IDebugService {
 		this.model.removeWatchExpressions(id);
 	}
 
+	public evaluateWatchExpressions(): TPromise<void> {
+		return this.model.evaluateWatchExpressions(this.viewModel.focusedProcess, this.viewModel.focusedStackFrame);
+	}
+
 	public startDebugging(root: uri, configOrName?: debug.IConfig | string, noDebug = false, topCompoundName?: string): TPromise<any> {
 
 		// make sure to save all files and that the configuration is up to date

src/vs/workbench/parts/debug/electron-browser/debugViewer.ts

@@ -152,7 +152,10 @@ function renderRenameBox(debugService: debug.IDebugService, contextViewService:
 				if (renamed && element.value !== inputBox.value) {
 					element.setVariable(inputBox.value)
 						// if everything went fine we need to refresh ui elements since the variable update can change watch and variables view
-						.done(() => tree.refresh(element, false), errors.onUnexpectedError);
+						.done(() => {
+							tree.refresh(element, false);
+							debugService.evaluateWatchExpressions();
+						}, errors.onUnexpectedError);
 				}
 			}
 

src/vs/workbench/parts/debug/test/common/mockDebug.ts

@@ -83,6 +83,10 @@ export class MockDebugService implements debug.IDebugService {
 
 	public removeWatchExpressions(id?: string): void { }
 
+	public evaluateWatchExpressions(): TPromise<void> {
+		return TPromise.as(null);
+	}
+
 	public startDebugging(root: uri, configOrName?: debug.IConfig | string, noDebug?: boolean): TPromise<any> {
 		return TPromise.as(null);
 	}