Fix undefined checks

src/vs/workbench/parts/tasks/common/problemMatcher.ts

@@ -347,10 +347,10 @@ abstract class AbstractLineMatcher implements ILineMatcher {
 	}
 
 	private createLocation(startLine: number, startColumn: number | undefined, endLine: number | undefined, endColumn: number | undefined): Location {
-		if (startLine && startColumn && endColumn) {
+		if (startColumn !== undefined && endColumn !== undefined) {
 			return { startLineNumber: startLine, startCharacter: startColumn, endLineNumber: endLine || startLine, endCharacter: endColumn };
 		}
-		if (startLine && startColumn) {
+		if (startColumn !== undefined) {
 			return { startLineNumber: startLine, startCharacter: startColumn, endLineNumber: startLine, endCharacter: startColumn };
 		}
 		return { startLineNumber: startLine, startCharacter: 1, endLineNumber: startLine, endCharacter: Number.MAX_VALUE };